Zhang Xiuxiu, Yang Chenyu, Gong Chen, Liu Meihuan, Zhou Wanlin, Su Hui, Yu Feifan, Hu Fengchun, Liu Qinghua, Wei Shiqiang
National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, 230029, Anhui, P. R. China.
Key Laboratory of Light Energy Conversion Materials of Hunan Province College, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, 410081, Hunan, P. R. China.
Angew Chem Int Ed Engl. 2023 Aug 14;62(33):e202308082. doi: 10.1002/anie.202308082. Epub 2023 Jul 7.
Synthesis of highly active and durable oxygen evolution reaction (OER) catalysts applied in acidic water electrolysis remains a grand challenge. Here, we construct a type of high-loading iridium single atom catalysts with tunable d-band holes character (h-HL-Ir SACs, ∼17.2 wt % Ir) realized in the early OER operation stages. The in situ X-ray absorption spectroscopy reveals that the quantity of the d-band holes of Ir active sites can be fast increased by 0.56 unit from the open circuit to a low working potential of 1.35 V. More remarkably, in situ synchrotron infrared and Raman spectroscopies demonstrate the quick accumulation of *OOH and *OH intermediates over holes-modulated Ir sites in the early reaction voltages, achieving a rapid OER kinetics. As a result, this well-designed h-HL-Ir SACs exhibits superior performance for acidic OER with overpotentials of 216 mV @10 mA cm and 259 mV @100 mA cm , corresponding to a small Tafel slope of 43 mV dec . The activity of catalyst shows no evident attenuation after 60 h operation in acidic environment. This work provides some useful hints for the design of superior acidic OER catalysts.
合成适用于酸性水电解的高活性且耐用的析氧反应（OER）催化剂仍然是一个巨大的挑战。在此，我们构建了一种在OER运行早期阶段实现的具有可调d带空穴特征的高负载铱单原子催化剂（h-HL-Ir SACs，Ir含量约为17.2 wt%）。原位X射线吸收光谱表明，Ir活性位点的d带空穴数量可在从开路到1.35 V的低工作电位下快速增加0.56个单位。更值得注意的是，原位同步辐射红外和拉曼光谱表明，在早期反应电压下，OOH和OH中间体在空穴调制的Ir位点上快速积累，实现了快速的OER动力学。因此，这种精心设计的h-HL-Ir SACs在酸性OER中表现出优异的性能，在10 mA cm时过电位为216 mV，在100 mA cm时过电位为259 mV，对应于43 mV dec的小塔菲尔斜率。在酸性环境中运行60小时后，催化剂的活性没有明显衰减。这项工作为设计优异的酸性OER催化剂提供了一些有用的线索。
