Z-Scheme Transfer Path of Charges in the BiVO4/Bi:ZnIn2S4-Co Photoanode for Photoelectrochemical Water Splitting

Abstract

The significant carrier recombination occurring in the bulk of BiVO₄ is a primary factor limiting the enhancement of its photoelectrochemical performance. To address this issue, we have incorporated two-dimensional (2D) nanosheet morphology Bi:ZnIn₂S₄ and Co sites onto the surface of BiVO₄ to create an effective composite photoanode. According to the ultraviolet-visible diffuse reflectance spectroscopy and ultraviolet photoelectron spectroscopy results, it was inferred that a Z-scheme transfer path of charges was formed between BiVO₄ and Bi:ZnIn₂S₄, which promoted the separation of bulk phase carriers. Additionally, the 2D topography of Bi:ZnIn₂S₄ also shortens the transmission distance of the carriers. Furthermore, the presence of Co sites provides more active sites for the surface hydrolysis reaction to proceed. Ultimately, under AM1.5G illumination, the photocurrent density of the BiVO₄/Bi:ZnIn₂S₄-Co photoanode reaches 3.6 mA cm^–2 at 1.23 V vs reversible hydrogen electrodes.