Simultaneous Modulation of Interface Reinforcement, Crystallization, Anti-Reflection, and Carrier Transport in Sb Gradient-Doped SnO 2 /Sb 2 S 3 Heterostructure for Efficient Photoelectrochemical Cell.

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.