Mo-doping induced crystal orientation reconstruction and oxygen vacancy on BiVO4 homojunction for enhanced solar-driven water splitting

Abstract

• A facile CVD method was employed to introduce Mo doping on BiVO 4 photoanode. • Mo doping will induce the reconstruction of BiVO 4 surface, thereby forming a homojunction. • Oxygen vacancies will be generated by Mo doping, which is beneficial for OER reaction. • The CoPi/Graphene/Mo:BiVO 4 photoanode exhibits excellent OER activity. • This work provide a promising strategy for designing high-performance BiVO 4 photoelectrodes. Fabrication junction and doping are the two major methods to improve the charge separation and transfer efficiency of BiVO 4 (BVO) photoanode to boost its photoelectrochemical water splitting performance. Most of the reported methods require complicated fabrication steps, therefore increasing the usage of hazardous chemicals and cost as well. Herein, we report a BiVO 4 homojunction with abundant oxygen vacancies fabricated by a surface crystal orientation reconstruction induced by one step Mo doping method. After Mo doping, a few nanometer BVO with crystal orientation of (1 2 1) is formed on BVO (1 1 0) surface with abundant oxygen vacancies on BVO photoanode. Mo doped BiVO 4 photoanode (Mo:BVO) exhibits an obvious improvement of photocurrent (∼1.63 folds) compared with the pristine BVO. Using graphene as the hole extraction layer and CoPi as the cocatalysts, CoPi/Gr/Mo:BVO photoanode shows a high oxygen evolution reaction (OER) activity with the onset potential of 0.3 V vs. RHE and photocurrent of 4.36 mA cm −2 at 1.23 V vs. RHE under AM 1.5 G illumination. This work provides a promising strategy for the design of high-performance BiVO 4 photoelectrodes.