Dr Jangmee Lee

Dr Jangmee Lee

Research Associate

School of Engineering

Career Summary

Biography

Jang Mee Lee received a B.S. degree in chemistry (2011), a M.S. degree (2013), and Ph. D degree (2018) in inorganic chemistry from Ewha Womans University (Korea). Her research focuses on the synthesis and characterization of 2-dimensional inorganic nanosheet-based nanohybrid for diverse applications such as photocatalysis, Li/Na-ion battery, and electrocatalysis. Especially, she is working on the in-situ XAS analysis to demonstrate the catalytic mechanism based on the local structure alteration of nano-crystalline material.

Qualifications

  • Doctor of Philosophy, EWHA Womans University, Korea

Keywords

  • Energy Conversion and Storage
  • Hybrid architecture
  • Low-dimensional Nanomaterials

Languages

  • Korean (Mother)
  • English (Fluent)

Fields of Research

Code Description Percentage
091202 Composite and Hybrid Materials 40
091305 Energy Generation, Conversion and Storage Engineering 30
100708 Nanomaterials 30

Professional Experience

UON Appointment

Title Organisation / Department
Research Associate University of Newcastle
School of Engineering
Australia

Academic appointment

Dates Title Organisation / Department
1/03/2018 - 16/11/2018 Postdoctor Ewha Womans University
Department of Chemistry and Nanoscience
Korea, Republic of
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Publications

For publications that are currently unpublished or in-press, details are shown in italics.


Journal article (33 outputs)

Year Citation Altmetrics Link
2019 Lee JM, Hwang S-J, 'Remarkable influence of the local symmetry of substituted 3d metal ion on bifunctional electrocatalyst performance of alpha-MnO2 nanowire', JOURNAL OF SOLID STATE CHEMISTRY, 269 354-360 (2019)
DOI 10.1016/j.jssc.2018.10.009
2019 Son S, Lee JM, Kim S-J, Kim H, Jin X, Wang KK, et al., 'Understanding the relative efficacies and versatile roles of 2D conductive nanosheets in hybrid-type photocatalyst', APPLIED CATALYSIS B-ENVIRONMENTAL, 257 (2019)
DOI 10.1016/j.apcatb.2019.117875
2019 Lee JM, Kang B, Jo YK, Hwang S-J, 'Organic Intercalant-Free Liquid Exfoliation Route to Layered Metal-Oxide Nanosheets via the Control of Electrostatic Interlayer Interaction', ACS APPLIED MATERIALS & INTERFACES, 11 12121-12132 (2019)
DOI 10.1021/acsami.9b00566
2019 Lim J, Lee JM, Kim C, Hwang S-J, Lee J, Choi W, 'Two-dimensional RuO2 nanosheets as robust catalysts for peroxymonosulfate activation', ENVIRONMENTAL SCIENCE-NANO, 6 2084-2093 (2019)
DOI 10.1039/c9en00500e
Citations Web of Science - 1
2019 Cha W, Kim IY, Lee JM, Kim S, Ramadass K, Gopalakrishnan K, et al., 'Sulfur-Doped Mesoporous Carbon Nitride with an Ordered Porous Structure for Sodium-Ion Batteries.', ACS Appl Mater Interfaces, 11 27192-27199 (2019) [C1]
DOI 10.1021/acsami.9b07657
Citations Scopus - 1Web of Science - 1
Co-authors Ajayan Vinu, Inyoung Kim, Kavitha Ramadass
2019 Singh G, Ramadass K, Lee JM, Ismail IS, Singh M, Bansal V, et al., 'Convenient design of porous and heteroatom self-doped carbons for CO2 capture', Microporous and Mesoporous Materials, 287 1-8 (2019) [C1]
DOI 10.1016/j.micromeso.2019.05.042
Citations Scopus - 4Web of Science - 3
Co-authors Kavitha Ramadass, Jaehun Yang, Ajayan Vinu
2018 Gu T-H, Agyeman DA, Shin S-J, Jin X, Lee JM, Kim H, et al., 'alpha-MnO2 Nanowire-Anchored Highly Oxidized Cluster as a Catalyst for Li-O-2 Batteries: Superior Electrocatalytic Activity and High Functionality', ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 57 15984-15989 (2018)
DOI 10.1002/anie.201809205
Citations Web of Science - 16
2018 Kim IY, Lee JM, Hwang EH, Pei YR, Jin WB, Choy JH, Hwang SJ, 'Correction: Water-floating nanohybrid films of layered titanate-graphene for sanitization of algae without secondary pollution (RSC Advances (2016) 6 (98528-98535) DOI: 10.1039/C6RA24140A)', RSC Advances, 8 18109 (2018)

© 2018 The Royal Society of Chemistry. In the published paper, the affiliations of Eui-Ho Hwang and Woo-Bin Jin were wrongly designated, and the corrected version is shown below. ... [more]

© 2018 The Royal Society of Chemistry. In the published paper, the affiliations of Eui-Ho Hwang and Woo-Bin Jin were wrongly designated, and the corrected version is shown below. The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.

