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Xu X, Aggarwal D, Shankar K. Instantaneous Property Prediction and Inverse Design of Plasmonic Nanostructures Using Machine Learning: Current Applications and Future Directions. NANOMATERIALS 2022; 12:nano12040633. [PMID: 35214962 PMCID: PMC8874423 DOI: 10.3390/nano12040633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 02/06/2022] [Accepted: 02/08/2022] [Indexed: 02/06/2023]
Abstract
Advances in plasmonic materials and devices have given rise to a variety of applications in photocatalysis, microscopy, nanophotonics, and metastructures. With the advent of computing power and artificial neural networks, the characterization and design process of plasmonic nanostructures can be significantly accelerated using machine learning as opposed to conventional FDTD simulations. The machine learning (ML) based methods can not only perform with high accuracy and return optical spectra and optimal design parameters, but also maintain a stable high computing efficiency without being affected by the structural complexity. This work reviews the prominent ML methods involved in forward simulation and inverse design of plasmonic nanomaterials, such as Convolutional Neural Networks, Generative Adversarial Networks, Genetic Algorithms and Encoder–Decoder Networks. Moreover, we acknowledge the current limitations of ML methods in the context of plasmonics and provide perspectives on future research directions.
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Vahidzadeh E, Zeng S, Alam KM, Kumar P, Riddell S, Chaulagain N, Gusarov S, Kobryn AE, Shankar K. Harvesting Hot Holes in Plasmon-Coupled Ultrathin Photoanodes for High-Performance Photoelectrochemical Water Splitting. ACS APPLIED MATERIALS & INTERFACES 2021; 13:42741-42752. [PMID: 34476945 DOI: 10.1021/acsami.1c10698] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The harvesting of hot carriers produced by plasmon decay to generate electricity or drive a chemical reaction enables the reduction of the thermalization losses associated with supra-band gap photons in semiconductor photoelectrochemical (PEC) cells. Through the broadband harvesting of light, hot-carrier PEC devices also produce a sensitizing effect in heterojunctions with wide-band gap metal oxide semiconductors possessing good photostability and catalytic activity but poor absorption of visible wavelength photons. There are several reports of hot electrons in Au injected over the Schottky barrier into crystalline TiO2 and subsequently utilized to drive a chemical reaction but very few reports of hot hole harvesting. In this work, we demonstrate the efficient harvesting of hot holes in Au nanoparticles (Au NPs) covered with a thin layer of amorphous TiO2 (a-TiO2). Under AM1.5G 1 sun illumination, photoanodes consisting of a single layer of ∼50 nm diameter Au NPs coated with a 10 nm shell of a-TiO2 (Au@a-TiO2) generated 2.5 mA cm-2 of photocurrent in 1 M KOH under 0.6 V external bias, rising to 3.7 mA cm-2 in the presence of a hole scavenger (methanol). The quantum yield for hot-carrier-mediated photocurrent generation was estimated to be close to unity for high-energy photons (λ < 420 nm). Au@a-TiO2 photoelectrodes produced a small positive photocurrent of 0.1 mA cm-2 even at a bias of -0.6 V indicating extraction of hot holes even at a strong negative bias. These results together with density functional theory modeling and scanning Kelvin probe force microscope data indicate fast injection of hot holes from Au NPs into a-TiO2 and light harvesting performed near-exclusively by Au NPs. For comparison, Au NPs coated with a 10 nm shell of Al2O3 (Au@Al2O3) generated 0.02 mA cm-2 of photocurrent in 1 M KOH under 0.6 V external bias. These results underscore the critical role played by a-TiO2 in the extraction of holes in Au@a-TiO2 photoanodes, which is not replicated by an ordinary dielectric shell. It is also demonstrated here that an ultrathin photoanode (<100 nm in maximum thickness) can efficiently drive sunlight-driven water splitting.
