Trace cobalt-regulated FeP/Znln(2)S(4) Schottky heterojunction with dual electron transfer bridge boosting light-to‑hydrogen conversion.

Efficient interfacial charge transfer and robust interface interactions are critical for superior charge carrier separation and advanced heterogeneous photocatalysts. Herein, a Schottky heterojunction has been designed by in situ growth of ZnInS (ZIS) nanosheets onto Co-doped FeP nanorods (Co-FePZ), building a dual electron transfer bridge (Fe-S/Zn-P). X-ray photoelectron spectroscopy, X-ray absorption fine structure, and density functional theory calculations prove that trace Co doping alters the chemical bonding structure and Fermi level (E) of FeP and ZIS, creating a Schottky heterojunction. The reversed internal electric field and dual electron transfer pathways provide driving force and transmission channels for electron flow. Schottky heterojunction prevents electron reflux and improves carrier separation efficiency, boosting photocatalytic hydrogen evolution. The optimized Co-FePZ achieves a remarkable H production rate of 9.9 ± 0.1 mmol·g·h, approximately 12.4 times that of pure ZIS, with an apparent quantum yield (AQY) of 11 ± 1 % at 365 nm. This work delicately modulated the heterojunction interface and achieved the transition from an Ohmic heterojunction to a Schottky heterojunction, unveiling a novel strategy to optimize carrier migration pathways via trace element doping and covalent coupling.