Plasma Treatment Induced Oxygen Vacancies and N Doping in the BiVO<sub>4</sub> Photoanode toward Improved Charge Transfer and Facilitated Water Oxidation
Anchen Wang, Yaru Chen, Liu Xuefeng, Ru Li, Ziyi Zhang, Fuyang Zhang, Dapeng Cao, Zhiqiang Gao, Bao Xiu Mi
Abstract
BiVO 4 is a promising material candidate for photoelectrochemical (PEC) water splitting. However, the BiVO 4 photoanode commonly suffers from poor charge carrier transport and sluggish water oxidation kinetics, which limits its PEC performance. Nitrogen (N) doping has been proven as an effective approach to improve electric conductivity and accelerate the water oxidation kinetics of the BiVO 4 photoanode. Nevertheless, a simple and mild method for introducing a N dopant into BiVO 4 remains lacking. Herein, N 2 plasma treatment is employed as a post-treatment method to achieve effective N doping and induce oxygen vacancies (O V ) in BiVO 4 photoanodes. This treatment significantly improves the charge transfer and accelerates the kinetics of water oxidation. The photocurrent density of the N 2 -plasma-treated BiVO 4 photoanode reaches 1.39 mA cm –2 at 1.23 V versus the reversible hydrogen electrode (RHE), which surpasses that of pristine BiVO 4 (0.30 mA cm –2 ) by a substantial margin. This work provides a facile room-temperature N 2 plasma approach for the simultaneous introduction of N doping and O V into photoanodes, achieving enhanced charge transport and accelerated water oxidation kinetics.