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Xiao Y, Fu J, Pihosh Y, Karmakar K, Zhang B, Domen K, Li Y. Interface engineering for photoelectrochemical oxygen evolution reaction. Chem Soc Rev 2025; 54:1268-1317. [PMID: 39679444 DOI: 10.1039/d4cs00309h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2024]
Abstract
Photoelectrochemical (PEC) water splitting provides a promising approach for solving sustainable energy challenges and achieving carbon neutrality goals. The oxygen evolution reaction (OER), a key bottleneck in the PEC water-splitting system occurring at the photoanode/electrolyte interface, plays a fundamental role in sustainable solar fuel production. Proper surface or interface engineering strategies have been proven to be necessary to achieve efficient and stable PEC water oxidation. This review summarizes the recent advances in interface engineering, including junction formation, surface doping, surface passivation or protection, surface sensitization, and OER cocatalyst modification, while highlighting the remarkable research achievements in the field of PEC water splitting. The benefits of each interface engineering strategy and how it enhances the device performance are critically analyzed and compared. Finally, the outlook for the development of interface engineering for efficient PEC water splitting is briefly discussed. This review illustrates the importance of employing rational interface engineering in realizing efficient and stable PEC water splitting devices.
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Affiliation(s)
- Yequan Xiao
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 611731, China.
- Hubei Provincial Engineering Research Center for Solar Energy High-value Utilization and Green Conversion, China Three Gorges University, Yichang, Hubei 443002, China
| | - Jie Fu
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 611731, China.
| | - Yuriy Pihosh
- Office of University Professors, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Keshab Karmakar
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 611731, China.
| | - Beibei Zhang
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 611731, China.
| | - Kazunari Domen
- Office of University Professors, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-8656, Japan
- Research Initiative for Supra-Materials, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, 4-17-1 Wakasato, Nagano-shi, Nagano 380-8553, Japan
| | - Yanbo Li
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 611731, China.
- Key Laboratory of Quantum Physics and Photonic Quantum Information, Ministry of Education, University of Electronic Science and Technology of China, Chengdu 611731, China
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Choi MJ, Kim TL, Choi KS, Sohn W, Lee TH, Lee SA, Park H, Jeong SY, Yang JW, Lee S, Jang HW. Controlled Band Offsets in Ultrathin Hematite for Enhancing the Photoelectrochemical Water Splitting Performance of Heterostructured Photoanodes. ACS APPLIED MATERIALS & INTERFACES 2022; 14:7788-7795. [PMID: 35040620 DOI: 10.1021/acsami.1c18886] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Formation of type II heterojunctions is a promising strategy to enhance the photoelectrochemical performance of water-splitting photoanodes, which has been tremendously studied. However, there have been few studies focusing on the formation of type II heterojunctions depending on the thickness of the overlayer. Here, enhanced photoelectrochemical activities of a Fe2O3 film deposited-BiVO4/WO3 heterostructure with different thicknesses of the Fe2O3 layer have been investigated. The Fe2O3 (10 nm)/BiVO4/WO3 heterojunction photoanode shows a much higher photocurrent density compared to the Fe2O3 (100 nm)/BiVO4/WO3 photoanode. The Fe2O3 (10 nm)/BiVO4/WO3 trilayer heterojunction anodes have sequential type II junctions, while a thick Fe2O3 overlayer forms an inverse type II junction between Fe2O3 and BiVO4. Furthermore, the incident-photon-to-current efficiency measured under back-illumination is higher than those measured under front-illumination, demonstrating the importance of the illumination sequence for light absorption and charge transfer and transport. This study shows that the thickness of the oxide overlayer influences the energy band alignment and can be a strategy to improve solar water splitting performance. Based on our findings, we propose a photoanode design strategy for efficient photoelectrochemical water splitting.
