Simultaneous Ni nanoparticles decoration and Ni doping of CdS nanorods for synergistically promoting photocatalytic H₂ evolution

Heteroatom doping and loading of co-catalysts are two efficient tactics to boost the photocatalytic activity of semiconductors. Combining these two strategies in one photocatalyst system has great potential to further enhance the catalytic performance. Herein, a facile and controllable atomic layer deposition (ALD)-reduction approach is used to simultaneously introduce Ni doping and Ni nanoparticles (NPs) with tunable size on CdS nanorods for boosting its photocatalytic activity. The Ni doping and Ni NPs synergistically enhance the H₂ production of CdS nanorods (NRs), achieving an optimized rate of 20.6 mmol·g⁻¹·h⁻¹ ~1.3- and 28.6-fold higher than CdS NRs supported Ni NPs with similar size and pristine CdS NRs, respectively. The Ni NPs/Ni doped CdS NRs exhibits an apparent quantum efficiency (AQE) of 37.5% at 420 nm, outperforming most previously reported Ni doped and Ni NPs decorated CdS catalysts. The outstanding photocatalytic activity of the Ni NPs/Ni doped CdS NRs can be ascribed to synergism of the Ni doping and uniformly dispersed Ni co-catalyst with appropriate size, which promote carrier separation of semiconductor and surface hydrogen evolution kinetics on nanocatalyst surface. This work provides a promising pathway to integrate heteroatom doping and loading of co-catalysts strategies in one photocatalyst system for synergistically promoting photocatalytic performance.