2023 |
Ghose KK, Brown JJ, Frankcombe TJ, Page A, Bayon A, 'Density functional theory modeling of critical properties of perovskite oxides for water splitting applications', WILEY INTERDISCIPLINARY REVIEWS-ENERGY AND ENVIRONMENT, 12 (2023) [C1]
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Nova |
2023 |
Baker S, Pagotto J, Duignan TT, Page AJ, 'High-Throughput Aqueous Electrolyte Structure Prediction Using IonSolvR and Equivariant Graph Neural Network Potentials.', J Phys Chem Lett, 14 9508-9515 (2023) [C1]
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Nova |
2023 |
Li X, Chiong R, Hu Z, Page AJ, 'A graph neural network model with local environment pooling for predicting adsorption energies', Computational and Theoretical Chemistry, 1226 114161-114161 (2023) [C1]
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Nova |
2023 |
Bourke T, Gregory KP, Page AJ, 'Hofmeister effects influence bulk nanostructure in a protic ionic liquid.', J Colloid Interface Sci, 645 420-428 (2023) [C1]
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Nova |
2023 |
Gregory KP, Webber GB, Wanless EJ, Page AJ, 'Decomposing Hofmeister effects on amino acid residues with symmetry adapted perturbation theory', ELECTRONIC STRUCTURE, 5 (2023) [C1]
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Nova |
2023 |
Li X, Shi JQ, Page AJ, 'Discovery of Graphene Growth Alloy Catalysts Using High-Throughput Machine Learning.', Nano Lett, 23 9796-9802 (2023) [C1]
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Nova |
2023 |
Kumar A, Craig VSJ, Robertson H, Page AJ, Webber GB, Wanless EJ, et al., 'Specific Ion Effects at the Vapor-Formamide Interface: A Reverse Hofmeister Series in Ion Concentration Depth Profiles.', Langmuir, 39 12618-12626 (2023) [C1]
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Nova |
2022 |
Yusof ENM, Azam M, Sirat SS, Ravoof TBSA, Page AJ, Veerakumarasivam A, et al., 'Dithiocarbazate Ligand-Based Cu(II), Ni(II), and Zn(II) Complexes: Synthesis, Structural Investigations, Cytotoxicity, DNA Binding, and Molecular Docking Studies', Bioinorganic Chemistry and Applications, 2022 (2022) [C1]
S-4-methylbenzyl-ß-N-(2-methoxybenzylmethylene)dithiocarbazate ligand, 1, prepared from S-(4-methylbenzyl)dithiocarbazate, was used to produce a novel series of transition metal c... [more]
S-4-methylbenzyl-ß-N-(2-methoxybenzylmethylene)dithiocarbazate ligand, 1, prepared from S-(4-methylbenzyl)dithiocarbazate, was used to produce a novel series of transition metal complexes of the type, [M (L)2] [M = Cu(II) (2), Ni(II) (3), and Zn(II) (4), L = 1]. The ligand and its complexes were investigated by elemental analysis, FTIR, 1H and 13C-NMR, MS spectrometry, and molar conductivity. In addition, single X-ray crystallography was also performed for ligand, 1, and complex 3. The Hirshfeld surface analyses were also performed to know about various bonding interactions in the ligand, 1, and complex 3. The investigated compounds were also tested to evaluate their cytotoxic behaviour. However, complex 2 showed promising results against MCF-7 and MDA-MB-213 cancer cell lines. Furthermore, the interaction of CT-DNA with ligand, 1, and complex 2 was also studied using the electronic absorption method, revealing that the compounds have potential DNA-binding ability via hydrogen bonding and hydrophobic and van der Waals interactions. A molecular docking study of complex 2 was also carried out, which revealed that free binding free energy value was -7.39 kcal mol-1.
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Nova |
2022 |
Ding LP, McLean B, Xu Z, Kong X, Hedman D, Qiu L, et al., 'Why Carbon Nanotubes Grow.', Journal of the American Chemical Society, 144 5606-5613 (2022) [C1]
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Nova |
2022 |
Mitchell I, Qiu L, Page A, Lamb LD, Ding F, 'Role of Graphitic Bowls in Temperature Dependent Fullerene Formation.', The journal of physical chemistry. A, 126 8955-8963 (2022) [C1]
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Nova |
2022 |
Gregory KP, Elliott GR, Wanless EJ, Webber GB, Page AJ, 'A quantum chemical molecular dynamics repository of solvated ions.', Scientific data, 9 430 (2022) [C1]
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Nova |
2022 |
Ghose KK, Bayon A, Page AJ, 'First-principles thermochemical properties of hexagonal and cubic phase BaMnO3', MATERIALS TODAY COMMUNICATIONS, 31 (2022) [C1]
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Nova |
2022 |
Kumar A, Craig VSJ, Page AJ, Webber GB, Wanless EJ, Andersson G, 'Ion specificity in the measured concentration depth profile of ions at the Vapor-Glycerol interface', JOURNAL OF COLLOID AND INTERFACE SCIENCE, 626 687-699 (2022) [C1]
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Nova |
2022 |
Gregory KP, Elliott GR, Robertson H, Kumar A, Wanless EJ, Webber GB, et al., 'Understanding specific ion effects and the Hofmeister series', PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 24 12682-12718 (2022) [C1]
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Nova |
2022 |
Hourahine B, Aradi B, Blum V, Bonafe F, Buccheri A, Camacho C, et al., 'DFTB+, a software package for efficient approximate density functional theory based atomistic simulations (vol 152, 124101, 2020)', JOURNAL OF CHEMICAL PHYSICS, 157 (2022)
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2021 |
Mclean B, Kauppinen EI, Page AJ, 'Initial competing chemical pathways during floating catalyst chemical vapor deposition carbon nanotube growth', Journal of Applied Physics, 129 (2021) [C1]
Ferrocene (Fc) is an effective precursor for the direct synthesis of high quality single-walled carbon nanotubes (SWCNTs) via floating catalyst chemical vapor deposition (FCCVD). ... [more]
Ferrocene (Fc) is an effective precursor for the direct synthesis of high quality single-walled carbon nanotubes (SWCNTs) via floating catalyst chemical vapor deposition (FCCVD). However, the formation mechanism of the Fe floating catalyst and the SWNCT growth precursors, such as carbon chains, during Fc decomposition are not well understood. Here, we report first principles nonequilibrium quantum chemical molecular dynamics simulations that investigate the decomposition of Fc during FCCVD. We examine the influence of additional growth precursors including ethylene, methane, CO, and CO2 on the Fc decomposition mechanism and show that the dissociation of these species into C2Hx radicals and C atoms provides the key growth agents for the nucleation of carbon chains from Fc-derived species such as cyclopentadienyl rings. Without an additional growth precursor, Fc decomposes via the spontaneous cleavage of Fe-C and C-H bonds, thereby enabling Fe atoms to cluster and form the floating catalyst. On the basis of these simulations, we detail the two competing chemical pathways present during the initial stages of FCCVD: Fe catalyst nanoparticle growth and carbon chain growth. The latter is accelerated in the presence of the additional growth precursors, with the identity of the precursor determining the nature of the balance between these competing pathways.
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Nova |
2021 |
Yusof ENM, Ravoof TBSA, Page AJ, 'Cytotoxicity of Tin(IV)-based compounds: A review', Polyhedron, 198 (2021) [C1]
The objective of this review is to summarise the achievements of tin-based compounds as potential anticancer agents in the last 10 years. Tin-based compounds attracted growing att... [more]
The objective of this review is to summarise the achievements of tin-based compounds as potential anticancer agents in the last 10 years. Tin-based compounds attracted growing attention in many important scientific areas, especially in drug discovery. The motivation of tin-based as anticancer agents arises from the limitations of platinum-based drugs. The major challenge in drug discovery has become to find out the alternatives with enhanced selectivity and specificity towards target biomacromolecules. In this review, we have focussed our attention on tin-based compounds and cytotoxicity studies of tin-based compounds against cancer cells. This mini review also briefly discusses the possible mechanism of action of the tin-based compounds.
