Simultaneous Modulation of Interface Reinforcement, Crystallization, Anti‐Reflection, and Carrier Transport in Sb Gradient‐Doped SnO2/Sb2S3 Heterostructure for Efficient Photoelectrochemical Cell

Abstract In this study, an effective quadruple optimization integrated synergistic strategy is designed to fabricate quality Sb gradient‐doped SnO 2 /Sb 2 S 3 heterostructure for an efficient photoelectrochemical (PEC) cell. The experimental results and theoretical calculations reveal that i) optical absorption matching is realized by combining the anti‐reflection of SnO 2 and high light absorption ability of Sb 2 S 3 in the visible region; ii) interface reinforcement is carried out by coordinating gradient‐distributed Sb in SnO 2 with S in S‐rich precursor of Sb 2 S 3 for improving the Sb 2 S 3 crystallization process and matching crystalline lattice of Sb:SnO 2 and Sb 2 S 3 ; iii) ultrahigh electron mobility is achieved by making Sb gradient‐doped SnO 2 ; iv) carrier separation and transport are accelerated by constructing type‐II heterojunction with appropriate energy level alignment and forming a high‐speed electron transport channel. All of above‐mentioned optimization effects are integrated into a synergistic strategy for constructing the Sb:SnO 2 /Sb 2 S 3 photoanode, achieving a photocurrent density of 2.30 mA cm −2 , hydrogen generation rate of 30.03 µmol cm −2 h −1 , and decent working stability. Notably, this method can also be used in other large‐scale fabrication processes, such as drop‐casting, spray‐coating, blade‐coating, printing, slot‐die, etc. Moreover, this universal integrated strategy paves an avenue to fabricate efficient photoelectrodes with excellent photoelectrochemical performances.