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Affiliation(s)
- Min-Ju Choi
- Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Gwanak-ro 1, Seoul 08826, Republic of Korea
| | - Taemin L Kim
- Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Gwanak-ro 1, Seoul 08826, Republic of Korea
| | - Kyoung Soon Choi
- Advanced Nano Surface Research Group, Korea Basic Science Institute, Daejeon 34133, Republic of Korea
| | - Woonbae Sohn
- Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Gwanak-ro 1, Seoul 08826, Republic of Korea
| | - Tae Hyung Lee
- Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Gwanak-ro 1, Seoul 08826, Republic of Korea
| | - Sol A Lee
- Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Gwanak-ro 1, Seoul 08826, Republic of Korea
| | - Hoonkee Park
- Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Gwanak-ro 1, Seoul 08826, Republic of Korea
| | - Sang Yun Jeong
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
| | - Jin Wook Yang
- Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Gwanak-ro 1, Seoul 08826, Republic of Korea
| | - Sanghan Lee
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
| | - Ho Won Jang
- Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Gwanak-ro 1, Seoul 08826, Republic of Korea
- Advanced Institute of Convergence Technology, Seoul National University, Suwon 16229, Republic of Korea
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Xie L, Chen Y, Zhao Y, Zhou G, Nötzel R. InN/InGaN Quantum Dot Abiotic One-Compartment Glucose Photofuel Cell: Power Supply and Sensing. ACS OMEGA 2022; 7:1437-1443. [PMID: 35036805 PMCID: PMC8756593 DOI: 10.1021/acsomega.1c06138] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 12/17/2021] [Indexed: 06/14/2023]
Abstract
InN/InGaN quantum dots (QDs) are introduced as an efficient photoanode for a novel abiotic one-compartment photofuel cell (PFC) with a Pt cathode and glucose as a biofuel. Due to the high catalytic activity and selectivity of the InN/InGaN QDs toward oxidation reactions, the PFC operates without a membrane under physiologically mild conditions at medium to low glucose concentrations with a noble-metal-free photoanode. A relatively high short-circuit photocurrent density of 0.56 mA/cm2 and a peak output power density of 0.22 mW/cm2 are achieved under 1 sun illumination for a 0.1 M glucose concentration with optimized InN/InGaN QDs of the right size. The super-linear dependence of the short-circuit photocurrent density and the output power density as a function of the logarithmic glucose concentration makes the PFC well suited for sensing, covering the 4-6 mM range of glucose concentration in blood under normal conditions with good selectivity. No degradation of the PFC operation over time is observed.
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Affiliation(s)
- Lingyun Xie
- Guangdong
Provincial Key Laboratory of Optical Information Materials and Technology,
South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, People’s Republic of China
| | - Yongjie Chen
- Guangdong
Provincial Key Laboratory of Optical Information Materials and Technology,
South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, People’s Republic of China
| | - Yingzhi Zhao
- Guangdong
Provincial Key Laboratory of Optical Information Materials and Technology,
South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, People’s Republic of China
| | - Guofu Zhou
- Guangdong
Provincial Key Laboratory of Optical Information Materials and Technology,
South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, People’s Republic of China
- National
Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou 510006, People’s Republic of China
| | - Richard Nötzel
- Guangdong
Provincial Key Laboratory of Optical Information Materials and Technology,
South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, People’s Republic of China
- National
Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou 510006, People’s Republic of China
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Xing Z, Zhang X, Yang W, Li H, Zhao Y, Wei T, Bian L, Chen G, Qin H, Lu S. Improved photocatalytic activity and stability of InGaN quantum dots/C 3N 4heterojunction photoelectrode for CO 2reduction and hydrogen production. NANOTECHNOLOGY 2021; 32:505705. [PMID: 34492642 DOI: 10.1088/1361-6528/ac2450] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 09/07/2021] [Indexed: 06/13/2023]
Abstract
Photocatalytic conversion of CO2to produce fuel is considered a promising approach to reduce CO2emissions and tackle energy crisis. GaN-based materials have been studied for CO2reduction because of their excellent optical properties and band structure. However, low photocatalytic activity and severe photocorrosion of GaN-based photoelectrode greatly limit their applications. In this work, photocatalytic activity was improved by adopting InGaN quantum dots (QDs) combined with C3N4nano-sheets as photoanode, and thus the efficiency of CO2reduction and the selectivity of hydrogen production were increased significantly. In addition, the photoelectron-chemical corrosion of photoelectrodes has been apparently controlled. InGaN QDs/C3N4has the highest CO and H2productions rates of 14.69μmol mol-1h-1and 140μmol mol-1h-1which were 2.2 times and 14.5 times than that of InGaN film photoelectrode, respectively. The enhancement of photocatalytic activity is attributed to C3N4modification and a large electric dipole forming on the surface of InGaN QDs, which facilitate the separation and transfer of photo-generated carriers and thus promote CO2reduction reaction. This work provides a promising strategy for the development of GaN-based photoanodes with superior stability and efficiency.
