Visible-light-responsive BiVO4/NH2-MIL-125(Ti) Z-scheme heterojunctions with enhanced photoelectrocatalytic degradation of phenol

BiVO4 is currently recognized as one of the most promising photoanodes for the remediation of organic pollutants. However, the poor charge transport ability of pure BiVO4 limits its quantum efficiency. Herein, to address this issue, a novel Z-scheme BiVO4/NH2-MIL-125(Ti) (BiVO4/NM125) heterojunction photoanode was successfully constructed through a one-step solvothermal process, and its physicochemical properties were characterized by various analytical techniques. After 150 min of irradiation, the optimum BiVO4/NM125 photoanode exhibited excellent degradation efficiency toward phenol (96.5 %) in comparison to single BiVO4 or NM125 at a bias of 2.0 V. The outstanding photoelectrocatalysis (PEC) activity was mainly owed to the promoted charge separation and migration efficiency, which was demonstrated by optical and photoelectrochemical measurements. The h+, •OH and O2•− were responsible for the degradation of both phenol and p-benzoquinone, as confirmed by radical scavenger experiments. After five cycles, the BiVO4/NM125 photoanode exhibited good stability with slight activity attenuation. The Z-scheme charge transfer mechanism was favorable for enhancing PEC activity instead of the type-Ⅱ mechanism. This work offers a new way for the construction of novel BiVO4–based Z-scheme heterojunction photoanodes for the degradation of phenol-containing wastewaters.