Orientation-engineered epitaxial BiVO4 thin films for efficient photoelectrochemical glycerol valorization

Abstract

Epitaxial BiVO4 photoanodes with precisely controlled crystallographic orientations were fabricated to elucidate the intrinsic influence of facet anisotropy on photoelectrochemical (PEC) glycerol oxidation. The b-axis-oriented (0k0) BiVO4 film exhibited a 2.4-fold higher photocurrent density and a 2.6-fold greater charge-separation efficiency than the c-axis-oriented (00l) film, achieving a production rate of 81.4 mmol m−2 h−1 under AM 1.5 G illumination. PEC and charge-transfer analyses reveal that the enhanced activity of the (0k0) facet originates primarily from improved bulk charge separation and transport rather than surface catalytic effects. This work establishes crystallographic orientation control as an effective design strategy for developing energy-efficient oxide photoanodes for solar-driven glycerol oxidation beyond conventional water splitting.