High-Performance Hollow MoC/N-Doped Carbon Cocatalysts for Enhanced Photocatalytic Hydrogen Evolution via CdS Coupling

Molybdenum carbide (MoC) has attracted significant attention as a cocatalyst for photocatalytic hydrogen evolution. However, facile and scalable methods to synthesize hollow MoC materials with high specific surface areas remain limited. Herein, hollow-structured MoC/N-doped carbon (MCN) cocatalysts were innovatively synthesized via high-temperature calcination of MoO3-containing polydopamine (MoO3/PDA) precursors. These MCN materials were subsequently coupled with CdS through a solvothermal process to construct composite photocatalysts (MCN/CdS, denoted as MCS). Under simulated sunlight irradiation (AM 1.5G), the optimized MCS catalyst achieved an exceptional photocatalytic hydrogen evolution rate of 26.4 mmol·g–1·h–1, which is 10.8 times higher than that of the benchmark Pt/CdS catalyst. The MCS catalyst also demonstrated outstanding stability, maintaining efficient hydrogen production after 20 h of continuous illumination. The superior performance of MCS stems from two key advantages of the MCN cocatalyst: (i) its high specific surface area enhances CdS dispersion and provides abundant active sites for hydrogen evolution; (ii) the N-doped carbon matrix broadens light absorption and facilitates charge carrier transport. This work introduces an effective approach for the rapid and mild synthesis of ultrahigh surface area hollow nanospherical transition-metal carbons, providing valuable insights for advanced photocatalytic systems.