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

In this work, Molybdenum (Mo) doped bismuth vanadate (BiVO 4 ) 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/cm 2 at 1.23 V vs RHE. More importantly, the H-Co-Ci/Mo: BiVO 4 photoanode obtained by plasma etching of Co-Ci/Mo: BiVO 4 has greatly improved surface hydrophilicity. The photocurrent density of H-Co-Ci/Mo: BiVO 4 photoanode is 4.8 times that of BiVO 4 photoanode, reaching 3.95 mA/cm 2 . In addition, the incident photon-current conversion efficiency (IPCE) value of the H-Co-Ci/Mo: BiVO 4 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 BiVO 4 used for water splitting, and are expected to provide new ideas for other photoanodes.