BiVO4/CuBi2O4 heterojunction photoanodes with enhanced charge separation for efficient photoelectrochemical water splitting
Angang Song, Yuheng Zhang, Zhixue Li, Junhua Hu
Abstract
BiVO 4 /CuBi 2 O 4 photoanodes were fabricated by depositing CuBi 2 O 4 layers on top of BiVO 4 layers while employing a solution-based deposition technique. Carrier separation and transfer are facilitated by the heterojunction that forms between BiVO 4 and CuBi 2 O 4 , which significantly raises carrier density. Time-resolved photoluminescence (TRPL), UV–VIS absorption spectra, scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were employed for the characterization of the photoelectrode. The heterojunction photoelectrode demonstrated enhanced photoelectrochemical activity in comparison to BiVO 4 alone, with the maximum photocurrent density of 1.15 mA/cm 2 at 1.23 V vs. RHE. The improvement is attributed to decreased recombination of photo-generated electrons and holes and improved charge separation and transport in the heterostructure. By the generation of heterojunctions, the current work offers a new avenue for the design and construction of photoanodes with high charge separation efficiencies. This may be useful for the further enhancement of PEC water-splitting performances.