The predisposition circulation of the anode and cathode in the PEC total reaction cell resembles 2 trays of the balance, and the fulcrum represents the short-circuit potential of the PEC cell. Credit: Science China PressOver the last years, the photoelectrochemical (PEC) process for general water-splitting (OWS) has seen detailed advancement, especially in the locations of new drivers, approaches of characterization,, and response systems. When comparing the hydrogen evolution response (HER) to the oxygen evolution response (OER), the latter is considered the more tough aspect of OWS, primarily due to its slow kinetics.To reduce the bias consumption of photoanodes, a series of OER alternative half-reactions have been developed, such as alcohols, urea, and ammonia oxidation responses. The ultimate objective of photochemistry is to fabricate an effective two-electrode objective PEC cell. Many of the previous research studies only focused on the properties of the working electrode in the three-electrode cell, while the polarization on the counter electrode was mostly ignored. The synergistic mechanism in between anodic oxidation and cathodic reduction half-reactions is still unclear.a) Schematic of bias distribution measurements. b– e) Bias circulation in PEC OWS cells with different photoanodes and f) matching OWS activation pathways. Credit: Science China PressRecently, Professor Yuchao Zhangs group proposed an experimental technique to measure the bias circulation in a two-electrode PEC cell, methodically studying the bias distribution between representative photoanodes and Pt cathodes in PEC OWS cells. For the very first time, they showed that the OER half-reaction is not constantly the rate-limiting factor of the OWS, and the bias intake of electrodes depends on the photovoltage of the photoanode and the Fermi level of the cathode.Further studies by utilizing Ni/n-Si as the model photoanode revealed that the bias distribution in the total reaction can be effectively changed by tuning the electrolyte pH and combined half-reactions. Accordingly, they proposed a descriptor to examine the compatibility between numerous half-reactions, which explained a basic method for designing an effective PEC overall reaction cell. Inspired by this, they made an objective PEC cell consisting just of a Ni/n-Si photoanode and a Pt cathode with a photocurrent of 5.3 ± 0.2 mA cm − 2. Reference: “Bias circulation and regulation in photoelectrochemical overall water-splitting cells” by Kun Dang, Siqin Liu, Lei Wu, Daojian Tang, Jing Xue, Jiaming Wang, Hongwei Ji, Chuncheng Chen, Yuchao Zhang and Jincai Zhao, 06 February 2024, National Science Review.DOI: 10.1093/ nsr/nwae053.
