Synergistic Electric Metal (Ni SAs)‐Semiconductor (CdS NPs) Interaction for Improved H2O‐to‐H2 Conversion Performance under Simulated Sunlight

Abstract

Single‐atom (SA) cocatalysis has obvious superiority in promoting solar‐to‐chemical energy conversion. However, easy aggregation of SAs is very unfavorable to its catalysis for high surface energy. Herein, a photoreduction procedure is adopted to immobilize Ni SAs on CdS nanoparticles (NPs) to construct the synergistic electric metal–semiconductor interaction (EMSI) for highly promoting the simulated sunlight‐driven H2O‐to‐H2 (HTH) conversion in alkaline condition (pH = 14.0) without any sacrificial agent addition, and the nanocatalyst with 1.25‰ of Ni carrying capacity (CdS–Ni1.25‰) achieves the highest HTH conversion rate (8149.71 μmol h−1 g−1, 13.0‐fold greater of that of CdS NPs) and stable photostability accompanied by 27.60% of apparent quantum yield (AQY400 nm). Characterizations and density functional theory calculations indicate that the EMSI on CdS–Ni1.25‰ nanocatalyst greatly improves the light absorption capacity and promotes the orderly bulk‐to‐surface migration of photoexcitons, effectively suppressing their recombination kinetics for higher photoexciton utilization efficiency. Under alkaline conditions, high concentration of OH− ions is easy to react with photogenerated holes to generate hydroxyl radicals for effectively inhibiting the oxidation half‐reaction and obtaining higher HTH conversion performance due to significantly reduced energy barriers on atomic Ni sites. This study provides an insight for improving the performance of a conventional photocatalyst through non‐noble metallic SAs cocatalysis.