Sufficient energy band utilization profited from spatially discrete heterogeneous interfaces to induce efficient photoelectrochemical water splitting for ZnIn2S4 photoanode

The applied possibility of ZnIn2S4 is improved in the photoelectrochemical (PEC) energy transfer filed through elevated light absorption, accelerating charges transfer and suppressed carrier recombination. Consequently, Sb2S3/ZnIn2S4/Cu2S ternary composite photoanode is obtained through the induction of Sb2S3/ZnIn2S4 and ZnIn2S4/Cu2S heterogeneous interfaces at different spatial locations in ZnIn2S4, which enhances photocurrent density of ZnIn2S4-based photoanode to 2.81 mA/cm2 from 0.15 mA/cm2 with the nearly full visible spectrum absorption range of ∼ 776 nm. The deposition of Sb2S3 leads to enhanced quantum efficiencies, carrier diffusion time, and number of surface states. The loading of Cu2S top layer predominantly results in optimized surface states style and holes injection efficiency of SS/ZIS/CS. The comprehensive measurements and density functional theory (DFT) calculation demonstrate Sb2S3 and Cu2S are together employed to enhance the hybridization efficiencies of energy bands, accelerate charge transfer, revise the reaction sites, reduce free energy barrier of rate-determining steps and reaction over potential of ZnIn2S4 to enhance PEC water spitting. This work pioneers the construction of ZnIn2S4-based multijunction photoanodes with sufficient energy band utilization and confirms the conspicuous prospect for remaining photoanodes.