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Nova |
2021 |
Abbott AP, Edler KJ, Page AJ, 'Deep eutectic solvents-The vital link between ionic liquids and ionic solutions', JOURNAL OF CHEMICAL PHYSICS, 155 (2021)
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2021 |
Li X, Chiong R, Hu Z, Page AJ, 'Low-Cost Pt Alloys for Heterogeneous Catalysis Predicted by Density Functional Theory and Active Learning', Journal of Physical Chemistry Letters, 12 7305-7311 (2021) [C1]
Pt is a key high-performing catalyst for important chemical conversions, such as biomass conversion and water splitting. Limited Pt reserves, however, demand that we identify more... [more]
Pt is a key high-performing catalyst for important chemical conversions, such as biomass conversion and water splitting. Limited Pt reserves, however, demand that we identify more sustainable alternative catalyst materials for these processes. Here, we combine state-of-the-art graph neural networks and crystal graph machine learning representations with active learning to discover new, low-cost Pt alloy catalysts for biomass reforming and hydrogen evolution reactions. We identify 12 Pt-based alloys which have comparable catalytic activity to that of the exemplar Pt(111) surface. Notably, Cu3Pt and FeCuPt2 exhibit near identical catalytic performance as that of Pt(111). These results demonstrate the potential of machine learning for predicting new catalytic materials without recourse to expensive DFT geometry optimizations, the current bottleneck impeding high-throughput materials discovery. We also examine the performance of d-band theory in elucidating trends in binary and ternary Pt alloys.
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Nova |
2021 |
Brown JJ, Shao Y, Ke Z, Page AJ, 'Anion ordering and vacancy defects in niobium perovskite oxynitrides', Materials Advances, 2 2398-2407 (2021) [C1]
Niobium perovskite oxynitrides are emerging as promising semiconductor materials for solar energy conversion processes, due to their physical properties and amenability to defect ... [more]
Niobium perovskite oxynitrides are emerging as promising semiconductor materials for solar energy conversion processes, due to their physical properties and amenability to defect engineering. However, defect engineering in mixed-anion semiconductors such as perovskite oxynitrides is generally hindered by the absence of long-range order in the crystal lattice, a phenomenon known as anion-ordering. We demonstrate how anion ordering influences the stability and mobility of point defects in two exemplar perovskite oxynitrides, BaNbO2N and LaNbON2. Accurate first-principles calculations show that fully cis-anion orderings in BaNbO2N are more stable than fully trans-anion orderings, whereas anion orderings with mixed dimensionality may be more prevalent in the lower-symmetry LaNbON2. Anion ordering in LaNbON2 is also influenced by a pronounced A-site coordination sphere effect not observed in BaNbO2N, whereby local La-(O,N)12 coordination environments give rise to alternating LaO and LaN layers in the bulk material. Anion order was predicted to effect the redistribution of electrons upon anion vacancy creation to the cation sublattice. Diffusion barriers for O2- vacancies in trans-ordered BaNbO2N were found to be lower than those for N3- vacancies, suggesting that stabilising trans-ordered phases of BaNbO2N will yield more effective retention of nitrogen content in this material. The reverse is the case for LaNbON2, with N3- vacancy defects exhibiting more facile diffusion than O2- vacancy defects. We believe these insights will aid the emergent understanding of defect engineering in mixed-anion perovskite oxynitride semiconductors, and specifically help facilitate strategies for stabilising their nitrogen content.
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Nova |
2021 |
Waite SL, Karton A, Chan B, Page AJ, 'Thermochemical stabilities of giant fullerenes using density functional tight binding theory and isodesmic-type reactions', Journal of Computational Chemistry, 42 222-230 (2021) [C1]
We present a systematic assessment of the density functional tight binding (DFTB) method for calculating heats of formation of fullerenes with isodesmic-type reaction schemes. We ... [more]
We present a systematic assessment of the density functional tight binding (DFTB) method for calculating heats of formation of fullerenes with isodesmic-type reaction schemes. We show that DFTB3-D/3ob can accurately predict ¿fH values of the 1812 structural isomers of C60, reproduce subtle trends in ¿fH values for 24 isolated pentagon rule (IPR) isomers of C84, and predict ¿fH values of giant fullerenes that are in effectively exact agreement with benchmark DSD-PBEP86/def2-QZVPP calculations. For fullerenes up to C320, DFTB ¿fH values are within 1.0 kJ mol-1 of DSD-PBEP86/def2-QZVPP values per carbon atom, and on a per carbon atom basis DFTB3-D/3ob yields exactly the same numerical trend of (¿fH [per carbon] = 722n-0.72 + 5.2 kJ mol-1). DFTB3-D/3ob is therefore an accurate replacement for high-level DHDFT and composite thermochemical methods in predicting of thermochemical stabilities of giant fullerenes and analogous nanocarbon architectures.
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Nova |
2021 |
Li X, Chiong R, Page AJ, 'Group and Period-Based Representations for Improved Machine Learning Prediction of Heterogeneous Alloy Catalysts.', The Journal of Physical Chemistry Letters, 12 5156-5162 (2021) [C1]
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Nova |
2021 |
Gregory KP, Wanless EJ, Webber GB, Craig VSJ, Page AJ, 'The electrostatic origins of specific ion effects: Quantifying the Hofmeister series for anions', Chemical Science, 12 15007-15015 (2021) [C1]
Life as we know it is dependent upon water, or more specifically salty water. Without dissolved ions, the interactions between biological molecules are insufficiently complex to s... [more]
Life as we know it is dependent upon water, or more specifically salty water. Without dissolved ions, the interactions between biological molecules are insufficiently complex to support life. This complexity is intimately tied to the variation in properties induced by the presence of different ions. These specific ion effects, widely known as Hofmeister effects, have been known for more than 100 years. They are ubiquitous throughout the chemical, biological and physical sciences. The origin of these effects and their relative strengths is still hotly debated. Here we reconsider the origins of specific ion effects through the lens of Coulomb interactions and establish a foundation for anion effects in aqueous and non-aqueous environments. We show that, for anions, the Hofmeister series can be explained and quantified by consideration of site-specific electrostatic interactions. This can simply be approximated by the radial charge density of the anion, which we have calculated for commonly reported ions. This broadly quantifies previously unpredictable specific ion effects, including those known to influence solution properties, virus activities and reaction rates. Furthermore, in non-aqueous solvents, the relative magnitude of the anion series is dependent on the Lewis acidity of the solvent, as measured by the Gutmann Acceptor Number. Analogous SIEs for cations bear limited correlation with their radial charge density, highlighting a fundamental asymmetry in the origins of specific ion effects for anions and cations, due to competing non-Coulombic phenomena. This journal is
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Nova |
2021 |
Brown JJ, Page AJ, 'Reaction pathways in the solid state and the Hubbard U correction', JOURNAL OF CHEMICAL PHYSICS, 154 (2021) [C1]
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Nova |
2020 |
Ghose KK, Bayon A, Page AJ, 'Electronic Structure and High-Temperature Thermochemistry of Oxygen-Deficient BaMO3 (M = Ti - Cu) Perovskites', JOURNAL OF PHYSICAL CHEMISTRY C, 124 27055-27063 (2020) [C1]
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Nova |
2020 |
