Noble-metal-free Ni(dmgH)2/CdS nanocomposite for enhanced photocatalytic H2 generation

In this study, we report an economic and noble-metal-free photosynthetic system of Ni(dmgH)2/CdS composites (dmgH = dimethylglyoxime). This system, consisting of CdS as a photocatalyst and Ni(dmgH)2 as a co-catalyst, exhibits enhanced photoresponse, accelerated charge transfer, facilitating the separation of electrons and holes, and efficient hydrogen evolution under visible light. It was found that the catalytic efficiency of CdS was significantly influenced by the loading amount of Ni(dmgH)2. An optimum activity was achieved at 10 wt% Ni (dmgH)2, resulting a stable hydrogen generation rate of 32.744 mmol h- 1 g- 1. This rate is nearly 98 times higher than that of bare CdS under similar conditions, indicating that Ni(dmgH)2 can be a highly efficient noble-metalfree co-catalyst for photocatalytic hydrogen evolution with CdS. The mechanism for the hydrogen evolution of the Ni(dmgH)2/CdS composites was also proposed. This study demonstrates that the combination CdS semiconductor with small proportion of transition-metal-based co-catalyst may provide a reliable platform for a stable, earth-abundant, and low-cost system for solar-to-hydrogen conversion, paving the way for promising advancements in green energy research.