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Affiliation(s)
- Ehsan Vahidzadeh
- Department of Electrical and Computer Engineering, University of Alberta, 9211-116 Street, Edmonton, Alberta T6G 1H9, Canada
| | - Sheng Zeng
- Department of Electrical and Computer Engineering, University of Alberta, 9211-116 Street, Edmonton, Alberta T6G 1H9, Canada
| | - Kazi M Alam
- Department of Electrical and Computer Engineering, University of Alberta, 9211-116 Street, Edmonton, Alberta T6G 1H9, Canada
- Nanotechnology Research Centre, National Research Council Canada, 11421 Saskatchewan Drive, Edmonton, Alberta T6G 2M9, Canada
| | - Pawan Kumar
- Department of Electrical and Computer Engineering, University of Alberta, 9211-116 Street, Edmonton, Alberta T6G 1H9, Canada
| | - Saralyn Riddell
- Department of Electrical and Computer Engineering, University of Alberta, 9211-116 Street, Edmonton, Alberta T6G 1H9, Canada
| | - Narendra Chaulagain
- Department of Electrical and Computer Engineering, University of Alberta, 9211-116 Street, Edmonton, Alberta T6G 1H9, Canada
| | - Sergey Gusarov
- Nanotechnology Research Centre, National Research Council Canada, 11421 Saskatchewan Drive, Edmonton, Alberta T6G 2M9, Canada
| | - Alexander E Kobryn
- Nanotechnology Research Centre, National Research Council Canada, 11421 Saskatchewan Drive, Edmonton, Alberta T6G 2M9, Canada
| | - Karthik Shankar
- Department of Electrical and Computer Engineering, University of Alberta, 9211-116 Street, Edmonton, Alberta T6G 1H9, Canada
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Manuel AP, Shankar K. Hot Electrons in TiO 2-Noble Metal Nano-Heterojunctions: Fundamental Science and Applications in Photocatalysis. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:1249. [PMID: 34068571 PMCID: PMC8151081 DOI: 10.3390/nano11051249] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 05/03/2021] [Accepted: 05/05/2021] [Indexed: 01/06/2023]
Abstract
Plasmonic photocatalysis enables innovation by harnessing photonic energy across a broad swathe of the solar spectrum to drive chemical reactions. This review provides a comprehensive summary of the latest developments and issues for advanced research in plasmonic hot electron driven photocatalytic technologies focusing on TiO2-noble metal nanoparticle heterojunctions. In-depth discussions on fundamental hot electron phenomena in plasmonic photocatalysis is the focal point of this review. We summarize hot electron dynamics, elaborate on techniques to probe and measure said phenomena, and provide perspective on potential applications-photocatalytic degradation of organic pollutants, CO2 photoreduction, and photoelectrochemical water splitting-that benefit from this technology. A contentious and hitherto unexplained phenomenon is the wavelength dependence of plasmonic photocatalysis. Many published reports on noble metal-metal oxide nanostructures show action spectra where quantum yields closely follow the absorption corresponding to higher energy interband transitions, while an equal number also show quantum efficiencies that follow the optical response corresponding to the localized surface plasmon resonance (LSPR). We have provided a working hypothesis for the first time to reconcile these contradictory results and explain why photocatalytic action in certain plasmonic systems is mediated by interband transitions and in others by hot electrons produced by the decay of particle plasmons.
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Affiliation(s)
- Ajay P. Manuel
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada;
| | - Karthik Shankar
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada;
- Future Energy Systems Research Institute, University of Alberta, Edmonton, AB T6G 1K4, Canada
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Vahidzadeh E, Shankar K. Artificial Neural Network-Based Prediction of the Optical Properties of Spherical Core-Shell Plasmonic Metastructures. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:633. [PMID: 33806266 PMCID: PMC8001937 DOI: 10.3390/nano11030633] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 02/24/2021] [Accepted: 02/26/2021] [Indexed: 12/24/2022]
Abstract
The substitution of time- and labor-intensive empirical research as well as slow finite difference time domain (FDTD) simulations with revolutionary techniques such as artificial neural network (ANN)-based predictive modeling is the next trend in the field of nanophotonics. In this work, we demonstrated that neural networks with proper architectures can rapidly predict the far-field optical response of core-shell plasmonic metastructures. The results obtained with artificial neural networks are comparable with FDTD simulations in accuracy but the speed of obtaining them is between 100-1000 times faster than FDTD simulations. Further, we have proven that ANNs does not have problems associated with FDTD simulations such as dependency of the speed of convergence on the size of the structure. The other trend in photonics is the inverse design problem, where the far-field optical response of a spherical core-shell metastructure can be linked to the design parameters such as type of the material(s), core radius, and shell thickness using a neural network. The findings of this paper provide evidence that machine learning (ML) techniques such as artificial neural networks can potentially replace time-consuming finite domain methods in the future.
