Boosting charge separation and transfer at the boron-triggered BiVO4 interface for efficient and stable solar water splitting

•Interface-confined surface engineering via NaBH4 etching toward efficent solar water splitting.•NaBH4 etching at the semicoductor/OEC interface modulates the charge carrier pathway.•Synergy effect of NaBH4 treatment and NiFeBi OEC extends charge carrier lifetime and reduces electron-hole recombination on semiconductors.•A photocurrent density of 6.33 mA cm−2 at 1.23 VRHE with a high STH efficiency of 2.3% on NiFeBi/R-BiVO4.•A feasible and versatile approach addresses the bottle-necks of PEC water splitting activity and stability.