上海科技大学黄逸凡团队报道了水在金上氧化的光电化学质子耦合电子转移的电子转移中间体的原位光谱鉴定。相关研究成果发表在2023年1月17日出版的《美国化学会杂志》。

在分子水平上对电子和质子转移解耦的实验进行阐明，对于彻底理解非均相（光）电化学质子耦合电子转移-水氧化的动力学至关重要。

该文中，研究人员通过原位微光电化学表面增强拉曼光谱（SERS）和环境压力X射线光电子能谱，揭示了Au（Au–OH⁺）上带正电的表面含氧物种的电子转移中间体及其与水氧化速率的关系。在水氧化的中间阶段，在激光功率密度相关测量中，Au–OH物种振动的特征性蓝移被归因于水氧化中Au–OH⁺的光诱导产生。在变温SERS测量中，随着温度的升高，根据Au-OH物种的振动频率，光热效应被排除。密度泛函理论计算证明，频率蓝移来自带正电的Au-OH物种。与光电流相关的频率蓝移表明，Au–OH⁺是水氧化过程中通过电子和质子转移分离的关键电子转移中间体。

附：英文原文

Title: In Situ Spectroscopic Identification of the Electron-Transfer Intermediates of Photoelectrochemical Proton-Coupled Electron Transfer of Water Oxidation on Au

Author: Li-Wen Wu, Chiyan Liu, Yong Han, Yi Yu, Zhi Liu, Yi-Fan Huang

Issue&Volume: January 17, 2023

Abstract: Experimental elucidation of the decoupling of electron and proton transfer at a molecular level is essential for thoroughly understanding the kinetics of heterogeneous (photo)electrochemical proton-coupled electron transfer water oxidation. Here we illustrate the electron-transfer intermediates of positively charged surface oxygenated species on Au (Au–OH+) and their correlations with the rate of water oxidation by in situ microphotoelectrochemical surface-enhanced Raman spectroscopy (SERS) and ambient-pressure X-ray photoelectron spectroscopy. At the intermediate stage of water oxidation, a characteristic blue shift of the vibration of Au–OH species in laser-power-density-dependent measurements was assigned to the light-induced production of Au–OH+ in water oxidation. The photothermal effect was excluded according to the vibrational frequencies of Au–OH species as the temperature was increased in a variable-temperature SERS measurement. Density functional theory calculations evidenced that the frequency blue shift is from the positively charged Au–OH species. The photocurrent-dependent frequency blue shift indicated that Au–OH+ is the key electron-transfer intermediate in water oxidation by decoupled electron and proton transfer.

DOI: 10.1021/jacs.2c11882

Source: https://pubs.acs.org/doi/10.1021/jacs.2c11882