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Affiliation(s)
- Zhiwei Xing
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
- Key Lab of Nanodevices and Applications, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences (CAS), Suzhou, Jiangsu 215123, People's Republic of China
| | - Xue Zhang
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
- Key Lab of Nanodevices and Applications, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences (CAS), Suzhou, Jiangsu 215123, People's Republic of China
| | - Wenxian Yang
- Key Lab of Nanodevices and Applications, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences (CAS), Suzhou, Jiangsu 215123, People's Republic of China
| | - Huan Li
- School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300132, People's Republic of China
| | - Yukun Zhao
- Key Lab of Nanodevices and Applications, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences (CAS), Suzhou, Jiangsu 215123, People's Republic of China
| | - Tieshi Wei
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
- Key Lab of Nanodevices and Applications, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences (CAS), Suzhou, Jiangsu 215123, People's Republic of China
| | - Lifeng Bian
- Key Lab of Nanodevices and Applications, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences (CAS), Suzhou, Jiangsu 215123, People's Republic of China
| | - Guifeng Chen
- School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300132, People's Republic of China
| | - Hua Qin
- Key Lab of Nanodevices and Applications, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences (CAS), Suzhou, Jiangsu 215123, People's Republic of China
| | - Shulong Lu
- Key Lab of Nanodevices and Applications, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences (CAS), Suzhou, Jiangsu 215123, People's Republic of China
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Scalable, highly stable Si-based metal-insulator-semiconductor photoanodes for water oxidation fabricated using thin-film reactions and electrodeposition. Nat Commun 2021; 12:3982. [PMID: 34172754 PMCID: PMC8233328 DOI: 10.1038/s41467-021-24229-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 06/07/2021] [Indexed: 12/02/2022] Open
Abstract
Metal-insulator-semiconductor (MIS) structures are widely used in Si-based solar water-splitting photoelectrodes to protect the Si layer from corrosion. Typically, there is a tradeoff between efficiency and stability when optimizing insulator thickness. Moreover, lithographic patterning is often required for fabricating MIS photoelectrodes. In this study, we demonstrate improved Si-based MIS photoanodes with thick insulating layers fabricated using thin-film reactions to create localized conduction paths through the insulator and electrodeposition to form metal catalyst islands. These fabrication approaches are low-cost and highly scalable, and yield MIS photoanodes with low onset potential, high saturation current density, and excellent stability. By combining this approach with a p+n-Si buried junction, further improved oxygen evolution reaction (OER) performance is achieved with an onset potential of 0.7 V versus reversible hydrogen electrode (RHE) and saturation current density of 32 mA/cm2 under simulated AM1.5G illumination. Moreover, in stability testing in 1 M KOH aqueous solution, a constant photocurrent density of ~22 mA/cm2 is maintained at 1.3 V versus RHE for 7 days. Authors demonstrate Si-based MIS photoanodes using Al thin-film reactions to create localized conduction paths through the insulator and Ni electrodeposition to form metal catalyst islands. These approaches yielded low onset potential, high saturation current density, and excellent stability.
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Eidsvåg H, Bentouba S, Vajeeston P, Yohi S, Velauthapillai D. TiO 2 as a Photocatalyst for Water Splitting-An Experimental and Theoretical Review. Molecules 2021; 26:molecules26061687. [PMID: 33802911 PMCID: PMC8002707 DOI: 10.3390/molecules26061687] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 03/09/2021] [Accepted: 03/10/2021] [Indexed: 11/16/2022] Open
Abstract
Hydrogen produced from water using photocatalysts driven by sunlight is a sustainable way to overcome the intermittency issues of solar power and provide a green alternative to fossil fuels. TiO2 has been used as a photocatalyst since the 1970s due to its low cost, earth abundance, and stability. There has been a wide range of research activities in order to enhance the use of TiO2 as a photocatalyst using dopants, modifying the surface, or depositing noble metals. However, the issues such as wide bandgap, high electron-hole recombination time, and a large overpotential for the hydrogen evolution reaction (HER) persist as a challenge. Here, we review state-of-the-art experimental and theoretical research on TiO2 based photocatalysts and identify challenges that have to be focused on to drive the field further. We conclude with a discussion of four challenges for TiO2 photocatalysts-non-standardized presentation of results, bandgap in the ultraviolet (UV) region, lack of collaboration between experimental and theoretical work, and lack of large/small scale production facilities. We also highlight the importance of combining computational modeling with experimental work to make further advances in this exciting field.
