Resorcinol-formaldehyde resin nanoparticles as surface charge transfer and separation sites for the improvement of BiVO4 film photoanodes’ performance in solar water oxidation

The poor properties of carrier separation and transfer on BiVO 4 surface are two major bottlenecks for nanostructured BiVO 4 photoanodes during solar water oxidation. Herein, BiVO 4 /resorcinol–formaldehyde resin (BiVO 4 /RFS) heterojunction films were prepared by coupling resorcinol–formaldehyde resin (RFS) nanoparticles on BiVO 4 films’ surface, and investigated as photoanodes for solar water oxidation. The light harvesting and electrochemical properties of the resultant BiVO 4 /RFS film was close to the BiVO 4 film, but its carrier radiative recombination was weakened significantly. Relative to the BiVO 4 film photoanode, better water oxidation activity, kinetics and stability were observed on the BiVO 4 /RFS film photoanode. The conduction and valence band potential of RFS nanoparticles were discovered to be lower than those of BiVO 4 , and the surface photogenerated holes and electrons could be directionally transferred to RFS nanoparticles and BiVO 4 film, respectively. The higher solar water oxidation performance on the BiVO 4 /RFS photoanode was mainly originated from the separation and transfer of surface carrier through the BiVO 4 /RFS coupling interfaces under AM 1.5G irradiation. The present work could provide inspiration in the design and development of similar heterojunction materials for solar water splitting.