DOI 10.1039/c8ra90039f
Co-authors Inyoung Kim
2018 Lee JM, Yang J-H, Kwon NH, Jo YK, Choy J-H, Hwang S-J, 'Intercalative hybridization of layered double hydroxide nanocrystals with mesoporous g-C3N4 for enhancing visible light-induced H-2 production efficiency', DALTON TRANSACTIONS, 47 2949-2955 (2018)
DOI 10.1039/c7dt03466k
Citations Scopus - 5Web of Science - 5
Co-authors Jaehun Yang
2017 Oh J, Lee JM, Yoo Y, Kim J, Hwang S-J, Park S, 'New insight of the photocatalytic behaviors of graphitic carbon nitrides for hydrogen evolution and their associations with grain size, porosity, and photophysical properties', APPLIED CATALYSIS B-ENVIRONMENTAL, 218 349-358 (2017)
DOI 10.1016/j.apcatb.2017.06.067
Citations Web of Science - 29
2017 Lim J, Lee JM, Park B, Jin X, Hwang S-J, 'Homogeneous cationic substitution for two-dimensional layered metal oxide nanosheets via a galvanic exchange reaction', NANOSCALE, 9 792-801 (2017)
DOI 10.1039/c6nr08614d
Citations Web of Science - 5
2017 Oh SM, Kim IY, Patil SB, Park B, Lee JM, Adpakpang K, et al., 'Improvement of na ion electrode activity of metal oxide via composite formation with metal sulfide', ACS Applied Materials and Interfaces, 9 2249-2260 (2017)

© 2016 American Chemical Society. The composite formation with a conductive metal sulfide domain can provide an effective methodology to improve the Na-ion electrode functionality... [more]

© 2016 American Chemical Society. The composite formation with a conductive metal sulfide domain can provide an effective methodology to improve the Na-ion electrode functionality of metal oxide. The heat treatment of TiO2(B) under CS2 flow yields an intimately coupled TiO2(B)-TiS2 nanocomposite with intervened TiS2 domain, since the reaction between metal oxide and CS2 leads to the formation of metal sulfide and CO2. The negligible change in lattice parameters and significant enhancement of visible light absorption upon the reaction with CS2 underscore the formation of conductive metal sulfide domains. The resulting TiO2(B)-TiS2 nanocomposites deliver greater discharge capacities with better rate characteristics for electrochemical sodiation-desodiation process than does the pristine TiO2(B). The 23Na magic angle spinning nuclear magnetic resonance analysis clearly demonstrates that the electrode activities of the present nanocomposites rely on the capacitive storage of Na+ ions, and the TiS2 domains in TiO2(B)-TiS2 nanocomposites play a role as mediators for Na+ ions to and from TiO2(B) domains. According to the electrochemical impedance spectroscopy, the reaction with CS2 leads to the significant enhancement of charge transfer kinetics, which is responsible for the accompanying improvement in electrode performance. The present study provides clear evidence for the usefulness in composite formation between the semiconducting metal oxide and metal sulfide in exploring new efficient NIB electrode materials.

DOI 10.1021/acsami.6b11220
Citations Scopus - 4Web of Science - 4
Co-authors Inyoung Kim
2016 Lee JM, Mok EK, Lee S, Lee N-S, Debbichi L, Kim H, Hwang S-J, 'A Conductive Hybridization Matrix of RuO2 Two-Dimensional Nanosheets: A Hybrid-Type Photocatalyst', ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 55 8546-8550 (2016)
DOI 10.1002/anie.201601494
Citations Web of Science - 20
2016 Lee JM, Gu TH, Kwon NH, Oh SM, Hwang S-J, 'Rapid Synthetic Route to Nanocrystalline Carbon-Mixed Metal Oxide Nanocomposites with Enhanced Electrode Functionality', JOURNAL OF PHYSICAL CHEMISTRY C, 120 8451-8460 (2016)
DOI 10.1021/acs.jpcc.6b00841
Citations Web of Science - 6
2016 Gunjakar JL, Jo YK, Kim IY, Lee JM, Patil SB, Pyun JC, Hwang SJ, 'A chemical bath deposition route to facet-controlled Ag

© 2016 Published by Elsevier Inc. A facile, economic, and reproducible chemical bath deposition (CBD) method is developed for the fabrication of facet-controlled Ag3PO4 thin films... [more]

© 2016 Published by Elsevier Inc. A facile, economic, and reproducible chemical bath deposition (CBD) method is developed for the fabrication of facet-controlled Ag3PO4 thin films with enhanced visible light photocatalytic activity. The fine-control of bath temperature, precursor, complexing agent, substrate, and solution pH is fairly crucial in preparing the facet-selective thin film of Ag3PO4 nanocrystal. The change of precursor from silver nitrate to silver acetate makes possible the tailoring of the crystal shape of Ag3PO4 from cube to rhombic dodecahedron and also the bandgap tuning of the deposited films. The control of [Ag+]/[phosphate] ratio enables to maximize the loading amount of Ag3PO4 crystals per the unit area of the deposited film. All the fabricated Ag3PO4 thin films show high photocatalytic activity for visible light-induced degradation of organic molecules, which can be optimized by tailoring the crystal shape of the deposited crystals. This CBD method is also useful in preparing the facet-controlled hybrid film of Ag3PO4-ZnO photocatalyst. The present study clearly demonstrates the usefulness of the present CBD method for fabricating facet-controlled thin films of metal oxosalt and its nanohybrid.

