Strong interfacial interaction and asymmetric crystal modification to improve the charge transfer kinetics of cascade type II-I Bi2O2S/Bi2S3/ZnIn2S4-O composite photoanode

Bismuth oxysulfide (Bi2O2S), as a unique new two-dimensional layered material, has gradually attracted the interest of researchers because of its excellent photoelectric properties. How to enhance its charge kinetics is the key to improve photoelectrochemical (PEC) properties. Herein, the cascade type II-I heterostructure of Bi2O2S/Bi2S3/ZnIn2S4O (oxygen doping) was rationally fabricated by oxygen doping for efficient PEC water splitting through one-step hydrothermal method. Bi2S3 was in close contact with Bi2O2S through Bi atom sharing, while ZnIn2S4O has enhanced polarity. The double-synergistic effect of the cascade II-I heterojunction with strong interface interaction and asymmetric crystal modification could greatly promote the transfer efficiency of the surface charge and the bulk charge, inhibited the photogenerated carrier recombination, and enhanced the overall charge dynamics. The results showed that the photocurrent density of Bi2O2S/Bi2S3/ZnIn2S4O composite photoanode was 4.82 mA cm−2 under the condition of 1.23 V vs. RHE, which was 9.09 times with that of monomer Bi2O2S. This study opened up a new way for the application of Bi2O2S-based photoelectrodes in the field of PEC water splitting.