Observation of 4th-order water oxidation kinetics by time-resolved photovoltage spectroscopy
Xiaogang Yang,
Zhi Zheng,
Jundie Hu,
Jiafu Qu,
Dekun Ma,
Jingsha Li,
Chunxian Guo,
Chang Ming Li
Affiliations
Xiaogang Yang
Institute of Materials Science and Devices, School of Material Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, PR China; Key Laboratory of Micro-Nano Materials for Energy Storage and Conversion of Henan Province, Institute of Surface Micro and Nano Materials, Xuchang University, Henan 461000, P R China; Corresponding author
Zhi Zheng
Key Laboratory of Micro-Nano Materials for Energy Storage and Conversion of Henan Province, Institute of Surface Micro and Nano Materials, Xuchang University, Henan 461000, P R China
Jundie Hu
Institute of Materials Science and Devices, School of Material Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, PR China
Jiafu Qu
Institute of Materials Science and Devices, School of Material Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, PR China
Dekun Ma
Zhejiang Key Laboratory of Alternative Technologies for Fine Chemicals Process, Shaoxing University, Shaoxing 312000, PR China
Jingsha Li
Institute of Materials Science and Devices, School of Material Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, PR China
Chunxian Guo
Institute of Materials Science and Devices, School of Material Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, PR China; Jiangsu Key Laboratory for Micro and Nano Heat Fluid Flow Technology and Energy Application, Suzhou 215009, PR China
Chang Ming Li
Institute of Materials Science and Devices, School of Material Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, PR China; Jiangsu Key Laboratory for Micro and Nano Heat Fluid Flow Technology and Energy Application, Suzhou 215009, PR China; Institute of Clean Energy & Advanced Materials, Southwest University, Chongqing 400715, PR China
Summary: Artificial photo-driven water oxidation has been proposed over half a century through a four-charge involved multiple-step oxygen evolution process. However, the knowledge of the intrinsic activity, such as the rate-law of the water oxidation reactions, has been inadequately studied. Up to date, the highest order reported is the third one under photoelectrochemical condition. In this work, we identified the fourth-order charge decay reactions on hematite by using a time-resolved surface photovoltage probe technique. A theoretical turnover frequency (TOF) > 100 nm−2·s−1 can be expected for O2 molecules when the hole density >0.1 nm−2. This work demonstrates a facile and robust method to investigate the high-order reaction kinetics. More excitingly, this research built the bridge between the rate-law, rate-determining step, and energy barrier of intermediates.