DOI 10.1016/j.jssc.2016.05.028
Citations Scopus - 10Web of Science - 10
Co-authors Inyoung Kim
2016 Lee JM, Kwon NH, Kim IY, Hwang SJ, 'A vapor-phase carbon-deposition route to efficient inorganic nanosheet-based electrodes', Materials Letters, 179 217-221 (2016)

© 2016 Elsevier B.V. Efficient inorganic nanosheet-based electrode materials can be synthesized by the calcination of exfoliated Ti5NbO14 nanosheets under C2H2 flow. While the cal... [more]

© 2016 Elsevier B.V. Efficient inorganic nanosheet-based electrode materials can be synthesized by the calcination of exfoliated Ti5NbO14 nanosheets under C2H2 flow. While the calcination in Ar atmosphere causes a phase transformation from layered Ti5NbO14 to TiO2 and Nb2O5, employing C2H2 atmosphere leads to the maintenance of the original layered structure of Ti5NbO14 upon the heat-treatment, which is attributable to the stabilization of layered lattice by surface passivation by deposited carbon layer. The resulting carbon@titanoniobate materials show mesoporous house-of-cards-type stacking structure of 2D nanosheets. This carbon@titanoniobate material delivers large discharge capacity of ~320¿mA¿h¿g-1 with excellent cyclability and rate performance, which is much superior to that of carbon-free homologue. The present study clearly demonstrates that the heat-treatment under C2H2 flow provides a simple and effective route to high-performance inorganic nanosheet-based electrode materials.

DOI 10.1016/j.matlet.2016.05.021
Citations Scopus - 1Web of Science - 1
Co-authors Inyoung Kim
2016 Kim IY, Lee JM, Hwang EH, Pei YR, Jin WB, Choy JH, Hwang SJ, 'Water-floating nanohybrid films of layered titanate-graphene for sanitization of algae without secondary pollution', RSC Advances, 6 98528-98535 (2016)

© 2016 Royal Society of Chemistry. A novel efficient and safe methodology to sanitize algae in natural water without secondary pollution is developed by fabricating floating graph... [more]

© 2016 Royal Society of Chemistry. A novel efficient and safe methodology to sanitize algae in natural water without secondary pollution is developed by fabricating floating graphene-inorganic hybrid films. Two kinds of floating freestanding hybrid films of layered titanate-graphene with efficient algae-killing functionality are fabricated by vacuum-assisted filtration of mixed colloidal suspensions of reduced graphene oxide (rG-O) nanosheets and exfoliated layered titanate nanosheets. Both the titanate nanosheets with lepidocrocite- and trititanate-type structures form homogeneous colloidal mixtures and hybrid freestanding films with rG-O nanosheets. The incorporation of a layered titanate nanosheet enhances the algae-killing activity of the graphene freestanding film, highlighting the beneficial role of photocatalytically-active titanate nanosheet. In comparison to the trititanate nanosheet, the lepidocrocite-type titanate nanosheet is more effective as a building block for enhancing the algae-killing activity of graphene film and for forming a novel nanoblade structure on the surface of the graphene film. The observed high sterilization functionality of the present layered titanate-graphene hybrid films is attributable to both the formation of the novel sharp nanoblade structure and the photocatalytic activity of layered titanate. The present result underscores that hybridization between graphene and photocatalytically-active inorganic nanosheets can provide a powerful way to explore pollution-free recoverable matrix efficient for removing harmful microorganisms in natural water.

DOI 10.1039/c6ra24140a
Citations Scopus - 4Web of Science - 6
Co-authors Inyoung Kim
2015 Lee JM, Jin HB, Kim IY, Jo YK, Hwang JW, Wang KK, et al., 'A Crucial Role of Rh Substituent Ion in Photoinduced Internal Electron Transfer and Enhanced Photocatalytic Activity of CdS-Ti

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. The photocatalytic activity and photostability of CdS quantum dot (QD) can be remarkably enhanced by hybridization with Rh... [more]

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. The photocatalytic activity and photostability of CdS quantum dot (QD) can be remarkably enhanced by hybridization with Rh-substituted layered titanate nanosheet even at very low Rh substitution rate (<1%). Mesoporous CdS-Ti(5.2-x)/6Rhx/2O2 nanohybrids are synthesized by a self-assembly of exfoliated Ti(5.2-x)/6Rhx/2O2 nanosheets with CdS QDs. The partial substitution of Rh3+/Rh4+ ions for Ti4+ ions in layered titanate is quite effective in enhancing an electronic coupling between hybridized CdS and titanate components via the formation of interband Rh 4d states. A crucial role of Rh substituent ion in the internal electron transfer is obviously evidenced from in situ X-ray absorption spectroscopy showing the elongation of (RhO) bond under visible light irradiation. This is the first spectroscopic evidence for the important role of substituent ion in the photoinduced electron transfer of hybrid-type photocatalyst. The CdS-Ti(5.2-x)/6Rhx/2O2 nanohybrids show much higher photocatalytic activity for H2 production and better photostability than do CdS and unsubstituted CdS-TiO2 nanohybrid. This result is ascribable to the enhancement of visible light absorptivity, the depression of electron-hole recombination, and the enhanced hole curing of CdS upon Rh substitution. The present study underscores that the hybridization with composition-controlled inorganic nanosheet provides a novel efficient methodology to optimize the photo-related functionalities of semiconductor nanocrystal.