McLean B, Webber GB, Page AJ, 'Energy and Charge Transfer at the Boron Nitride Nanotube - Catalyst Growth Interface', Journal of Physical Chemistry C, 124 11662-11668 (2020) [C1]
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Nova |
2020 |
Hourahine B, Aradi B, Blum V, Bonafé F, Buccheri A, Camacho C, et al., 'DFTB+, a software package for efficient approximate density functional theory based atomistic simulations', Journal of Chemical Physics, 152 (2020) [C1]
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Nova |
2020 |
Md Yusof EN, Latif MAM, Tahir MIM, Sakoff JA, Veerakumarasivam A, Page AJ, et al., 'Homoleptic tin(IV) compounds containing tridentate ONS dithiocarbazate Schiff bases: Synthesis, X-ray crystallography, DFT and cytotoxicity studies', Journal of Molecular Structure, 1205 (2020) [C1]
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Nova |
2020 |
Hussain A, Ding E-X, Mclean B, Mustonen K, Ahmad S, Tavakkoli M, et al., 'Scalable growth of single-walled carbon nanotubes with a highly uniform structure.', Nanoscale, 12 12263-12267 (2020) [C1]
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Nova |
2020 |
Brown JJ, Ke Z, Ma T, Page AJ, 'Front Cover: Defect Engineering for Photocatalysis: From Ternary to Perovskite Oxynitrides (ChemNanoMat 5/2020)', ChemNanoMat, 6 696-696 (2020)
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2020 |
Yusof ENM, Page AJ, Sakoff JA, Simone MI, Veerakumarasivam A, Tiekink ERT, Ravoof TBSA, 'Tin(IV) compounds of tridentate thiosemicarbazone Schiff bases: Synthesis, characterization, in-silico analysis and in vitro cytotoxicity', Polyhedron, 189 (2020) [C1]
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Nova |
2020 |
Bayon A, de la Calle A, Ghose KK, Page A, McNaughton R, 'Experimental, computational and thermodynamic studies in perovskites metal oxides for thermochemical fuel production: A review', International Journal of Hydrogen Energy, 45 12653-12679 (2020) [C1]
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Nova |
2020 |
Yusof ENM, Ishak NNM, Latif MAM, Tahir MIM, Sakoff JA, Page AJ, et al., 'Selective cytotoxicity of organotin(IV) compounds with 2,3-dihydroxybenzyldithiocarbazate Schiff bases', Research on Chemical Intermediates, 46 2351-2379 (2020) [C1]
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Nova |
2020 |
Ahmad S, Mustonen K, McLean B, Jiang H, Zhang Q, Hussain A, et al., 'Hybrid Low-Dimensional Carbon Allotropes Formed in Gas Phase', Advanced Functional Materials, 30 (2020) [C1]
Graphene, carbon nanotubes (CNTs) and fullerenes are the basic set of low-dimensional carbon allotropes. The latter two arise from the former by selective removal and addition of ... [more]
Graphene, carbon nanotubes (CNTs) and fullerenes are the basic set of low-dimensional carbon allotropes. The latter two arise from the former by selective removal and addition of carbon atoms. Nevertheless, given their morphological disparities, the production of each is typically devised from entirely different starting points. Here, it is demonstrated that all three allotropes can nucleate from (pseudo-)spherical, nanometer-sized transition metal clusters in a gas-suspension when the chemical conditions are favorable. The experimental results indicate that graphitic carbon embryos nucleate on the catalyst particles and sometimes transform into 2D graphene flakes through chain polymerization of carbon fragments forming in the surround gas atmosphere. It is further shown that hydrogenation reactions play an essential role by stabilizing the emerging flakes by mitigating the pentagon and heptagon defects that lead into evolution of fulleroids. Ab initio molecular dynamics simulations show that the ratio of hydrogen to carbon in the reaction is a key growth parameter. Since structural formation takes place in a gas-suspension, graphene accompanied by fullerenes and single-walled CNTs can be deposited on any surface at ambient temperature with arbitrary layer thicknesses. This provides a direct route for the production and deposition of graphene-based hybrid thin films for various applications.
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2020 |
Brown JJ, Page AJ, 'The Hubbard-U correction and optical properties of d(0) metal oxide photocatalysts', JOURNAL OF CHEMICAL PHYSICS, 153 (2020) [C1]
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Nova |
2020 |
Brown JJ, Ke Z, Ma T, Page AJ, 'Defect Engineering for Photocatalysis: From Ternary to Perovskite Oxynitrides', ChemNanoMat, 6 708-719 (2020) [C1]
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Nova |
2020 |
Meads H, Hunt J, Page A, Withy L, Plowman R, Calder A, 'Stroke survivors' experiences of upper limb recovery: a systematic review of qualitative studies', PHYSICAL THERAPY REVIEWS, 25 316-330 (2020)
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2019 |
Kimura R, Hijikata Y, Eveleens CA, Page AJ, Irle S, 'Chiral-selective etching effects on carbon nanotube growth at edge carbon atoms', JOURNAL OF COMPUTATIONAL CHEMISTRY, 40 375-380 (2019) [C1]
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Nova |
2019 |
Stefanovic R, Chen Z, FitzGerald PA, Warr GG, Atkin R, Page AJ, Webber GB, 'Effect of halides on the solvation of poly(ethylene oxide) in the ionic liquid propylammonium nitrate.', Journal of Colloid and Interface Science, 534 649-654 (2019) [C1]
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Nova |
2019 |
McLean B, Webber GB, Page AJ, 'Boron Nitride Nanotube Nucleation via Network Fusion during Catalytic Chemical Vapor Deposition.', Journal of the American Chemical Society, 141 13385-13393 (2019) [C1]
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Nova |
2019 |
Karton A, Waite SL, Page AJ, 'Performance of DFT for C-60 Isomerization Energies: A Noticeable Exception to Jacob's Ladder', JOURNAL OF PHYSICAL CHEMISTRY A, 123 257-266 (2019) [C1]
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Nova |
2019 |
Bown JJ, Page AJ, 'Vacancy diffusion barriers in TaON and Ta3N5 water-splitting photocatalysts', JOURNAL OF MATERIALS CHEMISTRY A, 7 13029-13035 (2019) [C1]
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Nova |
2019 |
Eveleens CA, Page AJ, 'Catalyst- and Etchant-Dependent Mechanisms of Single-Walled Carbon Nanotube Nucleation during Chemical Vapor Deposition', Journal of Physical Chemistry C, 123 10622-10629 (2019) [C1]
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Nova |
2019 |
McLean B, Webber GB, Page AJ, 'Boron Nitride Nanotube Nucleation during Ni-Catalyzed Boron Oxide Chemical Vapor Deposition', Journal of Physical Chemistry C, 123 27875-27883 (2019) [C1]
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Nova |
2019 |
Eveleens CA, Irle S, Page AJ, 'How does acetonitrile modulate single-walled carbon nanotube diameter during CVD growth?', Carbon, 146 535-541 (2019) [C1]
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Nova |
2019 |
Stefanovic R, Webber GB, Page AJ, 'Polymer solvation in choline chloride deep eutectic solvents modulated by the hydrogen bond donor', Journal of Molecular Liquids, 279 584-593 (2019) [C1]
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Nova |
2019 |
Nadia Md Yusof E, Latif MAM, Tahir MIM, Sakoff J, Simone M, Page AJ, et al., 'o-Vanillin Derived Schiff Bases and Their
Organotin(IV) Compounds: Synthesis, Structural
Characterisation, In-Silico Studies and Cytotoxicity', International Journal of Molecular Sciences, 20 (2019) [C1]
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Nova |
2019 |
Ghose KK, Bayon A, Hinkley J, Page AJ, 'Electronic structure and high-temperature thermochemistry of BaZrO3-d perovskite from first-principles calculations', Physical Chemistry Chemical Physics, 21 12468-12476 (2019) [C1]
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Nova |
2019 |
Gregory KP, Webber GB, Wanless EJ, Page AJ, 'Lewis Strength Determines Specific-Ion Effects in Aqueous and Nonaqueous Solvents.', The Journal of Physical Chemistry. A, 123 6420-6429 (2019) [C1]
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Nova |
2019 |
Li X, Chiong R, Hu Z, Cornforth D, Page MJ, 'Improved Representations of Heterogeneous Carbon Reforming Catalysis Using Machine Learning', JOURNAL OF CHEMICAL THEORY AND COMPUTATION, 15 6882-6894 (2019) [C1]
