The hydrophilic treatment of a novel co-catalyst for greatly improving the solar water splitting performance over Mo-doped bismuth vanadate.

Abstract In this work, Molybdenum (Mo) doped bismuth vanadate (BiVO4) is carried out by traditional calcination method, while carbon-based cobalt (Co-Ci) is prepared by photoelectric deposition (PED) and used as co-catalyst to decorate the surface, its photocurrent density reached 3.15 mA/cm2 at 1.23 V vs RHE. More importantly, the H-Co-Ci/Mo: BiVO4 photoanode obtained by plasma etching of Co-Ci/Mo: BiVO4 has greatly improved surface hydrophilicity. The photocurrent density of H-Co-Ci/Mo: BiVO4 photoanode is 4.8 times that of BiVO4 photoanode, reaching 3.95 mA/cm2. In addition, the incident photon-current conversion efficiency (IPCE) value of the H-Co-Ci/Mo: BiVO4 photoanode is as high as 60%, and both the injection and separation efficiency have also been enhanced. The enhanced photoelectrochemical (PEC) performance is attributed to the good wettability of the material surface and improvement of water oxidation kinetics. These findings provide a mild and efficient modification method for improving BiVO4 used for water splitting, and are expected to provide new ideas for other photoanodes.