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.