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Nova |
2019 |
Geng W, Xiao J, Brown JJ, Page AJ, Ke Z, 'New Phosphorene by Phase Combination with Tunable Electronic and Mechanical Properties', JOURNAL OF PHYSICAL CHEMISTRY C, 123 10788-10794 (2019) [C1]
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Nova |
2018 |
Mitchell I, Irle S, Page AJ, 'Inducing regioselective chemical reactivity in graphene with alkali metal intercalation', Physical Chemistry Chemical Physics, 20 19987-19994 (2018) [C1]
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Nova |
2018 |
Nadia Md Yusof E, Tiekink ERT, Jotani MM, Simone M, Page A, Begum T, 'Synthesis, characterisation and structure determination of 3-[(1Z)-{2-[bis({[(2-methylphenyl)methyl]sulfanyl})methylidene]hydrazin-1-ylidene}methyl]benzene-1,2-diol', JOURNAL OF MOLECULAR STRUCTURE, 1171 650-657 (2018) [C1]
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Nova |
2018 |
Stefanovic R, Webber GB, Page AJ, 'Nanostructure of propylammonium nitrate in the presence of poly(ethylene oxide) and halide salts', Journal of Chemical Physics, 148 193826-1-193826-14 (2018) [C1]
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Nova |
2018 |
Mitchell I, Page AJ, 'The influence of hydrogen on transition metal - Catalysed graphene nucleation', CARBON, 128 215-223 (2018) [C1]
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Nova |
2018 |
Waite SL, Li H, Page AJ, 'NO2 Solvation Structure in Choline Chloride Deep Eutectic Solvents-The Role of the Hydrogen Bond Donor', JOURNAL OF PHYSICAL CHEMISTRY B, 122 4336-4344 (2018) [C1]
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Nova |
2018 |
Brown JJ, Ke Z, Geng W, Page AJ, 'Oxygen Vacancy Defect Migration in Titanate Perovskite Surfaces: Effect of the A-Site Cations', JOURNAL OF PHYSICAL CHEMISTRY C, 122 14590-14597 (2018) [C1]
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Nova |
2018 |
Mitchell I, Aradi B, Page AJ, 'Density functional tight binding-based free energy simulations in the DFTB plus program', JOURNAL OF COMPUTATIONAL CHEMISTRY, 39 2452-2458 (2018) [C1]
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Nova |
2018 |
Waite SL, Chan B, Karton A, Page AJ, 'Accurate Thermochemical and Kinetic Stabilities of C84 Isomers.', The Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory, 122 4768-4777 (2018) [C1]
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Nova |
2018 |
McLean B, Webber GB, Page AJ, 'Boron Nitride Nucleation Mechanism during Chemical Vapor Deposition', Journal of Physical Chemistry C, 122 24341-24349 (2018) [C1]
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Nova |
2017 |
Stefanovic R, Ludwig M, Webber GB, Atkin R, Page AJ, 'Nanostructure, hydrogen bonding and rheology in choline chloride deep eutectic solvents as a function of the hydrogen bond donor', PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 19 3297-3306 (2017) [C1]
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Nova |
2017 |
McLean B, Eveleens CA, Mitchell I, Webber GB, Page AJ, 'Catalytic CVD synthesis of boron nitride and carbon nanomaterials - synergies between experiment and theory', PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 19 26466-26494 (2017) [C1]
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Nova |
2017 |
Eveleens CA, Page AJ, 'Effect of ammonia on chemical vapour deposition and carbon nanotube nucleation mechanisms', NANOSCALE, 9 1727-1737 (2017) [C1]
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Nova |
2016 |
Mitchell I, Irle S, Page AJ, 'A global reaction route mapping-based kinetic Monte Carlo algorithm', JOURNAL OF CHEMICAL PHYSICS, 145 (2016) [C1]
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Nova |
2016 |
Hayashi T, Hijikata Y, Page A, Jiang D, Irle S, 'Theoretical analysis of structural diversity of covalent organic framework: Stacking isomer structures thermodynamics and kinetics', Chemical Physics Letters, 664 101-107 (2016)
Covalent organic frameworks (COFs) have attracted much interest due to their utility as functional materials. Unfortunately, experimental synthesis struggles with low single cryst... [more]
Covalent organic frameworks (COFs) have attracted much interest due to their utility as functional materials. Unfortunately, experimental synthesis struggles with low single crystallinity of COFs. We have theoretically investigated isomer structures of a representative two-dimensional COF for both monolayer and three-dimensional stacking orders. We show that rotations of p-phenylene rings are common in monolayers, however, affect the global stacking order substantially. We also discuss the discrepancy between powder X-ray diffraction patterns corresponding to the structures predicted by our calculations and those experimentally observed. The discrepancy demonstrates the importance of dynamics in the self-assembly process of COF organic components.
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2016 |
Saha S, Page AJ, 'The influence of magnetic moment on carbon nanotube nucleation', Carbon, 105 136-143 (2016) [C1]
We demonstrate the impact of magnetic moment on single-walled carbon nanotube (SWCNT) nucleation, using quantum chemical molecular dynamics simulations. The mechanism of SWCNT cap... [more]
We demonstrate the impact of magnetic moment on single-walled carbon nanotube (SWCNT) nucleation, using quantum chemical molecular dynamics simulations. The mechanism of SWCNT cap formation on Fe38 nanoparticle catalysts can be manipulated by altering the total magnetic moment. When the magnetic moment is low, large cap structures dominated by pentagons are formed. Increasing the magnetic moment leads to smaller, "flatter" sp2 carbon networks with a higher proportion of hexagons, which are incapable of lifting away from the catalyst surface. These results demonstrate that SWCNT (n,m) chirality distributions can be potentially manipulated via altering the magnetic moment of the catalyst-carbon interface. We also show that higher magnetic moments leads to slower SWCNT nucleation. This is a consequence of the extent of Fe ¿ C charge transfer, which is proportional to the total magnetic moment. As the magnetic moment is increased, the Fe38 nanoparticle has higher catalytic activity and is able to stabilise carbon in its subsurface region, thereby impeding the nucleation process.
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Nova |
2016 |
Li Y, Hou C, Jiang J, Zhang Z, Zhao C, Page AJ, Ke Z, 'General H-2 Activation Modes for Lewis Acid-Transition Metal Bifunctional Catalysts', ACS CATALYSIS, 6 1655-1662 (2016) [C1]
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Nova |
2016 |
Dar T, Shah K, Moghtaderi B, Page AJ, 'Formation of persistent organic pollutants from 2,4,5-trichlorothiophenol combustion: a density functional theory investigation', Journal of Molecular Modeling, 22 (2016) [C1]
Polychlorinated dibenzothiophene (PCDT) and polychlorinated thianthrene (PCTA) are sulfur analogues of dioxins, such as polychlorinated dibenzo-p-dioxins and polychlorinated diben... [more]
Polychlorinated dibenzothiophene (PCDT) and polychlorinated thianthrene (PCTA) are sulfur analogues of dioxins, such as polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F). In this work, we present a detailed mechanistic and kinetic analysis of PCDT and PCTA formation from the combustion of 2,4,5-trichlorothiophenol. It is shown that the formation of these persistent organic pollutants is more favourable, both kinetically and thermodynamically, than their analogous dioxin counterparts. This is rationalised in terms of the different influences of the S¿H and O¿H moieties in the 2,4,5-trichlorothiophenol and 2,4,5-trichlorophenol precursors. Kinetic parameters also indicate that the yield of PCDT should exceed that of PCDD. Finally, we demonstrate here that the degree and pattern of chlorination on the 2,4,5-trichlorothiophenol precursor leads to subtle thermodynamic and kinetic changes to the PCDT/PCTA formation mechanisms. [Figure not available: see fulltext.]
