Construction of S-scheme CoMn2O4/ZnCdS p–n heterojunction for enhanced photocatalytic hydrogen production

Abstract

Constructing p–n heterojunctions serves as a powerful strategy for boosting the generation and separation of photogenerated carriers, thereby promoting the photocatalytic production of hydrogen. This step is crucial for optimizing the performance of the photocatalytic hydrogen production. In the current research, a p–n type heterojunction photocatalyst, ZnCdS/CoMn₂O₄, with S-scheme heterojunction characteristics, was successfully synthesized. The optimized composite ZnCdS/CoMn₂O₄ demonstrated a 4.76-fold increase in hydrogen production compared to ZnCdS alone and exhibited excellent catalytic activity. Further characterization using techniques, like in situ XPS and DFT calculations, revealed that the p–n type heterojunction effectively promoted the separation of photogenerated electron–hole pairs, a key step for efficient hydrogen production. Furthermore, the enhanced redox capacity of the composite photocatalyst was confirmed by electron paramagnetic resonance analysis. The broadened light absorption range of the composite photocatalyst was also demonstrated, providing an ample number of active sites. This study offers insights into p–n photocatalysts with S-scheme heterojunction properties and proposes a promising approach for designing p–n heterojunctions to enhance photocatalytic hydrogen production.