Charge Transfer Dynamics of Gamma Irradiation-Induced PEC Catalytic Process of BiVO₄/Co–B_i

Bismuth vanadate (BiVO4) is a promising electrode material for photoelectrochemical (PEC) water oxidation. However, the material undergoes efficiency loss due to charge recombination. In the present study, BiVO4 photoelectrodes were treated with gamma irradiation to enhance their catalytic performance. The photoanodes were fabricated with BiVO4 and a cobalt borate (Co–Bi) surface layer incorporated with BiVO4, over which gamma irradiation treatment was carried out. The radiation treatment enhanced the photocurrent from 0.72 mAcm–2 to 1.21 mAcm–2 in the FTO/BiVO4/Co–Bi sample. Electrochemical parameters were evaluated from the Mott–Schottky measurements along with the charge transfer and transport kinetics of the PEC process. The lifetime of charge carriers has also been increased. The enhancement in the open circuit photovoltage (OCPV) by about 0.35 V in the FTO/BiVO4/Co–Bi sample at 50 kGy radiation doses compared with that in unirradiated FTO/BiVO4 has been correlated with the corresponding shift in the Fermi energy toward the conduction band, which has a positive impact on the enhancement of charge transfer dynamics and thus the catalytic performance.