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Magnetron Sputtered Al Co-Doped with Zr-Fe2O3 Photoanode with Fortuitous Al2O3 Passivation Layer to Lower the Onset Potential for Photoelectrochemical Solar Water Splitting. Catalysts 2022. [DOI: 10.3390/catal12111467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In this paper, we investigate the magnetron sputtering deposition of an Al-layer on Zr-doped FeOOH (Zr-FeOOH) samples to fabricate a Zr/Al co-doped Fe2O3 (Al-Zr/HT) photoanode. An Al-layer is deposited onto Zr-FeOOH through magnetron sputtering and the thickness of the Al deposition is regulated by differing the sputtering time. Electrochemical impedance spectroscopy, intensity-modulated photocurrent spectroscopy, Mott-Schottky and time-resolved photoluminescence spectra analyses were used to study, in depth, the correlations between sputtered Al-layer thicknesses and PEC characteristics. High-temperature quenching (800 °C) assists in diffusing the Al3+ in the bulk of the Zr-doped Fe2O3 photoanode, whilst an unintended Al2O3 passivation layer forms on the surface. The optimized Al-Zr/HT photoelectrode achieved 0.945 mA/cm2 at 1.0 VRHE, which is 3-fold higher than that of the bare Zr/HT photoanode. The Al2O3 passivation layer causes a 100 mV cathodic shift in the onset potential. Al co-doping improved the donor density, thus reducing the electron transit time. In addition, the passivation effect of the Al2O3 layer ameliorated the surface charge transfer kinetics. The Al2O3 passivation layer suppressed the surface charge transfer resistance, consequently expediting the hole migration from photoanode to electrolyte. We believe that the thickness-controlled Al-layer sputtering approach could be applicable for various metal oxide photoanodes to lower the onset potential.
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Chen Z, Yang H, Kang Z, Driess M, Menezes PW. The Pivotal Role of s-, p-, and f-Block Metals in Water Electrolysis: Status Quo and Perspectives. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2108432. [PMID: 35104388 DOI: 10.1002/adma.202108432] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 01/19/2022] [Indexed: 05/27/2023]
Abstract
Transition metals, in particular noble metals, are the most common species in metal-mediated water electrolysis because they serve as highly active catalytic sites. In many cases, the presence of nontransition metals, that is, s-, p-, and f-block metals with high natural abundance in the earth-crust in the catalytic material is indispensable to boost efficiency and durability in water electrolysis. This is why alkali metals, alkaline-earth metals, rare-earth metals, lean metals, and metalloids receive growing interest in this research area. In spite of the pivotal role of these nontransition metals in tuning efficiency of water electrolysis, there is far more room for developments toward a knowledge-based catalyst design. In this review, five classes of nontransition metals species which are successfully utilized in water electrolysis, with special emphasis on electronic structure-catalytic activity relationships and phase stability, are discussed. Moreover, specific fundamental aspects on electrocatalysts for water electrolysis as well as a perspective on this research field are also addressed in this account. It is anticipated that this review can trigger a broader interest in using s-, p-, and f-block metals species toward the discovery of advanced polymetal-containing electrocatalysts for practical water splitting.