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Affiliation(s)
- Håkon Eidsvåg
- Department of Computing, Mathematics and Physics, Western Norway University of Applied Sciences, Inndalsveien 28, Box 5063, N-5009 Bergen, Norway;
- Correspondence: (H.E.); (D.V.); Tel.: +47-980-61-444 (H.E.); +47-55-58-77-11 (D.V.)
| | - Said Bentouba
- Department of Computing, Mathematics and Physics, Western Norway University of Applied Sciences, Inndalsveien 28, Box 5063, N-5009 Bergen, Norway;
| | - Ponniah Vajeeston
- Center for Materials Science and Nanotechnology, Department of Chemistry, University of Oslo, Box 1033 Blindern, N-0315 Oslo, Norway;
| | - Shivatharsiny Yohi
- Department of Chemistry, Faculty of Science, University of Jaffna, Sir. Pon, Ramanathan Rd, Jaffna 40000, Sri Lanka;
| | - Dhayalan Velauthapillai
- Department of Computing, Mathematics and Physics, Western Norway University of Applied Sciences, Inndalsveien 28, Box 5063, N-5009 Bergen, Norway;
- Correspondence: (H.E.); (D.V.); Tel.: +47-980-61-444 (H.E.); +47-55-58-77-11 (D.V.)
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Varun BV, Vaithegi K, Yi S, Park SB. Nature-inspired remodeling of (aza)indoles to meta-aminoaryl nicotinates for late-stage conjugation of vitamin B 3 to (hetero)arylamines. Nat Commun 2020; 11:6308. [PMID: 33298909 PMCID: PMC7726565 DOI: 10.1038/s41467-020-19610-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 10/14/2020] [Indexed: 12/16/2022] Open
Abstract
Despite the availability of numerous routes to substituted nicotinates based on the Bohlmann–Rahtz pyridine synthesis, the existing methods have several limitations, such as the inevitable ortho-substitutions and the inability to conjugate vitamin B3 to other pharmaceutical agents. Inspired by the biosynthesis of nicotinic acid (a form of vitamin B3) from tryptophan, we herein report the development of a strategy for the synthesis of meta-aminoaryl nicotinates from 3-formyl(aza)indoles. Our strategy is mechanistically different from the reported routes and involves the transformation of (aza)indole scaffolds into substituted meta-aminobiaryl scaffolds via Aldol-type addition and intramolecular cyclization followed by C–N bond cleavage and re-aromatization. Unlike previous synthetic routes, this biomimetic method utilizes propiolates as enamine precursors and thus allows access to ortho-unsubstituted nicotinates. In addition, the synthetic feasibility toward the halo-/boronic ester-substituted aminobiaryls clearly differentiates the present strategy from other cross-coupling strategies. Most importantly, our method enables the late-stage conjugation of bioactive (hetero)arylamines with nicotinates and nicotinamides and allows access to the previously unexplored chemical space for biomedical research. Vitamin B3 derivatives display a range of biological activities. Here, the authors report the synthesis of meta-aminoaryl nicotinates, derivatives of vitamin B3, and their late-stage conjugation with (hetero)arylamines, ultimately expanding the chemical space for biomedical research.
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Affiliation(s)
- Begur Vasanthkumar Varun
- CRI Center for Chemical Proteomics, Department of Chemistry, Seoul National University, Seoul, 08826, Republic of Korea
| | - Kannan Vaithegi
- CRI Center for Chemical Proteomics, Department of Chemistry, Seoul National University, Seoul, 08826, Republic of Korea
| | - Sihyeong Yi
- CRI Center for Chemical Proteomics, Department of Chemistry, Seoul National University, Seoul, 08826, Republic of Korea
| | - Seung Bum Park
- CRI Center for Chemical Proteomics, Department of Chemistry, Seoul National University, Seoul, 08826, Republic of Korea.
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Qian Y, Wang P, Rao L, Song C, Yin H, Wang X, Zhou G, Nötzel R. Electric dipole of InN/InGaN quantum dots and holes and giant surface photovoltage directly measured by Kelvin probe force microscopy. Sci Rep 2020; 10:5930. [PMID: 32246077 PMCID: PMC7125200 DOI: 10.1038/s41598-020-62820-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 03/17/2020] [Indexed: 11/09/2022] Open
Abstract
We directly measure the electric dipole of InN quantum dots (QDs) grown on In-rich InGaN layers by Kelvin probe force microscopy. This significantly advances the understanding of the superior catalytic performance of InN/InGaN QDs in ion- and biosensing and in photoelectrochemical hydrogen generation by water splitting and the understanding of the important third-generation InGaN semiconductor surface in general. The positive surface photovoltage (SPV) gives an outward QD dipole with dipole potential of the order of 150 mV, in agreement with previous calculations. After HCl-etching, to complement the determination of the electric dipole, a giant negative SPV of -2.4 V, significantly larger than the InGaN bandgap energy, is discovered. This giant SPV is assigned to a large inward electric dipole, associated with the appearance of holes, matching the original QD lateral size and density. Such surprising result points towards unique photovoltaic effects and photosensitivity.
