In this study, an effective quadruple optimization integrated synergistic strategy is designed to fabricate quality Sb gradient-doped SnO2 /Sb2 S3 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 SnO2 and high light absorption ability of Sb2 S3 in the visible region; ii) interface reinforcement is carried out by coordinating gradient-distributed Sb in SnO2 with S in S-rich precursor of Sb2 S3 for improving the Sb2 S3 crystallization process and matching crystalline lattice of Sb:SnO2 and Sb2 S3 ; iii) ultrahigh electron mobility is achieved by making Sb gradient-doped SnO2 ; 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:SnO2 /Sb2 S3 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.
Keywords: gradient doping; heterostructures; integrated synergistic strategy; photoelectrochemical cells; quadruple optimization.
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