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Affiliation(s)
| | - Karthik Shankar
- Department of Electrical and Computer Engineering, University of Alberta, 9211-116 St, Edmonton, AB T6G 1H9, Canada;
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Manuel AP, Barya P, Riddell S, Zeng S, Alam KM, Shankar K. Plasmonic photocatalysis and SERS sensing using ellipsometrically modeled Ag nanoisland substrates. NANOTECHNOLOGY 2020; 31:365301. [PMID: 32191930 DOI: 10.1088/1361-6528/ab814c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Silver nanoislands are key platforms for plasmonic photocatalysis, SERS sensing and optical metamaterials due to their localized surface plasmon resonances. The low intrinsic loss in Ag enables high local electromagnetic field enhancements. Solution-based fabrication techniques, while cheap, result in highly non-reproducible plasmonic substrates with wide sample-to-sample variability in geometry, optical resonances and Q-factors. Herein, we present a non-lithographic method of forming silver nanoislands based on sputter deposition of Ag films followed by elevated temperature annealing to induce spontaneous dewetting. The resulting plasmonic substrates show reproducible, well-defined LSPR resonances with high ensemble Q-factors whose optical properties could be modeled using spectroscopic ellipsometry to yield n and k values across the visible range. UV-Vis-NIR, and XRD analyses define the optical and crystallographic characteristics of the Ag nanoisland samples. FESEM was utilized to discern the geometry and architecture of the Ag nanoisland as well as their uniformity and monodispersity. Our vacuum deposited Ag nanoislands demonstrated excellent photocatalytic activity for the transformation of 4-nitrobenzenethiol (4-NBT) and 4-aminothiophenol (PATP) into p,p'-dimercaptoazobenzene (DMAB).
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Affiliation(s)
- Ajay P Manuel
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton T6G 1H9, Canada
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Gao Y, Nie W, Zhu Q, Wang X, Wang S, Fan F, Li C. The Polarization Effect in Surface‐Plasmon‐Induced Photocatalysis on Au/TiO
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Nanoparticles. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202007706] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Yuying Gao
- State Key Laboratory of Catalysis Dalian National Laboratory for Clean Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Wei Nie
- State Key Laboratory of Catalysis Dalian National Laboratory for Clean Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Qianhong Zhu
- State Key Laboratory of Catalysis Dalian National Laboratory for Clean Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Xun Wang
- State Key Laboratory of Catalysis Dalian National Laboratory for Clean Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China
| | - Shengyang Wang
- State Key Laboratory of Catalysis Dalian National Laboratory for Clean Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China
| | - Fengtao Fan
- State Key Laboratory of Catalysis Dalian National Laboratory for Clean Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China
| | - Can Li
- State Key Laboratory of Catalysis Dalian National Laboratory for Clean Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China
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Gao Y, Nie W, Zhu Q, Wang X, Wang S, Fan F, Li C. The Polarization Effect in Surface‐Plasmon‐Induced Photocatalysis on Au/TiO
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Nanoparticles. Angew Chem Int Ed Engl 2020; 59:18218-18223. [DOI: 10.1002/anie.202007706] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/11/2020] [Indexed: 11/10/2022]
Affiliation(s)
- Yuying Gao
- State Key Laboratory of Catalysis Dalian National Laboratory for Clean Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Wei Nie
- State Key Laboratory of Catalysis Dalian National Laboratory for Clean Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Qianhong Zhu
- State Key Laboratory of Catalysis Dalian National Laboratory for Clean Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Xun Wang
