Liquid-Solid and Solid-Solid Interfaces in Electrocatalysis from First Principles

Abstract

Understanding the electrochemical reactions at Liquid-Solid interfaces has been a great and long-term interest but challenge for both experimentalists and theorists. Even though tremendous advances have made through numerous techniques, significant uncertainties relating to the reaction intermediates and reaction mechanism remain. The problem is further complicated when a Solid-Solid interface has been formed either through electrodeposition or de-alloying, as the corresponding interface structures and consequently surface structures of the catalysts are still largely unknown. In this talk, we will review the methodologies we have recently developed to de-convolute those effects, including a synergistic strategy towards highly accurate prediction of Pourbaix diagram of transition metal (hydroxy)oxides, a simple Morie pattern technique for screening Solid-Solid interface, ab initio molecular simulation to sample Liquid-Solid interfaces and X-ray Photoelectron Spectroscopy simulation to identify the oxygenated species at Liquid-Solid interface. Next, using monolayer layer (hydroxy)oxide-metal interface as an example, we will demonstrate how the combination of the above techniques could identify the stable phases under various electrochemical conditions. As a case study, we will show the bi-functional role of the interface in promoting hydrogen evolution reaction (HER). As another example, we will show the development of the metal-metal interface during the de-alloying process of Pt-based alloy electrocatalysts. Finally, we will show the applications of these understandings for the design of new catalysts with improved performances for electrolysis and fuel cell applications. [1] L. Wang, Y. Zhu, Z. Zeng, C. Lin, M. Giroux, L. Jiang, Y. Han, J. Greeley, C. Wang, and J. Jin, Nano Energy 31, 456 (2017). [2] Z. Zeng and J. Greeley, Nano Energy 29, 369 (2016). [3] Y. Ha, Z. Zeng, Y. Cohen, J. Greeley, and A. A. Gewirth, J. Phys. Chem. C 120, 8674 (2016). [4] Z. Zeng, M. K. Y. Chan, Z.-J. Zhao, J. Kubal, D. Fan, and J. Greeley, J. Phys. Chem. C 119, 18177 (2015).