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Nova |
2016 |
Page AJ, Mitchell I, Li HB, Wang Y, Jiao MG, Irle S, Morokuma K, 'Spanning the "parameter Space" of Chemical Vapor Deposition Graphene Growth with Quantum Chemical Simulations', Journal of Physical Chemistry C, 120 13851-13864 (2016) [C1]
Graphene is a 2-dimensional allotrope of carbon with remarkable physicochemical properties. Currently, the most promising route for commercial synthesis of graphene for technologi... [more]
Graphene is a 2-dimensional allotrope of carbon with remarkable physicochemical properties. Currently, the most promising route for commercial synthesis of graphene for technological application is chemical vapor deposition (CVD). The optimization of this chemical process will potentially enable control over crucial properties, such as graphene quality and domain size. Such optimization requires a detailed atomistic understanding of how graphene nucleation and growth take place during CVD. This mechanism depends on a multitude of synthetic parameters: temperature, CVD pressure, catalyst type, facet and phase, feedstock type, and the presence of chemical etchants, to name only a few. In this feature article, we highlight recent quantum chemical simulations of chemical vapor deposition (CVD) graphene nucleation and growth. These simulations aim to systematically span this complex CVD "parameter space" toward providing the necessary understanding of graphene nucleation, to assist the optimization of CVD graphene growth.
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Nova |
2016 |
Chen Z, McLean B, Ludwig M, Stefanovic R, Warr GG, Webber GB, et al., 'Nanostructure of Deep Eutectic Solvents at Graphite Electrode Interfaces as a Function of Potential', Journal of Physical Chemistry C, 120 2225-2233 (2016) [C1]
Atomic force microscopy (AFM), density functional theory (DFT) calculations, and contact angle measurements have been used to investigate the liquid-highly ordered pyrolytic graph... [more]
Atomic force microscopy (AFM), density functional theory (DFT) calculations, and contact angle measurements have been used to investigate the liquid-highly ordered pyrolytic graphite (HOPG) electrode interface for three deep eutectic solvents (DESs) as a function of applied potential. The DESs examined are 1:2 mixtures of choline chloride and urea (ChCl:urea), choline chloride and ethylene glycol (ChCl:ethylene glycol), and choline chloride and glycerol (ChCl:glycerol). DFT calculations reveal that in all cases the molecular component is excluded from the graphite interface at all potentials, while chloride and choline are attracted into the Stern layer at positive and negative potentials, respectively. AFM force curves confirm these trends and also show that the first near surface liquid layer in contact with the Stern layer is rich in the molecular component. The extent of near surface layering increases with potential and the hydrogen bonding capacity of the molecular component. The variation in the macroscopic contact angle with potential is consistent with changes in the Stern layer composition.
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Nova |
2016 |
Eveleens CA, Hijikata Y, Irle S, Page AJ, 'Chiral-Selective Carbon Nanotube Etching with Ammonia: A Quantum Chemical Investigation', Journal of Physical Chemistry C, 120 19862-19870 (2016) [C1]
Density functional theory is employed to demonstrate how ammonia-derived etchant radicals (H, NH, and NH2) can be used to promote particular (n,m) chirality single-walled carbon n... [more]
Density functional theory is employed to demonstrate how ammonia-derived etchant radicals (H, NH, and NH2) can be used to promote particular (n,m) chirality single-walled carbon nanotube (SWCNT) caps during chemical vapor deposition (CVD) growth. We reveal that the chemical reactivity of these etchant radical species with SWCNTs depends on the SWCNT chirality. This reactivity is determined by the extent of disruption to the p-conjugation of the cap structure caused by reaction with the etchant species. H and NH2 attack single carbon atoms and preferentially react with near-zigzag SWCNT caps, whereas NH prefers to attack across C-C bonds and selectively etches near-armchair SWCNT caps. We derive a model for predicting abundances of (n,m) SWCNTs in the presence of ammonia-derived radicals, which is consistent with (n,m) distributions observed in recent CVD experiments with ferrocene and ammonia. This model also demonstrates that chiral-selective etching of SWCNTs during CVD growth can be potentially exploited for achieving chirality control in standard CVD synthesis.
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Nova |
2015 |
Ahubelem N, Shah K, Moghtaderi B, Page AJ, 'Quantum Chemical Molecular Dynamics Simulations of 1,3-Dichloropropene Combustion.', J Phys Chem A, 119 9307-9316 (2015) [C1]
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Nova |
2015 |
Ahubelem N, Shah K, Moghtaderi B, Altarawneh M, Dlugogorski BZ, Page AJ, 'Formation of chlorobenzenes by oxidative thermal decomposition of 1,3-dichloropropene', Combustion and Flame, (2015) [C1]
We combine combustion experiments and density functional theory (DFT) calculations to investigate the formation of chlorobenzenes from oxidative thermal decomposition of 1,3-dichl... [more]
We combine combustion experiments and density functional theory (DFT) calculations to investigate the formation of chlorobenzenes from oxidative thermal decomposition of 1,3-dichloropropene. Mono- to hexa-chlorobenzenes are observed between 800 and 1150. K, and the extent of chlorination was proportional to the combustion temperature. Higher chlorinated congeners of chlorobenzene (tetra-, penta-, hexa-chlorobenzene) are only observed in trace amounts between 950 and 1050. K. DFT calculations indicate that cyclisation of chlorinated hexatrienes proceeds via open-shell radical pathways. These species represent key components in the formation mechanism of chlorinated polyaromatic hydrocarbons. Results presented herein should provide better understanding of the evolution of soot from combustion/pyrolysis of short chlorinated alkenes.
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Nova |
2015 |
Mitchell I, Page AJ, 'Structure and absorption in C60-zinc tetra-phenylporphyrin composite materials: A computational study', Chemical Physics Letters, 620 1-6 (2015) [C1]
© 2014 Elsevier B.V. All rights reserved. We investigate structure and photo-excitation in C60-zinc tetraphenylporphyrin (ZnTPP) and C60F48-ZnTPP complexes, which are promising ca... [more]
© 2014 Elsevier B.V. All rights reserved. We investigate structure and photo-excitation in C60-zinc tetraphenylporphyrin (ZnTPP) and C60F48-ZnTPP complexes, which are promising candidates for organic photovoltaic devices. The C60-ZnTPP complex results from p-p stacking between the fullerene and porphyrin structures, and has a binding energy of 76.0 kJ/mol. Fluorination of the C60 cage leads to decrease in ZnTPP binding, due to reduced p-p stacking interaction. C60-ZnTPP photo-excitation results largely from internal ZnTPP p ¿ p* transitions, although delocalised ZnTPP p ¿ C60 p* transitions are also observed below 300 nm. The more intense photo-excitations of C60F48-ZnTPP arise solely from localised ZnTPP p ¿ p* transitions.
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Nova |
2015 |
Liu B, Liu J, Li HB, Bhola R, Jackson EA, Scott LT, et al., 'Nearly exclusive growth of small diameter semiconducting single-wall carbon nanotubes from organic chemistry synthetic end-cap molecules', Nano Letters, 15 586-595 (2015) [C1]
The inability to synthesize single-wall carbon nanotubes (SWCNTs) possessing uniform electronic properties and chirality represents the major impediment to their widespread applic... [more]
The inability to synthesize single-wall carbon nanotubes (SWCNTs) possessing uniform electronic properties and chirality represents the major impediment to their widespread applications. Recently, there is growing interest to explore and synthesize well-defined carbon nanostructures, including fullerenes, short nanotubes, and sidewalls of nanotubes, aiming for controlled synthesis of SWCNTs. One noticeable advantage of such processes is that no metal catalysts are used, and the produced nanotubes will be free of metal contamination. Many of these methods, however, suffer shortcomings of either low yield or poor controllability of nanotube uniformity. Here, we report a brand new approach to achieve high-efficiency metal-free growth of nearly pure SWCNT semiconductors, as supported by extensive spectroscopic characterization, electrical transport measurements, and density functional theory calculations. Our strategy combines bottom-up organic chemistry synthesis with vapor phase epitaxy elongation. We identify a strong correlation between the electronic properties of SWCNTs and their diameters in nanotube growth. This study not only provides material platforms for electronic applications of semiconducting SWCNTs but also contributes to fundamental understanding of the growth mechanism and controlled synthesis of SWCNTs.
