Engineering single-atom catalysts for efficient electrochemical reaction in the cathode of fuel cells and water electrolysis

Abstract

Single atom catalysts, with their distinct electrochemical properties different from the metal nano-catalysts, are getting attention in the hydrogen society as a new type of catalytic material in electrochemical devices for achieving carbon-neutralization. In particular, single atom catalysts composed of non-platinum group metals have the potential to replace platinum catalysts in fuel cell electrodes. It can also effectively reduce the usage of precious metals at the material level by maximizing their utilization efficiency when using the precious metals. In this dissertation, we investigate engineering single-atom catalysts for oxygen reduction reaction in fuel cells and hydrogen evolution reaction in water electrolysis, focusing on the catalyst design and reaction mechanisms for high efficiency. The electrochemical properties and structure of the materials are discussed based on electrochemical analysis and synchrotron radiation-based techniques. Each reaction mechanism is elucidated using the first-principles density functional theory. This dissertation provides deeper insights into developing catalytic materials using single atom catalysts for crucial electrochemical reactions in achieving hydrogen society.