This project set out to investigate the role of individual atoms in light-driven chemical reactions, a field known as photocatalysis. Photocatalysis is a promising technology for clean energy because it uses sunlight to power chemical reactions, for example to split water into hydrogen and oxygen or to convert carbon dioxide into useful fuels. However, despite its potential, photocatalysis remains poorly understood on a fundamental level. Many questions remain about how light energy is absorbed, how charges move inside a material, and how molecules interact with the surface.
A particularly exciting avenue is the use of so-called single-atom catalysts: semiconductor materials that carry individual metal atoms anchored to their surface. These atoms can act as highly efficient reaction centers. Yet, because the field is new, little is known about their precise function. Our project addressed this knowledge gap by studying photocatalysis under highly controlled conditions, using advanced physical chemistry tools to “zoom in” on the atomic scale.