Construction of an Ohmic Junction Between Bimetallic Sulfide NiMnS and Maple‐Leaf‐Shaped CdS and Its Enhanced Photocatalytic Hydrogen Evolution via Strong Electron Coupling

ABSTRACT In order to investigate the influence of the ohmic junction formed at the interface between the bimetallic sulfide NiMnS and maple‐leaf CdS on photocatalytic hydrogen evolution performance, this work employed a simple hydrothermal method to synthesise maple‐leaf CdS and granular NiMnS. The optimized composite material (15NiMnS/CdS) achieved an exceptional hydrogen evolution rate of 34.83 mmol·g −1 ·h −1 under visible light illumination within 5 h, surpassing the rates of CdS alone and NiMnS alone by 5.44‐fold and 530.70‐fold, respectively. The superior photocatalytic hydrogen evolution performance originates from the fact that the Fermi level of the metal‐like catalyst NiMnS is higher than that of the semiconductor catalyst CdS. This allows the two to form an ohmic junction after contact, creating a strong electronic coupling interface. Electron enrichment occurs at CdS, which inhibits electron–hole recombination and enables electrons to engage in the photocatalytic process efficiently, thus improving its photocatalytic hydrogen evolution ability. The incorporation of NiMnS co‐catalyst increased the CdS charge separation efficiency from 18.67% to 68.16%, thereby improving the catalyst's reaction kinetics and enhancing the photocatalytic hydrogen generation rate. This study presents an example of engineering transition‐metal sulfide‐based Ohmic‐contact structures and enhancing photocatalytic hydrogen evolution performance through strong electronic coupling.