DOI 10.1002/smll.201501806
Citations Scopus - 9Web of Science - 10
Co-authors Inyoung Kim
2015 Patil SB, Adpakpang K, Oh SM, Lee JM, Hwang S-J, 'Reductive hybridization route with exfoliated graphene oxide and MoS2 nanosheets to efficient electrode materials', ELECTROCHIMICA ACTA, 176 188-196 (2015)
DOI 10.1016/j.electacta.2015.06.133
Citations Web of Science - 11
2015 Gu TH, Gunjakar JL, Kim IY, Patil SB, Lee JM, Jin X, et al., 'Porous Hybrid Network of Graphene and Metal Oxide Nanosheets as Useful Matrix for Improving the Electrode Performance of Layered Double Hydroxides', Small, 11 3921-3931 (2015)

© 2015 WILEY-VCH Verlag GmbH &amp; Co. KGaA, Weinheim. Mesoporous hybrid network of reduced graphene oxide (rG-O) and layered MnO&lt;inf&gt;2&lt;/inf&gt; nanosheets could act as... [more]

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Mesoporous hybrid network of reduced graphene oxide (rG-O) and layered MnO<inf>2</inf> nanosheets could act as an efficient immobilization matrix for improving the electrochemical activity of layered double hydroxide (LDH). The control of MnO<inf>2</inf>/rG-O ratio is crucial in optimizing the porous structure and electrical conductivity of the resulting hybrid structure. The immobilization of Co-Al-LDH on hybrid MnO<inf>2</inf>/rG-O network is more effective in enhancing its electrode activity compared with that of on pure rG-O network. The Co-Al-LDH-rG-O-MnO<inf>2</inf> nanohybrid deliveres a greater specific capacitance than does MnO<inf>2</inf>-free Co-Al-LDH-rG-O nanohybrid. The beneficial effect of MnO<inf>2</inf> incorporation on the electrode performance of nanohybrid is more prominent for higher current density and faster scan rate, underscoring the significant enhancement of the electron transport of Co-Al-LDH-rG-O. This is supported by electrochemical impedance spectroscopy. The present study clearly demonstrates the usefulness of the porously assembled hybrid network of graphene and metal oxide nanosheets as an effective platform for exploring efficient LDH-based functional materials.

DOI 10.1002/smll.201500286
Citations Scopus - 25Web of Science - 25
Co-authors Inyoung Kim
2014 Lee JM, Gunjakar JL, Ham Y, Kim IY, Domen K, Hwang S-J, 'A Linker-Mediated Self-Assembly Method to Couple Isocharged Nanostructures: Layered Double Hydroxide-CdS Nanohybrids with High Activity for Visible-Light-Induced H-2 Generation', CHEMISTRY-A EUROPEAN JOURNAL, 20 17004-17010 (2014)
DOI 10.1002/chem.201404472
Citations Web of Science - 20
Co-authors Inyoung Kim
2014 Jo YK, Kim IY, Lee JM, Nahm S, Choi JW, Hwang SJ, 'Surface-anchored CdS@Ag

The surface anchoring of CdS on the surface of Ag3PO4 nanoparticle is achieved by an electrostatically-derived assembly between negatively-charged Ag3PO4 nanoparticles and positiv... [more]

The surface anchoring of CdS on the surface of Ag3PO4 nanoparticle is achieved by an electrostatically-derived assembly between negatively-charged Ag3PO4 nanoparticles and positively-charged CdS quantum dots (QDs). The composite formation between Ag3PO4 and CdS nanoparticles gives rise not only to an enhancement of visible light absorption but also to a notable depression of photoluminescence signal, confirming the strong electronic coupling between the two components. The present CdS@Ag3PO4 nanocomposite displays higher visible light photocatalytic activity than do the precursors Ag3PO4 and CdS, demonstrating the usefulness of electrostatically-derived assembly in exploring highly efficient photocatalyst material. © 2013 Published by Elsevier B.V.

