A cobalt silicate modified BiVO4 photoanode for efficient solar water oxidation

BiVO 4 is one of the most promising photoanode materials for photoelectrochemical (PEC) water splitting, but it usually suffers from severe charge recombination. In this work, cobalt silicate (Co-Sil) was decorated on a nanoporous BiVO 4 photoanode as a novel cocatalyst by photoelectrophoretic deposition that integrated photoelectrochemical oxidation and electrophoretic deposition. The resultant BiVO 4 /Co-Sil photoanode reached a photocurrent density of 5.0 mA/cm 2 at 1.23 V RHE , around 3-fold enhancement compared with the pristine BiVO 4 photoanode. Detailed PEC measurements combined with density functional theory calculations revealed that the excellent performance of the Co-Sil cocatalyst could be attributed to the electron transfer from Co-Sil to BiVO 4 , the reduced overpotential of the OOH* formation, and the photoelectrochemical oxidation of Co(II). Furthermore, a high photostability was achieved for the BiVO 4 /Co-Sil photoanode by dissolving NaVO 3 in the electrolyte. This work may provide new insights on the rational design and effective fabrication of promising cocatalysts for solar water splitting.