Stoerzinger Kelsey A, Favaro Marco, Ross Philip N, Yano Junko, Liu Zhi, Hussain Zahid, Crumlin Ethan J
Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory , Richland, Washington 99352, United States.
Advanced Light Source, Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, California 94720, United States.
J Phys Chem B. 2018 Jan 18;122(2):864-870. doi: 10.1021/acs.jpcb.7b06953. Epub 2017 Dec 6.
Understanding the surface chemistry of electrocatalysts in operando can bring insight into the reaction mechanism, and ultimately the design of more efficient materials for sustainable energy storage and conversion. Recent progress in synchrotron based X-ray spectroscopies for in operando characterization allows us to probe the solid/liquid interface directly while applying an external potential, applied here to the model system of Pt in alkaline electrolyte for the hydrogen evolution reaction (HER). We employ ambient pressure X-ray photoelectron spectroscopy (AP-XPS) to identify the oxidation and reduction of Pt-oxides and hydroxides on the surface as a function of applied potential, and further assess the potential for hydrogen adsorption and absorption (hydride formation) during and after the HER. This new window into the surface chemistry of Pt in alkaline electrolyte brings insight into the nature of the rate limiting step, the extent of H ad/absorption, and its persistence at more anodic potentials.
了解电催化剂在工作状态下的表面化学性质有助于深入了解反应机理，并最终为可持续能源存储和转换设计出更高效的材料。基于同步加速器的X射线光谱技术在原位表征方面的最新进展使我们能够在施加外部电势时直接探测固/液界面，在此将其应用于碱性电解质中铂用于析氢反应（HER）的模型体系。我们采用常压X射线光电子能谱（AP-XPS）来确定表面上铂氧化物和氢氧化物随施加电势的氧化和还原情况，并进一步评估析氢反应期间及之后氢吸附和吸收（氢化物形成）的可能性。这个关于碱性电解质中铂表面化学性质的新窗口为速率限制步骤的本质、氢吸附/吸收的程度及其在更正极电势下的持续性提供了深入见解。