DOI 10.1016/j.matlet.2013.09.091
Citations Scopus - 31Web of Science - 31
Co-authors Inyoung Kim
2014 Jo YK, Kim IY, Gunjakar JL, Lee JM, Lee NS, Lee SH, Hwang SJ, 'Unique properties of 2 D layered titanate nanosheets as a building block for the optimization of the photocatalytic activity and photostability of TiO

In comparison with the hybridization with 0D TiO2 nanoparticle, 2D layered TiO2 nanosheets are much more effective in the improvement of the photocatalytic activity and photostabi... [more]

In comparison with the hybridization with 0D TiO2 nanoparticle, 2D layered TiO2 nanosheets are much more effective in the improvement of the photocatalytic activity and photostability of semiconducting compounds. The 2D TiO2-Ag3PO4 nanohybrid described in this paper shows a greater decrease in the electron-hole recombination upon hybridization and a stronger chemical interaction between the components than the 0D homologue. This result confirms the benefits of 2D layered TiO 2 nanosheets as a building block for efficient hybrid-type photocatalyst materials. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DOI 10.1002/chem.201402726
Citations Scopus - 16Web of Science - 19
Co-authors Inyoung Kim
2014 Park S, Lee JM, Jo YK, Kim IY, Hwang SJ, 'A facile exfoliation-crystal growth route to multicomponent Ag

Multicomponent Ag2CO3/Ag-layered Ti 5NbO14 nanohybrids are synthesized by the crystal growth of silver carbonate on the surface of exfoliated layered titanoniobate 2D nanosheets. ... [more]

Multicomponent Ag2CO3/Ag-layered Ti 5NbO14 nanohybrids are synthesized by the crystal growth of silver carbonate on the surface of exfoliated layered titanoniobate 2D nanosheets. In the obtained nanohybrids, the spherical Ag2CO 3 nanoparticles with a size of 5-10 nm are immobilized on the surface of the titanoniobate nanosheets with partial formation of neutral Ag metal caused by electron transfer from anionic titanoniobate nanosheets to silver cations. An electronic coupling between Ag2CO3/Ag and Ti5NbO14 nanosheets leads to a remarkable enhancement of visible light absorption and a significant depression of electron-hole recombination. The present Ag2CO3/Ag-layered Ti 5NbO14 nanohybrids show much higher visible light photocatalytic activity than the unhybridized Ag2CO3, underscoring the beneficial effect of hybridization with metal oxide nanosheets on the photocatalytic activity of silver oxosalts. Before and after the photoreaction, the crystal structure and crystal morphology of the Ag 2CO3/Ag-layered Ti5NbO14 nanohybrids remain unchanged, highlighting the excellent photostability of these materials. All the present experimental findings clearly demonstrate the usefulness of the exfoliation-crystal growth method in exploring novel efficient visible light active photocatalysts. This journal is © the Partner Organisations 2014.

DOI 10.1039/c4dt00018h
Citations Scopus - 15Web of Science - 17
Co-authors Inyoung Kim
2014 Gunjakar JL, Kim IY, Lee JM, Jo YK, Hwang SJ, 'Exploration of nanostructured functional materials based on hybridization of inorganic 2D nanosheets', Journal of Physical Chemistry C, 118 3847-3863 (2014)

The 2D nanosheets of layered inorganic solids prepared by soft-chemical exfoliation reaction can be used as effective building blocks for hybridization with inorganic, organic, bi... [more]

The 2D nanosheets of layered inorganic solids prepared by soft-chemical exfoliation reaction can be used as effective building blocks for hybridization with inorganic, organic, bio-, and polymer molecules/nanostructures. In comparison with graphene nanosheets, the 2D inorganic nanosheets boast much higher tunability in their chemical composition and physicochemical properties, leading to the creation of unexpected novel functionalities upon hybridization. Despite such unique and intriguing advantages of inorganic nanosheets, there are still only limited numbers of studies regarding the inorganic nanosheet-based hybrid materials. This Feature Article focuses on fundamental aspects of diverse synthetic strategies of the 2D nanosheet-based nanohybrids such as electrostatically derived reassembling, layer-by-layer deposition, crystal growth on the surface sites of nanosheets, and so on. Also, diverse functionalities of these 2D nanohybrid materials are discussed with an emphasis on the energy and environmental applications such as Li-ion batteries, supercapacitors, photocatalysts, fuel cells, and greenhouse gas capture. A prospect for the exploration of novel inorganic 2D nanosheet-based functional materials is provided along with new strategies to optimize the functionality of 2D inorganic nanosheets and their nanohybrids. © 2014 American Chemical Society.

DOI 10.1021/jp410626y
Citations Scopus - 78Web of Science - 82
Co-authors Inyoung Kim
2014 Kim IY, Jo YK, Lee JM, Wang L, Hwang SJ, 'Unique advantages of exfoliated 2D nanosheets for tailoring the functionalities of nanocomposites', Journal of Physical Chemistry Letters, 5 4149-4161 (2014)

© 2014 American Chemical Society. Hybridization with exfoliated two-dimensional (2D) nanosheets provides a very effective and powerful way not only to control the physicochemical ... [more]

© 2014 American Chemical Society. Hybridization with exfoliated two-dimensional (2D) nanosheets provides a very effective and powerful way not only to control the physicochemical properties of hybridized species but also to explore nanocomposites with novel functionalities. Deliberate coupling between the hybridized species is critically important in maximizing the effect of hybridization on the physicochemical properties and functionality of hybridized components. The very small thickness and extremely large surface of exfoliated 2D nanosheets render these materials ideal candidates for achieving a strong coupling with diverse guest species. This Perspective focuses on the unique characteristics of exfoliated 2D nanosheets as building blocks for designing hybrid materials. Several intriguing examples of strong interaction between exfoliated 2D nanosheets and hybridized species are summarized with an emphasis on the effective control of electronic, optical, structural, and morphological characteristics. An outlook on the future research directions is provided along with new strategies to maximize the coupling in the 2D nanosheet-based hybrid materials.

