Epitaxial grown [hk1] oriented 2D/1D Bi₂O₂S/Sb₂S₃ heterostructure with significantly enhanced photoelectrochemical...

Bismuth oxysulfide (Bi₂O₂S) is a layered material with high carrier mobility, excellent light absorption characteristic and good stability. However, there are few reports about the use of Bi₂O₂S in photoelectrochemical (PEC) water splitting. In this paper, Bi₂O₂S nanosheets (NSs) films were prepared on FTO substrates by one-step hydrothermal method, which broke the traditional powder state of Bi₂O₂S prepared. Based on the high lattice matching between antimony sulfide (Sb₂S₃) and bismuth sulfide (Bi₂S₃) obtained from the topological transformation of partial Bi₂O₂S, Sb₂S₃ nanorods (NRs) with [hk1] predominant orientation were epitaxially grown on the surface of Bi₂O₂S to establish a transport channel for rapid carrier migration. Titanium dioxide (TiO₂) electron transport layer with oxygen vacancies was introduced into the back to capture and release electrons, further reducing the recombination rate. The photocurrent density of TiO₂/Bi₂O₂S/Sb₂S₃-annealed photoelectrode at 1.23 V vs. RHE was 4.37 mA/cm², which was 13.7 times that of monomer Bi₂O₂S. In addition, the TiO₂/Bi₂O₂S/Sb₂S₃-annealed photoelectrode had lower charge transfer resistance and the IPCE value up to 48.22%. This study is of great significance for the application of Bi₂O₂S based photoelectrodes in the field of PEC water splitting.