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Affiliation(s)
- Ziliang Chen
- Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou, 215123, P. R. China
- Department of Chemistry, Metalorganics and Inorganic Materials, Technische Universität Berlin, Straße des 17 Juni 135, Sekr. C2, 10623, Berlin, Germany
| | - Hongyuan Yang
- Department of Chemistry, Metalorganics and Inorganic Materials, Technische Universität Berlin, Straße des 17 Juni 135, Sekr. C2, 10623, Berlin, Germany
| | - Zhenhui Kang
- Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou, 215123, P. R. China
| | - Matthias Driess
- Department of Chemistry, Metalorganics and Inorganic Materials, Technische Universität Berlin, Straße des 17 Juni 135, Sekr. C2, 10623, Berlin, Germany
| | - Prashanth W Menezes
- Department of Chemistry, Metalorganics and Inorganic Materials, Technische Universität Berlin, Straße des 17 Juni 135, Sekr. C2, 10623, Berlin, Germany
- Material Chemistry Group for Thin Film Catalysis - CatLab, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Str. 15, 12489, Berlin, Germany
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Jeong IK, Mahadik MA, Hwang JB, Chae WS, Choi SH, Jang JS. Lowering the onset potential of Zr-doped hematite nanocoral photoanodes by Al co-doping and surface modification with electrodeposited Co-Pi. J Colloid Interface Sci 2021; 581:751-763. [PMID: 32818679 DOI: 10.1016/j.jcis.2020.08.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 07/31/2020] [Accepted: 08/02/2020] [Indexed: 10/23/2022]
Abstract
Herein, in situ zirconium-doped hematite nanocoral (Zr-Fe2O3 (I) NC) photoanode was prepared via a specially designed diluted hydrothermal approach and modified with Al3+ co-doping and electrodeposited cobalt-phosphate ("Co-Pi") cocatalyst. Firstly, an unintentional in situ Zr-Fe2O3 (I)) NC photoanode was synthesized, which achieved an optimum photocurrent density of 0.27 mA/cm2 at 1.0 V vs. RHE but possessed a more positively shifted onset potential than conventionally prepared hematite nanorod photoelectrodes. An optimized amount of aluminum co-doping suppresses the bulk as well as surface defects, which causes a negative shift in the onset potential from 0.85 V to 0.8 V vs. RHE and enhances the photocurrent density of Zr-Fe2O3(I) NC from 0.27 mA/cm2 to 0.7 mA/cm2 at 1.0 V vs. RHE. The electrodeposited Co-Pi modification further reduce the onset potential of Al co-doped Zr-Fe2O3(I) NC to 0.58 V vs. RHE and yield a maximum photocurrent of 1.1 mA/cm2 at 1.0 V vs. RHE (1.8 mA/cm2 at 1.23 V vs RHE). The improved photocurrent at low onset potential can be attributed to synergistic effect of Al co-doping and Co-Pi surface modification. Further, during photoelectrochemical water-splitting, a 137 and 67 μmol of hydrogen (H2) and oxygen (O2) evolution was achieved over the optimum Co-Pi-modified Al-co-doped Zr-Fe2O3(I) NC photoanode within 6 h. The proposed charge transfer mechanism in optimum Co-Pi-modified Alco-doped Zr-Fe2O3(I) NC photoanodes during the photoelectrochemical water splitting was also studied.
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Affiliation(s)
- In Kwon Jeong
- Division of Biotechnology, Safety, Environment and Life Science Institute, College of Environmental and Bioresource Sciences, Chonbuk National University, Iksan 570-752, Republic of Korea
| | - Mahadeo A Mahadik
- Division of Biotechnology, Safety, Environment and Life Science Institute, College of Environmental and Bioresource Sciences, Chonbuk National University, Iksan 570-752, Republic of Korea
| | - Jun Beom Hwang
- Division of Biotechnology, Safety, Environment and Life Science Institute, College of Environmental and Bioresource Sciences, Chonbuk National University, Iksan 570-752, Republic of Korea
| | - Weon-Sik Chae
- Daegu Center, Korea Basic Science Institute, Daegu 41566, Republic of Korea
| | - Sun Hee Choi
- Pohang Accelerator Laboratory, POSTECH, Pohang 37673, Republic of Korea.
| | - Jum Suk Jang
- Division of Biotechnology, Safety, Environment and Life Science Institute, College of Environmental and Bioresource Sciences, Chonbuk National University, Iksan 570-752, Republic of Korea.
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Chen X, Fu Y, Hong L, Kong T, Shi X, Wang G, Qu L, Shen S. Interface and surface engineering of hematite photoanode for efficient solar water oxidation. J Chem Phys 2020; 152:244707. [DOI: 10.1063/5.0009072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Xiangyan Chen
- International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049, China
| | - Yanming Fu
- International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049, China
| | - Liu Hong
- National Key Lab of Science and Technology on LRE, Xi’an Aerospace Propulsion Institute, Xi’an, Shaanxi 710100, China
| | - Tingting Kong
- College of Chemistry and Chemical Engineering, Xi’an Shiyou University, Xi’an, Shaanxi 710054, China
| | - Xiaobo Shi
- National Key Lab of Science and Technology on LRE, Xi’an Aerospace Propulsion Institute, Xi’an, Shaanxi 710100, China
| | - Guangxu Wang
- National Key Lab of Science and Technology on LRE, Xi’an Aerospace Propulsion Institute, Xi’an, Shaanxi 710100, China
| | - Le Qu
- College of Chemistry and Chemical Engineering, Xi’an Shiyou University, Xi’an, Shaanxi 710054, China
- State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu University of Technology, Chengdu, Sichuan 610059, China
| | - Shaohua Shen
- International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049, China
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