Room chemical bath temperature deposition of Mn:FeOOH on BiVO4 photoanode to enhance water oxidation

BiVO4 is one of the substrates that have received wide attention from researchers for photoelectrochemical (PEC) water oxidation due to its narrow band gap and sufficiently upbeat valence band. In this study, Mn-FeOOH cocatalyst was synthesized on the BiVO4 photoanode by a chemical bath deposition method at room temperature. As water oxidation cocatalyst, FeOOH could oxidize H2O to O2 kinetically easier. Furthermore, the Mn element mixing increases the active sites, leading to a faster charge transfer rate by decreasing the kinetics barrier, and it can act as a passivation layer to suppress electron-hole recombination. The results show that the photocurrent density of Mn-FeOOH/BiVO4 is 1.4 mA cm-2 (1.23 VRHE), which is 2.3 folds that of the bare BiVO4 electrode (0.6 mA cm-2), and the onset potential is also negatively shifted by 130 mV and provides a new idea for the design of photoelectrodes.