Synthesis of strongly interactive FeWO4/BiOCl heterostructures for efficient photoreduction of CO2 and piezo-photodegradation of bisphenol A

Development of multi-functional photocatalysts for CO2 reduction and pollutant elimination is practically significant for solving the environmental problems and energy shortages. In this study, we have immobilized FeWO4 (FWO) nanoparticles on the surface of (0 0 1)-facet-exposed BiOCl (BOC) nanosheets through their strong electrostatic interaction to form FWO/BOC heterojunctions. Experimental and theoretical studies corroborate that the FWO/BOC heterojunctions exhibit high-efficiency Z-scheme transfer and separation of photocarriers, and possess excellent photocatalysis for CO2 reduction and bisphenol A (BPA) degradation. Under simulated-sunlight irradiation, the 9 %FWO/BOC heterojunction exhibits a photoreduction performance with CH4/CO yield rates of 4.25/9.41 μmol g−1 h−1 (5 h reaction), which are 3.86/5.26 times higher than those for bare BOC; whereas its photodegradation performance (η(60 min) = 66.8 %, kapp = 0.01755 min−1) is enhanced by 4.3 and 2.7 times compared with that of bare FWO and BOC, respectively. Furthermore, when ultrasonic vibration is simultaneously employed during the simulated-sunlight illumination, the ultrasonic-induced piezoelectric polarization field in BOC nanosheets accelerates the bulk photocarrier separation, resulting in a further improvement in the BPA degradation, and the calculated SF = 1.79 quantifies the degree of enhancement achieved by piezo-photocatalysis collaboration. The introduction of a moderate amount of H2O2 or peroxymonosulfate (PMS) in the reaction solution plays a significant role in promoting the BPA degradation due to the generation of additional •OH and •SO4− reactive species. The mechanisms for photocatalytic CO2 reduction and piezo-photodegradation of BPA catalysis were deeply studied by combining experiments and theory.