Preparation of N,Ni co-doped ZnIn₂S₄ for Simultaneously Trapping Electron and Hole: Insight on Photocatalytic H₂...

ZnIn₂S₄ (ZIS) have presented the great potentials in photocatalytic H₂ evolution coupled with benzyl alcohols oxidative dehydrogenation, and element doping is a feasible strategy for enhanced photocatalytic performance. Herein, N and Ni atoms co-doped ZnIn₂S₄ (N₄,Ni₂-ZIS) are prepared via partially replacing S and Zn atoms, and the optimized configuration is simulated. N and Ni atoms are respectively function as electron and hole traps, leading to the increased separation efficiency of photoinduced charge carriers, tailored band structure, and optimized surface affinity. In photocatalytic reaction, N₄,Ni₂-ZIS exhibited 58.2 mmol·g^-1·h^-1 of H₂ evolution rate and 247.0 µmol of benzaldehyde (BAD) yield, much higher than the reference ZIS (3.7 mmol·g^-1·h^-1 and 39.5 µmol). Mechanism studies indicated S atoms nearby the doped N atoms are the main sites for H₂ evolution on conduction band, and ΔG_H* is lowered from 2.06 eV (ZIS) to 1.24 eV (N₄,Ni₂-ZIS). Meanwhile, carbon-centered radicals and oxygen-centered radicals are responsible for BAD production on valence band simultaneously.This work has established a highly efficient photoredox system for green energy generation and synchronous production of high-value-added products, offering an innovative design for achieving carbon-neutrality.