(Invited) Semiconductor Surface-Controlled Photocatalysis

Photo-induced charge transfer has been found to depend strongly on the exposed semiconductor surfaces. For example, {110}-bound Cu2O rhombic dodecahedra show a high photocatalytic activity, but {100}-terminated Cu2O cubes are inactive. Photocatalytic behaviors of Cu2O-based semiconductor heterostructures, such as Cu2O-ZnO and Cu2O-ZnS composites, can both enhance and suppress photocatalytic activity depending on the contacting planes at the heterojunction. Interestingly, Cu2O photocatalytic activity can be greatly enhanced by functionalizing with conjugated molecules through surface band structure tuning, turning inert cubes to possess a superior photocatalytic activity. More recently, the photogenerated superoxide radicals can be used in some organic reactions, and the crystal surface is naturally linked to the product yields.