Charge Transfer\nDynamics of Gamma Irradiation-Induced\nPEC Catalytic Process of BiVO<sub>4</sub>/Co–B<sub>i</sub>

Bismuth vanadate (BiVO<sub>4</sub>) is a promising electrode\nmaterial\nfor photoelectrochemical (PEC) water oxidation. However, the material\nundergoes efficiency loss due to charge recombination. In the present\nstudy, BiVO<sub>4</sub> photoelectrodes were treated with gamma irradiation\nto enhance their catalytic performance. The photoanodes were fabricated\nwith BiVO<sub>4</sub> and a cobalt borate (Co–B<sub>i</sub>) surface layer incorporated with BiVO<sub>4</sub>, over which gamma\nirradiation treatment was carried out. The radiation treatment enhanced\nthe photocurrent from 0.72 mAcm<sup>–2</sup> to 1.21 mAcm<sup>–2</sup> in the FTO/BiVO<sub>4/</sub>Co–B<sub>i</sub> sample. Electrochemical parameters were evaluated from the Mott–Schottky\nmeasurements along with the charge transfer and transport kinetics\nof the PEC process. The lifetime of charge carriers has also been\nincreased. The enhancement in the open circuit photovoltage (OCPV)\nby about 0.35 V in the FTO/BiVO<sub>4/</sub>Co–B<sub>i</sub> sample at 50 kGy radiation doses compared with that in unirradiated\nFTO/BiVO<sub>4</sub> has been correlated with the corresponding shift\nin the Fermi energy toward the conduction band, which has a positive\nimpact on the enhancement of charge transfer dynamics and thus the\ncatalytic performance.