DOI 10.1021/jz502038g
Citations Scopus - 60Web of Science - 62
Co-authors Inyoung Kim
2013 Jo KY, Han SY, Lee JM, Kim IY, Nahm S, Choi JW, Hwang SJ, 'Remarkable enhancement of the electrode performance of nanocrystalline LiMn

A facile solvothermal way to immobilize nanocrystalline LiMn 2O4 on the surface of graphene nanosheets is developed to improve the functionality of lithium manganate as lithium in... [more]

A facile solvothermal way to immobilize nanocrystalline LiMn 2O4 on the surface of graphene nanosheets is developed to improve the functionality of lithium manganate as lithium intercalation electrode. A solvothermal treatment for the colloidal mixture of graphene oxide (GO) nanosheets and LiMn2O4 nanocrystals gives rise not only to the reduction of GO to reduced graphene oxide (RGO) but also to the immobilization of lithium manganate nanoparticles on the surface of RGO nanosheets. According to powder X-ray diffraction and electron microscopic analyses, the crystal structure and morphology of spinel lithium manganate remain intact upon the composite formation with the RGO nanosheets. The application of larger aldehyde molecule as a reductant leads to the increase of crystallinity and the lowering of Mn oxidation state for the pristine LiMn 2O4 and its nanocomposite with the RGO nanosheets. The present LiMn2O4-RGO nanocomposites display promising cathode performances for lithium rechargeable batteries, which are much superior to those of the pristine LiMn2O4 nanocrystals. The observed enhancement of electrode performance upon the composite formation with the RGO nanosheets is attributable both to the improvement of the surface ion transport of nanocrystalline lithium manganate and to the increase of electrical conductivity. The present experimental findings demonstrate that the solvothermal treatment with RGO nanosheets provides an effective way of improving the electrochemical activity of nanocrystalline lithium metal oxides. © 2013 Elsevier Ltd.

DOI 10.1016/j.electacta.2013.01.022
Citations Scopus - 19Web of Science - 17
Co-authors Inyoung Kim
2013 Shin SI, Go A, Kim IY, Lee JM, Lee Y, Hwang SJ, 'A beneficial role of exfoliated layered metal oxide nanosheets in optimizing the electrocatalytic activity and pore structure of Pt-reduced graphene oxide nanocomposites', Energy and Environmental Science, 6 608-617 (2013)

Mesoporous nanocomposites of Pt-reduced graphene oxide (RGO)-layered titanate are synthesized by the reaction of a mixture of exfoliated layered titanate nanosheets, graphene oxid... [more]

Mesoporous nanocomposites of Pt-reduced graphene oxide (RGO)-layered titanate are synthesized by the reaction of a mixture of exfoliated layered titanate nanosheets, graphene oxide nanosheets, and H<inf>2</inf>PtCl <inf>6</inf> with NaBH<inf>4</inf> to investigate the effect of layered metal oxide nanosheets on the electrocatalyst performance of Pt-RGO nanocomposites. The obtained ternary nanocomposites are composed of a porous stacking assembly of layered titanate/RGO nanosheets with well-dispersed Pt nanocrystals whose particle size becomes smaller with the increase of titanate content. The incorporation of layered titanate nanosheets into the Pt-RGO nanocomposite induces a marked increase of surface area through the frustration of a strong p-p interaction between RGO nanosheets by the intervention of titanate nanosheets. In addition, the incorporation of layered titanate nanosheets gives rise to a remarkable improvement of electrocatalytic activity for oxygen reduction reaction (ORR). Of prime importance is that the present nanocomposites show a more positive onset potential for ORR than commercial Pt/carbon catalysts, underscoring a powerful role of titanate nanosheets in optimizing the electrocatalyst performance of Pt-RGO nanocomposites. This is the first report showing the usefulness of metal oxide nanosheets as an effective additive for enhancing the electrocatalyst performance of platinum nanoparticles. The observed enhancement of electrocatalytic activity upon the addition of titanate nanosheets is attributable to the decrease of Pt crystal size, the increase of surface area, and the increase of surface hydrophilicity. The present findings clearly demonstrate that the incorporation of layered titanate nanosheets is quite effective in improving the electrocatalytic functionality of Pt-RGO nanocomposites. © The Royal Society of Chemistry 2013.

