Defect Anchoring [S–Ni–P] Interfacial Channel Regulating Charge Migration for Efficient Photoelectrochemical Water Splitting

Abstract

Regulating bulk charge carrier transfer and surface catalytic reaction kinetics is thought a big challenge to photoelectrochemical (PEC) water splitting. Herein, the dual sites of CoNiP are delicately introduced into ZnIn₂S₄ (RZIS‐CoNiP) nanosheet arrays via a defect anchoring method. The paving [S─Ni─P] interfacial bond like a “bridge” can greatly reduce the phase resistance, improve the charge separation and migration, and promote the surface oxygen evolution reaction (OER) reaction. As expected, the optimized RZIS‐CoNiP photoanode achieved a maximum photocurrent density of 4.77 mA cm⁻² at 1.23 V versus reversible hydrogen electrode (RHE) in neutral electrolyte solution without the presence of any sacrificial agents, which is ≈12 times higher than that of the pristine ZnIn₂S₄ under AM 1.5G illumination. And the amount of oxygen evolution for the RZIS‐CoNiP photoanode is as high as 21.9 µmol in 3 h. Transient spectroscopy measurements and density functional theory (DFT) calculations in situ discovered the mechanism of defect anchoring [S─Ni─P] bond on regulating charge transfer and surface reaction processes. This work provides a feasible anchoring interface route through defect engineering to regulate charge carrier transfer for PEC water splitting.