- State Key Laboratory of Catalysis Dalian National Laboratory for Clean Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China
| | - Shengyang Wang
- State Key Laboratory of Catalysis Dalian National Laboratory for Clean Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China
| | - Fengtao Fan
- State Key Laboratory of Catalysis Dalian National Laboratory for Clean Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China
| | - Can Li
- State Key Laboratory of Catalysis Dalian National Laboratory for Clean Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China
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Schneid AC, Quevedo AB, Pereira MB, Araújo PF, Franco N, Machado G, Moro CC, de Menezes EW, Costa TMH, Benvenutti EV. New strategy to obtain high surface area anatase nanotube/AuNP photocatalyst. NANOTECHNOLOGY 2019; 30:065604. [PMID: 30523846 DOI: 10.1088/1361-6528/aaf17e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Anatase nanotubes with high surface area (ca. 350 m2 g-1), containing gold nanoparticles, were successfully obtained from trititanate nanotubes, prepared by a template-free hydrothermal method, and calcined at 450 °C. The high surface area and tubular morphology were attained due to the presence of ionic silsesquioxane, which acts as anti-sintering agent for titania during calcination process, by forming a thin silica coating between anatase nanotubes. Additionally, the ionic silsesquioxane also acts as stabilizing and adhesion agent for gold nanoparticles on the surface of anatase nanotubes. The influence of the ionic silsesquioxane on the morphological and textural properties of anatase nanotubes was studied in three different moments during the synthesis: before, after and before/after nanotubes were rolled up. The photocatalytic activity of the nanotube samples was evaluated by hydrogen generation showing remarkable enhancement in hydrogen production and stability of catalyst when compare with the bare anatase sample and commercial P-25.
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Affiliation(s)
- Andressa C Schneid
- LSS, Laboratory of Solids and Surfaces, Instituto de Química, UFRGS, CEP 91501-970, Porto Alegre, RS, Brazil
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Koneti S, Borges J, Roiban L, Rodrigues MS, Martin N, Epicier T, Vaz F, Steyer P. Electron Tomography of Plasmonic Au Nanoparticles Dispersed in a TiO 2 Dielectric Matrix. ACS APPLIED MATERIALS & INTERFACES 2018; 10:42882-42890. [PMID: 30457319 DOI: 10.1021/acsami.8b16436] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Plasmonic Au nanoparticles (AuNPs) embedded into a TiO2 dielectric matrix were analyzed by combining two-dimensional and three-dimensional electron microscopy techniques. The preparation method was reactive magnetron sputtering, followed by thermal annealing treatments at 400 and 600 °C. The goal was to assess the nanostructural characteristics and correlate them with the optical properties of the AuNPs, particularly the localized surface plasmon resonance (LSPR) behavior. High-angle annular dark field-scanning transmission electron microscopy results showed the presence of small-sized AuNPs (quantum size regime) in the as-deposited Au-TiO2 film, resulting in a negligible LSPR response. The in-vacuum thermal annealing at 400 °C induced the formation of intermediate-sized nanoparticles (NPs), in the range of 10-40 nm, which led to the appearance of a well-defined LSPR band, positioned at 636 nm. Electron tomography revealed that most of the NPs are small-sized and are embedded into the TiO2 matrix, whereas the larger NPs are located at the surface. Annealing at 600 °C promotes a bimodal size distribution with intermediate-sized NPs embedded in the matrix and big-sized NPs, up to 100 nm, appearing at the surface. The latter are responsible for a broadening and a redshift, to 645 nm, in the LSPR band because of increase of scattering-to-absorption ratio. Beyond differentiating and quantifying the surface and embedded NPs, electron tomography also provided the identification of "hot-spots". The presence of NPs at the surface, individual or in dimers, permits adsorption sites for LSPR sensing and for surface-enhanced spectroscopies, such as surface-enhanced Raman scattering.