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Nova |
2015 |
Li H, Atkin R, Page AJ, 'Combined Friction Force Microscopy and Quantum Chemical Investigation of the Tribotronic Response at the Propylammonium Nitrate Graphite Interface', Physical Chemistry Chemical Physics, 17 16047-16052 (2015) [C1]
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Nova |
2015 |
Page AJ, Saha S, Li HB, Irle S, Morokuma K, 'Quantum Chemical Simulation of Carbon Nanotube Nucleation on Al
We present quantum chemical simulations demonstrating how single-walled carbon nanotubes (SWCNTs) form, or "nucleate", on the surface of Al2O3 nanoparticles during chemi... [more]
We present quantum chemical simulations demonstrating how single-walled carbon nanotubes (SWCNTs) form, or "nucleate", on the surface of Al2O3 nanoparticles during chemical vapor deposition (CVD) using CH4. SWCNT nucleation proceeds via the formation of extended polyyne chains that only interact with the catalyst surface at one or both ends. Consequently, SWCNT nucleation is not a surface-mediated process. We demonstrate that this unusual nucleation sequence is due to two factors. First, the p interaction between graphitic carbon and Al2O3 is extremely weak, such that graphitic carbon is expected to desorb at typical CVD temperatures. Second, hydrogen present at the catalyst surface actively passivates dangling carbon bonds, preventing a surface-mediated nucleation mechanism. The simulations reveal hydrogen's reactive chemical pathways during SWCNT nucleation and that the manner in which SWCNTs form on Al2O3 is fundamentally different from that observed using "traditional" transition metal catalysts. (Chemical Equation Presented).
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Nova |
2015 |
McLean B, Li H, Stefanovic R, Wood RJ, Webber GB, Ueno K, et al., 'Nanostructure of [Li (G4)] TFSI and [Li (G4)] NO 3 solvate ionic liquids at HOPG and Au (111) electrode interfaces as a function of potential', Physical Chemistry Chemical Physics, 17 325-333 (2015) [C1]
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Nova |
2015 |
Jiao M, Li K, Guan W, Wang Y, Wu Z, Page A, Morokuma K, 'Crystalline Ni
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Nova |
2015 |
Ahubelem N, Shah K, Moghtaderi B, Page AJ, 'Formation of benzofuran and chlorobenzofuran from 1,3-dichloropropene: A quantum chemical investigation', International Journal of Quantum Chemistry, 115 1739-1745 (2015) [C1]
We present a quantum chemical investigation of benzofuran and cholorobenzofuran formation mechanisms during the combustion of 1,3-dichloropropene. Density functional theory and Ga... [more]
We present a quantum chemical investigation of benzofuran and cholorobenzofuran formation mechanisms during the combustion of 1,3-dichloropropene. Density functional theory and Gaussian-n thermochemical methods are used to propose detailed mechanistic reaction pathways. These calculations indicate that oxidation of phenylvinyl radical intermediates and subsequent ring closure are key mechanistic pathways in the formation of benzofuran and chlorobenzofuran. Thermochemical and kinetic parameters presented herein will assist in further elucidation of dioxin formation mechanisms from thermolyses of hydrocarbon moieties.
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2015 |
Page AJ, Ding F, Irle S, Morokuma K, 'Insights into carbon nanotube and graphene formation mechanisms from molecular simulations: A review', Reports on Progress in Physics, 78 (2015) [C1]
The discovery of carbon nanotubes (CNTs) and graphene over the last two decades has heralded a new era in physics, chemistry and nanotechnology. During this time, intense efforts ... [more]
The discovery of carbon nanotubes (CNTs) and graphene over the last two decades has heralded a new era in physics, chemistry and nanotechnology. During this time, intense efforts have been made towards understanding the atomic-scale mechanisms by which these remarkable nanostructures grow. Molecular simulations have made significant contributions in this regard; indeed, they are responsible for many of the key discoveries and advancements towards this goal. Here we review molecular simulations of CNT and graphene growth, and in doing so we highlight the many invaluable insights gained from molecular simulations into these complex nanoscale self-assembly processes. This review highlights an often-overlooked aspect of CNT and graphene formation - that the two processes, although seldom discussed in the same terms, are in fact remarkably similar. Both can be viewed as a 0D¿1D¿2D transformation, which converts carbon atoms (0D) to polyyne chains (1D) to a complete sp2-carbon network (2D). The difference in the final structure (CNT or graphene) is determined only by the curvature of the catalyst and the strength of the carbon-metal interaction. We conclude our review by summarizing the present shortcomings of CNT/graphene growth simulations, and future challenges to this important area.
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Nova |
2015 |
Chung LW, Sameera WMC, Ramozzi R, Page AJ, Hatanaka M, Petrova GP, et al., 'The ONIOM Method and Its Applications.', Chem Rev, 115 5678-5796 (2015) [C1]
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Nova |
2014 |
Page AJ, Elbourne A, Stefanovic R, Addicoat MA, Warr GG, Voïtchovsky K, Atkin R, '3-Dimensional atomic scale structure of the ionic liquid-graphite interface elucidated by AM-AFM and quantum chemical simulations.', Nanoscale, 6 8100-8106 (2014) [C1]
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Nova |
2014 |
Jiao M, Qian H, Page A, Li K, Wang Y, Wu Z, et al., 'Graphene Nucleation from Amorphous Nickel Carbides: QM/MD Studies on the Role of Subsurface Carbon Density', JOURNAL OF PHYSICAL CHEMISTRY C, 118 11078-11084 (2014) [C1]
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2014 |
Addicoat MA, Stefanovic R, Webber GB, Atkin R, Page AJ, 'Assessment of the density functional tight binding method for protic ionic liquids', Journal of Chemical Theory and Computation, 10 4633-4643 (2014) [C1]
Density functional tight binding (DFTB), which is ~100-1000 times faster than full density functional theory (DFT), has been used to simulate the structure and properties of proti... [more]
Density functional tight binding (DFTB), which is ~100-1000 times faster than full density functional theory (DFT), has been used to simulate the structure and properties of protic ionic liquid (IL) ions, clusters of ions and the bulk liquid. Proton affinities for a wide range of IL cations and anions determined using DFTB generally reproduce G3B3 values to within 5-10 kcal/mol. The structures and thermodynamic stabilities of n-alkyl ammonium nitrate clusters (up to 450 quantum chemical atoms) predicted with DFTB are in excellent agreement with those determined using DFT. The IL bulk structure simulated using DFTB with periodic boundary conditions is in excellent agreement with published neutron diffraction data.
