A novel dual chemical bath deposition and drop-casting strategy for fabricating pinhole-free CoV2O6/BiVO4 heterostructure has been developed. This dual-deposition approach was crucial for preventing pinhole formation and thereby minimizing the solution-mediated back-reduction reaction at the FTO back contact. The developed photoanodes delivered a stable photocurrent density of 4.55 mA cm−
2 at 1.23 VRHE and achieved an applied bias photon-to-current efficiency of 1.45%, representing a sevenfold improvement over pristine BiVO4.
Developing a facile approach for the fabrication of high-quality BiVO4 films is essential to enhance the photoelectrochemical performance of BiVO4 photoanodes. Herein, we report a novel dual chemical bath deposition and drop-casting strategy for fabricating pinhole-free CoV2O6/BiVO4 heterostructure. First, a Co(OH)2 layer was grown on an FTO substrate via chemical bath deposition. Then, a Bi/V precursor mixture was drop-cast and annealed to obtain high-quality CoV2O6/BiVO4 photoanodes. This dual-deposition approach was crucial for preventing pinhole formation and thereby minimizing the solution-mediated back-reduction reaction at the FTO back contact. Photoelectrochemical measurements revealed that the CoV2O6/BiVO4 photoanodes exhibited a fivefold increase in photocurrent compared to pristine BiVO4 photoanodes. After modification with water oxidation cocatalysts, the photoanodes delivered a stable photocurrent density of 4.55 mA cm−2 at 1.23 VRHE. They demonstrated a Faradaic efficiency of 95% and achieved an applied bias photon-to-current efficiency of 1.45%, representing a sevenfold improvement over pristine BiVO4. The enhanced photoelectrocatalytic performance is primarily attributed to the formation of the pinhole-free CoV2O6/BiVO4 heterostructure, which suppresses surface recombination and extends the lifetime of photogenerated holes, as confirmed by transient photocurrent and intensity-modulated photocurrent spectroscopy measurements. The developed dual-deposition strategy is facile and can be applied to other metal oxide-based photoanodes.
Solar RRL, Volume 9, Issue 19, October 2025. Read More