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Affiliation(s)
- Siddardha Koneti
- Université Lyon, INSA-Lyon, MATEIS UMR CNRS 5510 , 21 Avenue Jean Capelle , 69621 Villeurbanne Cedex , France
| | - Joel Borges
- Centro de Física , Universidade do Minho , Campus de Gualtar , 4710 057 Braga , Portugal
| | - Lucian Roiban
- Université Lyon, INSA-Lyon, MATEIS UMR CNRS 5510 , 21 Avenue Jean Capelle , 69621 Villeurbanne Cedex , France
| | - Marco S Rodrigues
- Centro de Física , Universidade do Minho , Campus de Gualtar , 4710 057 Braga , Portugal
| | - Nicolas Martin
- Institut FEMTO-ST, UMR 6174 CNRS, Université Bourgogne Franche-Comté , 15B, Avenue des Montboucons , 25030 Besançon Cedex , France
| | - Thierry Epicier
- Université Lyon, INSA-Lyon, MATEIS UMR CNRS 5510 , 21 Avenue Jean Capelle , 69621 Villeurbanne Cedex , France
| | - Filipe Vaz
- Centro de Física , Universidade do Minho , Campus de Gualtar , 4710 057 Braga , Portugal
| | - Philippe Steyer
- Université Lyon, INSA-Lyon, MATEIS UMR CNRS 5510 , 21 Avenue Jean Capelle , 69621 Villeurbanne Cedex , France
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Xie JF, Li HT, Gao Q, Wang H, Gong YS. A convenient and efficient precursor transformation route to well-dispersed, stable, and highly accessible supported Au nanocatalysts with excellent catalytic hydrogenation performances. RSC Adv 2018; 8:39384-39393. [PMID: 35558033 PMCID: PMC9090991 DOI: 10.1039/c8ra08379g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 11/19/2018] [Indexed: 12/28/2022] Open
Abstract
A new, convenient, and efficient precursor transformation route for the synthesis of supported Au nanocatalysts was reported. In this strategy, [Au(en)2]3+-riched titanate nanospheres (en: ethylenediamine) with hierarchical flower-like architecture were pre-synthesized via “ammonia etching-ion exchange” processes and then used as the precursors of the objective catalysts. Direct pyrolysis of these precursors, varying in amount of [Au(en)2]3+, led to the formation of Au nanoparticles (AuNPs) with different contents uniformly supported on highly crystalline titania nanoflowers (fTiO2). The fTiO2-supported AuNPs nanocomposites possessed highly open porous structures with large surface areas (142.3–149.3 m2 g−1), which could allow guest molecules to diffuse in and out easily. More interestingly, the formed AuNPs with small size (∼3.8 nm) were well-dispersed and partially embedded into the nanosheets of fTiO2, which was beneficial for achieving high activity while avoiding their detachment from the support during application. Accordingly, the AuNPs/TiO2 catalysts exhibited superior catalytic properties for 4-nitrophenol hydrogenation with significantly higher catalytic efficiencies than many previously reported heterogeneous catalysts. Moreover, the catalytic activity could remain almost unchanged after being recycled several times, demonstrating their high stability. These findings open up a new possibility for rational design and synthesis of supported catalysts for diverse catalytic applications. Synthesis of well-dispersed, stable, and highly accessible supported Au nanocatalysts was achieved via a new and efficient precursor transformation route.![]()
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Affiliation(s)
- Jin-Feng Xie
- Department of Chemistry
- Faculty of Material Science and Chemistry
- China University of Geosciences
- Wuhan 430074
- PR China
| | - Hai-Tao Li
- Department of Chemistry
- Faculty of Material Science and Chemistry
- China University of Geosciences
- Wuhan 430074
- PR China
| | - Qiang Gao
- Department of Chemistry
- Faculty of Material Science and Chemistry
- China University of Geosciences
- Wuhan 430074
- PR China
| | - Hao Wang
- Department of Chemistry
- Faculty of Material Science and Chemistry
- China University of Geosciences
- Wuhan 430074
- PR China
| | - Yan-Sheng Gong
- Department of Materials Science and Engineering
- Faculty of Material Science and Chemistry
- China University of Geosciences
- Wuhan 430074
- PR China
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