C3N5 nanosheets decorated with Cu-Pt alloy nanoparticles toward efficient photocatalytic hydrogen evolution

The construction of highly efficient photocatalysts for generating high-purity hydrogen (H2) through a sustainable water decomposition system is a feasible option to replace conventional non-renewable energy resources. Here, we report a simple chemical reduction approach to embed Cu-Pt alloy nanocrystals on the C3N5 (CN) matrix, creating a Schottky heterojunction. The structural morphology, crystal phase, light-harvesting capacity, and photo-electrochemical properties of as-prepared heterostructures were investigated. The uniformly anchored Cu-Pt alloy nanocrystals improve the photocatalytic H2 evolution (PHE) activity by promoting the separation and transfer of photogenerated carriers and inhibiting recombination. Meanwhile, the alloyed nanocrystals strengthen the absorption of incident light energy, inducing photothermal energy. This improves the charge carrier separation and promotes the surface reaction kinetics. The PHE performance of as-developed catalysts could be adjusted by optimizing the molar ratio of Cu/Pt ions. Among them, the optimal Cu1Pt3/CN photocatalyst yields a higher PHE performance (672.85 mu mol g-1 h-1). Notably, the Cu1Pt3/CN catalyst also reveals an enhanced photocatalytic activity for H2 evolution in natural seawater. The possible PHE mechanism in CuPt/CN heterostructures is discussed toward the role of CuPt alloy deposition in boosting photocatalytic efficiency.