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Nova |
2014 |
Carstens T, Gustus R, Höfft O, Borisenko N, Endres F, Li H, et al., 'Combined STM, AFM, and DFT study of the highly ordered pyrolytic graphite/1-octyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide interface', Journal of Physical Chemistry C, 118 10833-10843 (2014) [C1]
The highly ordered pyrolytic graphite (HOPG)/1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([OMIm]Tf2N) interface is examined by ultrahigh vacuum scanning tunnelin... [more]
The highly ordered pyrolytic graphite (HOPG)/1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([OMIm]Tf2N) interface is examined by ultrahigh vacuum scanning tunneling microscopy (UHV-STM), atomic force microscopy (UHV-AFM) (and as a function of potential by in situ scanning tunneling microscopy (STM)), in situ atomic force microscopy (AFM), and density functional theory (DFT) calculations. In situ STM and AFM results reveal that multiple ionic liquid (IL) layers are present at the HOPG/electrode interface at all potentials. At open-circuit potential (OCP), attractions between the cation alkyl chain and the HOPG surface result in the ion layer bound to the surface being cation rich. As the potential is varied, the relative concentrations of cations and anions in the surface layer change: as the potential is made more positive, anions are preferentially adsorbed at the surface, while at negative potentials the surface layer is cation rich. At -2 V an unusual overstructure forms. STM images and AFM friction force microscopy measurements both confirm that the roughness of this overstructure increases with time. DFT calculations reveal that [OMIm]+ is attracted to the graphite surface at OCP; however, adsorption is enhanced at negative potentials due to favorable electrostatic interactions, and at -2 V the surface layer is cation rich and strongly bound. The energetically most favorable orientation within this layer is with the [OMIm]+ octyl chains aligned "epitaxially" along the graphitic lattice. This induces quasi-crystallization of cations on the graphite surface and formation of the overstructure. An alternative explanation may be that, because of the bulkiness of the cation sitting along the surface, a single layer of cations is unable to quench the surface potential, so a second layer forms. The most energetically favorable way to do this might be in a quasi-crystalline/multilayered fashion. It could also be a combination of strong surface binding/orientations and the need for multilayers to quench the charge. © 2014 American Chemical Society.
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Nova |
2014 |
Wang Y, Page AJ, Li H-B, Qian H-J, Jiao M-G, Wu Z-J, et al., 'Step-edge self-assembly during graphene nucleation on a nickel surface: QM/MD simulations', NANOSCALE, 6 140-144 (2014) [C1]
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Nova |
2014 |
Li HB, Page AJ, Hettich C, Aradi B, Köhler C, Frauenheim T, et al., 'Graphene nucleation on a surface-molten copper catalyst: Quantum chemical molecular dynamics simulations', Chemical Science, 5 3493-3500 (2014) [C1]
Chemical vapor deposition (CVD) growth of graphene on Cu(111) has been modeled with quantum chemical molecular dynamics (QM/MD) simulations. These simulations demonstrate at the a... [more]
Chemical vapor deposition (CVD) growth of graphene on Cu(111) has been modeled with quantum chemical molecular dynamics (QM/MD) simulations. These simulations demonstrate at the atomic level how graphene forms on copper surfaces. In contrast to other popular catalysts, such as nickel and iron, copper is in a surface molten state throughout graphene growth at CVD-relevant temperatures, and graphene growth takes place without subsurface diffusion of carbon. Surface Cu atoms have remarkably high mobilities on the Cu(111) surface, both before and after graphene nucleation. This surface mobility drives "defect healing" processes in the nucleating graphene structure that convert defects such as pentagons and heptagons into carbon hexagons. Consequently, the graphene defects that become "kinetically trapped" using other catalysts, such as Ni and Fe, are less commonly observed in the case of Cu. We propose this mechanism to be the basis of copper's ability to form high-quality, large-domain graphene flakes. © 2014 the Partner Organisations.
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Nova |
2013 |
Li HB, Page AJ, Irle S, Morokuma K, 'Temperature dependence of catalyst-free chirality-controlled single-walled carbon nanotube growth from organic templates', Journal of Physical Chemistry Letters, 4 3176-3180 (2013) [C1]
The temperature dependence of catalyst-free single-walled carbon nanotube (SWCNT) growth from organic molecular precursors is investigated using DFTB quantum chemical molecular dy... [more]
The temperature dependence of catalyst-free single-walled carbon nanotube (SWCNT) growth from organic molecular precursors is investigated using DFTB quantum chemical molecular dynamics simulations and DFT calculations. Growth of (6,6)-SWCNTs from [6]cycloparaphenylene ([6]CPP) template molecules was simulated at 300, 500, and 800 K using acetylene (C2H2) and ethynyl radicals (C2H) as growth agents. The highest growth rates were observed with C2H at 500 K. Higher temperatures lead to increased defect formation in the SWCNT structure during growth. Such defects, which cause the loss of SWCNT chirality control, were driven by radical addition reactions with inherently low kinetic barriers. We therefore propose that lower temperature is optimal for the C2H radical mechanism of SWCNT growth, and predict the existence of an optimum SWCNT growth temperature that balances the rates of growth and defect formation at a given C2H/C2H2 ratio. © 2013 American Chemical Society.
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Nova |
2013 |
Addicoat MA, Fukuoka S, Page AJ, Irle S, 'Stochastic Structure Determination for Conformationally Flexible Heterogenous Molecular Clusters: Application to Ionic Liquids', JOURNAL OF COMPUTATIONAL CHEMISTRY, 34 2591-2600 (2013) [C1]
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Nova |
2013 |
Page AJ, Chou C-P, Buu PQ, Witek H, Irle S, Morokuma K, 'Quantum chemical investigation of epoxide and ether groups in graphene oxide and their vibrational spectra', Physical Chemistry Chemical Physics, 15 3725-3735 (2013) [C1]
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Nova |
2013 |
Page AJ, Wang Y, Li H-B, Irle S, Morokuma K, 'Nucleation of Graphene Precursors on Transition Metal Surfaces: Insights from Theoretical Simulations', The Journal of Physical Chemistry Part C: Nanomaterials and Interfaces, 117 14858-14864 (2013) [C1]
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Nova |
2013 |
Chandrakumar KRS, Page AJ, Irle S, Morokuma K, 'Carbon Coating Precedes SWCNT Nucleation on Silicon Nanoparticles: Insights from QM/MD Simulations.', The Journal of Physical Chemistry Part C: Nanomaterials and Interfaces, 117 4238-4244 (2013) [C1]
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Nova |
2013 |
Li H-B, Page AJ, Irle S, Morokuma K, 'Revealing the Dual Role of Hydrogen for Growth Inhibition and Defect Healing in Polycyclic Aromatic Hydrocarbon Formation: QM/MD Simulations', Journal of Physical Chemistry Letters, 4 2323-2327 (2013) [C1]
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Nova |
2012 |
Kim J, Page AJ, Irle S, Morokuma K, 'Dynamics of Local Chirality during SWCNT Growth: Armchair versus Zigzag Nanotubes.', Journal of the American Chemical Society, 134 9311-9319 (2012) [C1]
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2012 |
Li H-B, Page AJ, Irle S, Morokuma K, 'SWCNT Growth from Chiral Carbon Nanorings: Prediction of Chirality and Diameter Influence on Growth Rates.', Journal of the American Chemical Society, 134 1588-1589 (2012) [C1]
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2012 |
Li H-B, Page AJ, Wang Y, Irle S, Morokuma K, 'Sub-Surface Nucleation of Graphene Precursors near a Ni(111) Step-Edge', Chemical Communications, 48 7937-7939 (2012) [C1]
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2012 |
Li H-B, Page AJ, Irle S, Morokuma K, 'Theoretical Insights into Chirality-Controlled SWCNT Growth from a Cycloparaphenylene Template.', ChemPhysChem: a European journal of chemical physics and physical chemistry, 13 1479-1485 (2012) [C1]
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2012 |
Addicoat M, Page AJ, Irle S, Morokuma K, Brain ZE, Flack L, 'Optimization of a genetic algorithm for the functionalization of fullerenes', Journal of Chemical Theory and Computation, 8 1841-1851 (2012) [C1]
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2012 |
Page AJ, Isomoto T, Knaup J, Irle S, Morokuma K, Morokuma K, 'Effects of molecular dynamics thermostats on descriptions of chemical nonequilibrium', Journal of Chemical Theory and Computation, 8 4019-4028 (2012) [C1]
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2011 |
Okamoto Y, Kawamura F, Ohta Y, Page AJ, Irle S, Morokuma K, 'Self-consistent-charge density-functional tight-binding/MD simulation of transition metal catalyst particle melting and carbide formation', Journal of Computational and Theoretical Nanoscience, 8 1755-1763 (2011)
Iron, nickel, and cobalt are commonly employed catalyst transition metals in catalytic chemical vapor deposition (CCVD) growth of SWCNTs. Quantum chemical molecular dynamics simul... [more]
Iron, nickel, and cobalt are commonly employed catalyst transition metals in catalytic chemical vapor deposition (CCVD) growth of SWCNTs. Quantum chemical molecular dynamics simulations (QM/MD) of transition metal particle melting and carbide formation during the early stage of singlewalled carbon nanotube (SWCNT) growth are presented here. The self-consistent-charge densityfunctional tight-binding (SCC-DFTB) method was employed as the potential for MD simulations over timescales of several hundreds of picoseconds at temperatures ranging from 400 K to 2000 K. Model systems consisting of 24C 2 molecules and a single C 30 'SWCNT cap-fragment' chemisorbed on the surface of transition metal clusters (Fe 38, Co 38, Ni 38) were employed. The melting behavior is compared with those of corresponding pristine transition metal clusters. Co displayed a larger tendency towards melting and 'bulk' carbide formation over the entire temperature range, whereas Fe and Ni clusters exhibited only surface carbide formation. Carbon surface diffusion was found for all metals, and the growth of carbon clusters by additional ring formation was observed in Fe/Ni trajectories at high temperatures, especially when high electronic temperature was employed. Although no sudden increase in Lindemann indices was observed clearly, we conclude that melting of Fe/Ni clusters starts at lower temperatures when carbon is present on the cluster, whereas the opposite trend is observed for Co clusters. Copyright © 2011 American Scientific Publishers.
