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 V_RHE 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.