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Affiliation(s)
- Yinping Qian
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, P. R. China
| | - Peng Wang
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, P. R. China.,National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou, 510006, P. R. China
| | - Lujia Rao
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, P. R. China
| | - Changkun Song
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, P. R. China
| | - Hongjie Yin
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, P. R. China
| | - Xingyu Wang
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, P. R. China
| | - Guofu Zhou
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, P. R. China. .,National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou, 510006, P. R. China. .,Academy of Shenzhen Guohua Optoelectronics, Shenzhen, 518110, P. R. China.
| | - Richard Nötzel
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, P. R. China. .,National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou, 510006, P. R. China.
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Rather RA, Lo IMC. Photoelectrochemical sewage treatment by a multifunctional g-C 3N 4/Ag/AgCl/BiVO 4 photoanode for the simultaneous degradation of emerging pollutants and hydrogen production, and the disinfection of E. coli. WATER RESEARCH 2020; 168:115166. [PMID: 31634707 DOI: 10.1016/j.watres.2019.115166] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Revised: 10/02/2019] [Accepted: 10/06/2019] [Indexed: 05/03/2023]
Abstract
This study describes the photoelectrochemical (PEC) treatment of authentic sewage from Hong Kong for H2 production and degradation of emerging pollutants (EP's) simultaneously, and disinfection of E. coli. The g-C3N4/Ag/AgCl/BiVO4 (CAB-1) coated thin film acted as the photoanode in a three-electrode configuration PEC cell and real sewage as the electrolyte. Electrochemical studies revealed the near reversible, diffusion-controlled and high electron transfer reaction at the electrode-electrolyte surface. For CAB-1, the achieved photocurrent density was 0.1-0.2 mA cm-2 at 1.23 V vs. RHE exhibiting the highest PEC degradation efficiency (11.15% h-1 cm-2) compared to other base materials like g-C3N4/BiVO4 (6.88% h-1 cm-2) or Ag/AgCl/BiVO4 (4.06% h-1 cm-2). During the same reaction, the evolved 118 μmol of H2 gas corresponds to a Faradic efficiency of 69.38%. The composition of sewage was found to influence the overall PEC efficiency. The higher amount of total suspended solids, turbidity, and anionic species decreased the efficiency while as the other parameters like alkaline pH increased the PEC efficiency. Photo-electrochemically, the CAB-1 also effectively disinfected the E. coli present in the sewage with a final discharge of ≤1000 CFU/mL which is within the permissible discharge limits (≤1500 CFU/mL), in Hong Kong.
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Affiliation(s)
- Rayees Ahmad Rather
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Irene M C Lo
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China; Institute for Advanced Study (IAS), The Hong Kong University of Science and Technology, Hong Kong, China.
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Spatial Surface Charge Engineering for Electrochemical Electrodes. Sci Rep 2019; 9:14489. [PMID: 31601966 PMCID: PMC6787049 DOI: 10.1038/s41598-019-51048-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 09/24/2019] [Indexed: 01/27/2023] Open
Abstract
We introduce a novel concept for the design of functional surfaces of materials: Spatial surface charge engineering. We exploit the concept for an all-solid-state, epitaxial InN/InGaN-on-Si reference electrode to replace the inconvenient liquid-filled reference electrodes, such as Ag/AgCl. Reference electrodes are universal components of electrochemical sensors, ubiquitous in electrochemistry to set a constant potential. For subtle interrelation of structure design, surface morphology and the unique surface charge properties of InGaN, the reference electrode has less than 10 mV/decade sensitivity over a wide concentration range, evaluated for KCl aqueous solutions and less than 2 mV/hour long-time drift over 12 hours. Key is a nanoscale charge balanced surface for the right InGaN composition, InN amount and InGaN surface morphology, depending on growth conditions and layer thickness, which is underpinned by the surface potential measured by Kelvin probe force microscopy. When paired with the InN/InGaN quantum dot sensing electrode with super-Nernstian sensitivity, where only structure design and surface morphology are changed, this completes an all-InGaN-based electrochemical sensor with unprecedented performance.
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