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2011 |
Page AJ, Chandrakumar KRS, Irle S, Morokuma K, 'Do SiO2 and Carbon-Doped SiO2 Nanoparticles Melt? Insights from QM/MD Simulations, and Ramifications Regarding Carbon Nanotube Growth.', Chemical Physics Letters, 508 235-241 (2011) [C1]
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2011 |
Page AJ, Chandrakumar KRS, Irle S, Morokuma K, 'SWNT Nucleation From Carbon-Coated SiO2 Nanoparticles via a Vapor-Solid-Solid Mechanism.', Journal of the American Chemical Society, 133 621-628 (2011) [C1]
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2011 |
Wang Y, Page AJ, Nishimoto Y, Qian H-J, Irle S, Morokuma K, 'Template Effect in the Competition Between Haeckelite and Graphene Growth on Ni(111): Quantum Chemical Molecular Dynamics Simulations.', Journal of the American Chemical Society, 133 1883-1884 (2011) [C1]
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2011 |
Page AJ, Chandrakumar KRS, Irle S, Morokuma K, 'Thermal Annealing of SiC Nanoparticles Induces SWNT Nucleation: Evidence for a Catalyst- Independent SWNT Nucleation Mechanism.', Physical Chemistry Chemical Physics, 13 1567-1568 (2011) [C1]
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2010 |
Page AJ, Irle S, Morokuma K, 'Polyyne Extension and Ring Collapse Drives Ni-Catalyzed SWNT Growth: A QM/MD Investigation.', The Journal of Physical Chemistry Part C: Nanomaterials and Interfaces, 114 8206-8211 (2010) [C1]
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2010 |
Page AJ, Ohta Y, Irle S, Morokuma K, 'Mechanisms of Single-Walled Carbon Nanotube Nucleation, Growth and Healing Mechanisms Determined Using QM/MD Methods.', Accounts of Chemical Research, 43 1375-1385 (2010) [C1]
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2010 |
Page AJ, Yamane H, Ohta Y, Irle S, Morokuma K, 'QM/MD Simulation of SWNT Nucleation from Tansition-Metal Carbide Nanoparticles.', Journal of the American Chemical Society, 132 1569-1570 (2010) [C1]
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2010 |
Page AJ, Minami S, Ohta Y, Irle S, Morokuma K, 'Comparison of single-walled carbon nanotube growth from Fe and Ni nanoparticles using quantum chemical molecular dynamics methods', Carbon, 48 3014-3026 (2010) [C1]
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2010 |
Page AJ, Wilson DJD, Von Nagy-Felsobuki EI, 'Trends in MH2n+ ion-quadrupole complexes (M = Li, Be, Na, Mg, K,Ca; n = 1, 2) using ab initio methods', Physical Chemistry Chemical Physics, 12 13788-13797 (2010) [C1]
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Nova |
2009 |
Page AJ, Ohta Y, Irle S, Okamoto Y, Morokuma K, 'Defect Healing During Single-Walled Carbon Nanotube Growth: A Density-Functional Tight-Binding Molecular Dynamics Investigation.', The Journal of Physical Chemistry Part C: Nanomaterials and Interfaces, 113 2019-2020 (2009) [C1]
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2009 |
Ohto Y, Okamoto Y, Page AJ, Irle S, Morokuma K, 'Quantum Chemical Molecular Dynamics Simulation of Single-Wall Carbon Nanotube Cap Nucleation on an Iron Particle.', ACS Nano, 3 3413-3420 (2009) [C1]
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2009 |
Irle S, Ohta Y, Okamoto Y, Page AJ, Wang Y, Morokuma K, 'Milestone Molecular Dynamics Simulations of Single-Walled Carbon Nanotube Formation: A Brief Critical Review', Nano Research, 2 755-767 (2009) [C1]
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2009 |
Page AJ, Von Nagy-Felsobuki EI, 'Ab initio vibrational spectrum of ((2)Sigma(+))He-MgH2+', Chemical Physics Letters, 468 299-306 (2009) [C1]
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Nova |
2009 |
Page AJ, Moghtaderi B, 'Molecular dynamics simulation of the low-temperature partial oxidation of CH4', Journal of Physical Chemistry A, 113 1539-1547 (2009) [C1]
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Nova |
2009 |
Page AJ, Von Nagy-Felsobuki EI, 'Ab Initio rovibrational spectrum of the NaH2+ ion-quadrupole complex', Theoretical Chemistry Accounts, 122 87-100 (2009) [C1]
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Nova |
2008 |
Page AJ, Von Nagy-Felsobuki EI, 'Ab initio study of ground state MH2, HMHe+ and MHe22+, M=Mg, Ca', Physical Chemistry Chemical Physics, 10 1285-1291 (2008) [C1]
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Nova |
2008 |
Page AJ, Von Nagy-Felsobuki EI, 'Structural and energetic trends in Group-I and II hydrohelide cations', Chemical Physics Letters, 465 10-14 (2008) [C1]
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Nova |
2008 |
Page AJ, Von Nagy-Felsobuki EI, 'Trends in low-lying electronic states of XH2 (X = Li, Na, K)', Journal of Molecular Structure: THEOCHEM, 853 53-57 (2008) [C1]
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Nova |
2008 |
Page AJ, Von Nagy-Felsobuki EI, 'Ab initio electronic and rovibrational structure of MgH2/2+', Chemical Physics, 351 37-45 (2008) [C1]
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Nova |
2007 |
Page AJ, Von Nagy-Felsobuki EI, 'Rovibrational spectra of LiH2+, LiHD+ and LiD2+ determined from FCI property surfaces', Journal of Physical Chemistry A, 111 4478-4488 (2007) [C1]
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Nova |
2007 |
Page AJ, Wilson DJD, Von Nagy-Felsobuki EI, 'Ab initio calculations of the electronic structure of the ground states of HBeHe+ and BeHe22+', Chemical Physics Letters, 442 194-200 (2007) [C1]
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Nova |
2007 |
Page AJ, Von Nagy-Felsobuki EI, 'Ab Initio Rovibrational Spectra of BeH22+ BeHD2+ and BeD22+', Molecular Physics, 105 2527-2539 (2007) [C1]
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Nova |
2006 |
Page AJ, Wilson DJD, Von Nagy-Felsobuki EI, 'Ab initio properties and potential energy surface of the ground electronic state of BeHe2+', Chemical Physics Letters, 429 335-340 (2006) [C1]
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Nova |