Gold Nanoclusters as Electrocatalysts: Atomic Level Understanding from Fundamentals to Applications

Recently, gold nanoclusters (Au NCs) have become more popular as their structure–property relationships start to rival those of conventional Au NPs. The molecular-type energy transition and quantum confinement effects of Au NCs are fundamentally different from those of Au NPs. Because of these intriguing features, Au NCs are gaining special attention in catalysis research and are being used as model catalysts to understand catalytic properties and structures at the atomic level. Although catalysis research is a longstanding discipline, the fundamental insights into structure–property relationships at the atomic level, such as reaction mechanism/activation at the catalyst surface and identification of actives sites, remain largely unexplored. Atomically precise Au NCs can provide access to such information because of their exact molecular information, monodisperse nature, molecule-like properties, and well-resolved atomic structure from X-ray crystallography, akin to protein structures in enzyme-based catalysis. This accurate data also provides essential information for computational investigations. In this Perspective, we summarize the recent progress made using Au NCs as electrocatalytic materials for oxygen reduction, water electrocatalysis, and electrochemical reduction of carbon dioxide, and we discuss challenges to overcome existing limitations. We hope that our Perspective motivates more researchers to investigate different aspects of Au NCs toward a better understanding of the structure–performance correlations in catalysis.