Intergrowth of Cocatalysts with Host Photocatalysts for Improved Solar-to-Hydrogen Conversion

In the field of photocatalytic hydrogen generation, cocatalysts play a vital role in enhanced properties. Delicate control of the physicochemical properties of cocatalysts and systematic optimization of the coupling between cocatalysts and host photocatalysts are essential. Herein, a simple one-step hydrothermal method was proposed to synthesize noble-metal-free NiS_x/CdS photocatalysts for the first time. Time-dependent growth studies revealed that NiS_x cocatalysts and CdS host photocatalysts were intergrown with each other in the one-step hydrothermal process. Compared with NiS_x@CdS photocatalysts prepared by the common two-step method, the intergrowth effect induced close contact between NiS_x and CdS, as well as smaller size and better dispersity of NiS_x nanoparticles. These specific characters of NiS_x/CdS finally resulted in efficient charge separation and rapid surface reaction, giving rise to significantly improved photocatalytic activity with the apparent quantum efficiency at 420 nm as high as 60.4%. To our knowledge, this value is the highest efficiency for NiS_x modified CdS photocatalysts and is among the best efficiencies for visible-light-driven photocatalysts. It is believed that the present work can provide a general guidance to develop an efficient heterostructured cocatalyst/photocatalyst system for hydrogen generation.