DOI 10.1039/c2ee22739h
Citations Scopus - 48Web of Science - 51
Co-authors Inyoung Kim
2013 Gunjakar JL, Kim IY, Lee JM, Lee NS, Hwang SJ, 'Self-assembly of layered double hydroxide 2D nanoplates with graphene nanosheets: An effective way to improve the photocatalytic activity of 2D nanostructured materials for visible light-induced O

Highly efficient photocatalysts for visible light-induced O2 generation are synthesized via an electrostatically derived self-assembly of Zn-Cr-LDH 2D nanoplates with graphene 2D ... [more]

Highly efficient photocatalysts for visible light-induced O2 generation are synthesized via an electrostatically derived self-assembly of Zn-Cr-LDH 2D nanoplates with graphene 2D nanosheets. In the obtained nanohybrids, the positively charged Zn-Cr-LDH nanoplates are immobilized on the surface of negatively charged graphene nanosheets with the formation of a highly porous stacked structure. A strong electronic coupling of the subnanometer-thick Zn-Cr-LDH nanoplates with reduced graphene oxide (RGO)/graphene oxide (GO) nanosheets gives rise not only to the prominent increase of visible light absorption but also to a remarkable depression of the photoluminescence signal. The self-assembled Zn-Cr-LDH-RGO nanohybrids display an unusually high photocatalytic activity for visible light-induced O 2 generation with a rate of ~1.20 mmol h-1 g -1, which is far superior to that of the pristine Zn-Cr-LDH material (~0.67 mmol h-1 g-1). The fact that pristine Zn-Cr-LDH is one of the most effective visible light photocatalysts for O2 production with unusually high quantum efficiency of 61% at ¿ = 410 nm highlights the excellent functionality of the Zn-Cr-LDH-RGO nanohybrids as visible light active photocatalysts. The Zn-Cr-LDH-RGO nanohybrid shows a higher photocatalytic activity than the Zn-Cr-LDH-GO nanohybrid, providing strong evidence for the superior advantage of the hybridization with RGO. The present findings clearly demonstrate that graphene nanosheets can be used as an effective platform for improving the photocatalytic activity of 2D nanostructured inorganic solids. © 2013 The Royal Society of Chemistry.

DOI 10.1039/c3ee23989f
Citations Scopus - 146Web of Science - 142
Co-authors Inyoung Kim
2013 Gunjakar JL, Kim TW, Kim IY, Lee JM, Hwang SJ, 'Highly efficient visible light-induced O

Unusually high photocatalytic activity of visible light-induced O2 generation can be achieved by electrostatically-derived self-Assembly between exfoliated Zn-Cr-LDH 2D nanosheets... [more]

Unusually high photocatalytic activity of visible light-induced O2 generation can be achieved by electrostatically-derived self-Assembly between exfoliated Zn-Cr-LDH 2D nanosheets and POM 0D nanoclusters (W7O24 62 and V10O28 62) acting as an electron acceptor. This self-Assembly can provide a high flexibility in the control of the chemical composition and pore structure of the resulting LDH-based nanohybrids. The hybridization with POM nanoclusters remarkably enhances the photocatalytic activity of the pristine Zn-Cr-LDH, which is attributable to the formation of porous structure and depression of charge recombination. Of prime interest is that the excellent photocatalytic activity of the as-prepared Zn-Cr-LDH-POM nanohybrid for visible light-induced O2 generation can be further enhanced by calcination at 200 6C, leading to the very high apparent quantum yield of ,75.2% at 420 nm. The present findings clearly demonstrate that the self-Assembly of LDH-POM is fairly powerful in synthesizing novel LDH-based porous nanohybrid photocatalyst for visible light-induced O2 generation.

DOI 10.1038/srep02080
Citations Scopus - 34Web of Science - 36
Co-authors Inyoung Kim
2012 Lee YR, Kim IY, Kim TW, Lee JM, Hwang SJ, 'Mixed colloidal suspensions of reduced graphene oxide and layered metal oxide nanosheets: Useful precursors for the porous nanocomposites and hybrid films of graphene/metal oxide', Chemistry - A European Journal, 18 2263-2271 (2012)

Homogeneously mixed colloidal suspensions of reduced graphene oxide, or RGO, and layered manganate nanosheets have been synthesized by a simple addition of the exfoliated colloid ... [more]

Homogeneously mixed colloidal suspensions of reduced graphene oxide, or RGO, and layered manganate nanosheets have been synthesized by a simple addition of the exfoliated colloid of RGO into that of layered MnO 2. The obtained mixed colloidal suspensions with the RGO/MnO 2 ratio of =0.3 show good colloidal stability without any phase separation and a negatively charged state with a zeta (¿) potential of -30 to -40 mV. The flocculation of these mixed colloidal suspensions with lithium cations yields porous nanocomposites of Li/RGO-layered MnO 2 with high electrochemical activity and a markedly expanded surface area of around 70-100 m 2 g -1. Relative to the Li/RGO and Li/layered MnO 2 nanocomposites (¿116 and ¿167 F g -1), the obtained Li/RGO-layered MnO 2 nanocomposites deliver a larger capacitance of approximately 210 F g -1 with good cyclability of around 95-97 % up to the 1000th cycle, thus indicating the positive effect of hybridization on the electrode performances of RGO and lithium manganate. Also, an electrophoretic deposition of the mixed colloidal suspensions makes it possible to easily fabricate uniform hybrid films composed of graphene and manganese oxide. The obtained films show a distinct electrochemical activity and a homogeneous distribution of RGO and MnO 2. The present experimental findings clearly demonstrate that the utilization of the mixed colloidal suspensions as precursors provides a facile and universal methodology to synthesize various types of graphene/metal oxide hybrid materials. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DOI 10.1002/chem.201102646
Citations Scopus - 48Web of Science - 52
Co-authors Inyoung Kim
2012 Lee JM, Kim IY, Han SY, Kim TW, Hwang SJ, 'Graphene nanosheets as a platform for the 2D ordering of metal oxide nanoparticles: Mesoporous 2D aggregate of anatase TiO

