Facile fabrication of heterostructured BiPS4-Bi2S3-BiVO4 photoanode for enhanced stability and photoelectrochemical water splitting performance

Bismuth vanadate (BiVO4) is the most favorable electrode candidate for photoelectrochemical (PEC) water-splitting reactions. The poor charge separation and sluggish water oxidation dynamics are, however, the major setbacks of BiVO4 photoanodes. To address these issues, we demonstrate that bismuth thiophosphate (BiPS4)-Bi2S3 hybrid nanostructure was photoelectrochemically transformed on BiVO4 electrodes (BiPS4-Bi2S3-Bi2O3) when treated in Na2S/PBS electrolyte, and a notable photocurrent of 3.5 mA/cm2 at 0.65 VRHE was obtained showing promising stability. X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) examination evidenced the effective makeover of BiVO4 into the BiPS4-Bi2S3/BiVO4 nanostructured matrix. A negatively shifted onset potential and enriched durability are achieved for heterostructured BiPS4-Bi2S3/BiVO4 photoanodes due to decreased surface recombination. Interestingly, the Bode phase analysis evidenced the faster hole consumption in the water oxidation process in the BiPS4-Bi2S3/BiVO4 electrode compared to pristine BiVO4. This methodology can be engaged to design different complex nanostructured materials with tunable optical and electrical features for photoelectrocatalysis, electrical energy storage, and solar cell uses.