Ultrasmall MoOx Clusters as a Novel Cocatalyst for Photocatalytic Hydrogen Evolution

Abstract To enhance the performance of semiconductor photocatalysts, cocatalysts are used to accelerate surface reactions. Herein, ultrasmall molybdenum–oxygen (MoO x ) clusters are developed as a novel non‐noble cocatalyst, which significantly promotes the photocatalytic hydrogen generation rate of CdS nanowires (NWs). As indicated by extended X‐ray absorption fine structure analysis, direct bonds are formed between CdS NWs and MoO x clusters, which guarantee the migration of photo‐generated charge carriers. Moreover, the MoO x clusters induce deep electron trap states owing to the unique atomic arrangement and configuration with the generation of long‐lived electrons to enhance the activity. These findings may guide the design of efficient cocatalytic materials for solar water splitting and open a new avenue toward practical applications of ultrasmall clusters.