Graphene nanosheets are successfully applied as an effective platform for the 2D ordering of metal oxide nanoparticles. Mesoporous 2D aggregates of anatase TiO 2 nanoparticles are... [more]

Graphene nanosheets are successfully applied as an effective platform for the 2D ordering of metal oxide nanoparticles. Mesoporous 2D aggregates of anatase TiO 2 nanoparticles are synthesized by the heat treatment of the uniformly hybridized nanocomposite of layered titanate-reduced graphene oxide (RGO) at elevated temperatures. The precursor layered titanate-RGO nanocomposite is prepared by self-assembly of anionic RGO nanosheets and cationic TiO 2 nanosols. The calcination of the as-prepared layered titanate-RGO nanocomposite at 500 °C induces a structural and morphological change of layered titanate nanoplates into anatase TiO 2 nanoparticles without significant modification of the RGO nanosheet. Increasing the heating temperature to 600 °C gives rise to elimination of the RGO component, leading to the formation of sheetlike porous aggregates of RGO-free TiO 2 nanoparticles. The nanocomposites calcined at 500-700 °C display promising functionality as negative electrodes for lithium ion batteries. Among the present calcined derivatives, the 2D sheet-shaped aggregate of TiO 2 nanoparticles obtained from calcination at 600 °C delivers the greatest specific discharge capacity with good capacity retention for all current density conditions applied. Such superior electrode performance of the nanocomposite calcined at 600 °C is attributable both to the improved stability of the crystal structure and crystal morphology of titania and to the enhancement of Li + ion transport through the enlargement of mesopores. The present findings clearly demonstrate the usefulness of RGO nanosheets as a platform for 2D-ordered superstructures of metal oxide nanoparticles with improved electrode performance. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DOI 10.1002/chem.201200551
Citations Scopus - 29Web of Science - 31
Co-authors Inyoung Kim
2012 Kim IY, Lee JM, Kim TW, Kim HN, Kim HI, Choi W, Hwang SJ, 'A strong electronic coupling between graphene nanosheets and layered titanate nanoplates: A soft-chemical route to highly porous nanocomposites with improved photocatalytic activity', Small, 8 1038-1048 (2012)

Strongly coupled nanocomposites of layered titanate and reduced graphene oxide (RGO) are synthesized by electrostatically derived self-assembly between negatively charged RGO nano... [more]

Strongly coupled nanocomposites of layered titanate and reduced graphene oxide (RGO) are synthesized by electrostatically derived self-assembly between negatively charged RGO nanosheets and positively charged TiO 2 nanosols, which is then followed by a phase transition of the anatase TiO 2 component into layered titanate. The resulting nanocomposite consists of thin 2D nanoplates of lepidocrocite-type layered titanate immobilized on the surface of RGO nanosheets. The composite formation with RGO nanosheets is effective not only in promoting the phase transition of anatase TiO 2 nanosols, but also in improving the thermal stability of the layered titanate, indicating the role of RGO nanosheets as an agent for directing and stabilizing layered structures. The layered-titanate-RGO nanocomposites exhibit remarkably expanded surface area with the formation of micropores and mesopores. The composite formation with RGO nanosheets gives rise to the disappearance of the reflectance edge of layered titanate in the diffuse reflectance UV-vis spectra, indicating a strong electronic coupling between the RGO and layered titanate. The strong electronic correlation between the two components is further evidenced by the visible-light-induced generation of photocurrents after the hybridization with RGO. The layered-titanate-RGO nanocomposite shows a higher activity for the photodegradation of organic molecules than uncomposited layered titanate, underscoring the usefulness of graphene hybridization in improving the photocatalyst performance of layered titanate. The experimental findings presented here clearly demonstrate that the self-assembly of metal oxide nanoparticles with RGO 2D nanosheets is quite effective not only in synthesizing porous metal-oxide-graphene nanocomposites with improved photo-induced functionality, but also in achieving strong electronic coupling between RGO and metal oxides. Strongly coupled nanocomposites of layered titanate and reduced graphene oxide (RGO) are synthesized by self-assembly involving RGO nanosheets and TiO 2 nanosols and the following phase transformation of titania. A strong electronic coupling between the two nanospecies remarkably enhances visible light absorption. The hybridization with RGO improves the photocatalytic activity of the layered titanate for the visible-induced generation of photocurrent and the photodegradation of organic molecules. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DOI 10.1002/smll.201101703
Citations Scopus - 96Web of Science - 97
Co-authors Inyoung Kim
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Research Supervision

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Current Supervision

Commenced Level of Study Research Title Program Supervisor Type
2019 PhD Ferromagnetism in 2D Materials PhD (Chemical Engineering), Faculty of Engineering and Built Environment, The University of Newcastle Co-Supervisor
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Dr Jangmee Lee

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Research Associate
School of Engineering
Faculty of Engineering and Built Environment

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Email jangmee.lee@newcastle.edu.au
Phone (02) 4921 5278
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