Magnetic photocatalyst BiVO₄/Mn-Zn ferrite (Mn1-xZnxFe₂O₄)/reduced graphene oxide (RGO) was synthesized by a simple calcination and reduction method. The magnetic photocatalyst held high visible light-absorption ability with low band gap energy and wide absorption wavelength range. Electrochemical impedance spectroscopies illustrated good electrical conductivity which indicated low charge-transfer resistance due to incorporation of Mn1-xZnxFe₂O₄ and RGO. The test of photocatalytic activity showed that the degradation ratio of rhodamine B (RhB) reached 96.0% under visible light irradiation after only 1.5 h reaction. The photocatalytic mechanism for the prepared photocatalyst was explained in detail. Here, the incorporation of RGO enhanced the specific surface area compared with BiVO4/Mn1-xZnxFe₂O₄.The larger specific surface area provided more active surface sites, more free space to improve the mobility of photo-induced electrons, and further facilitated the effective migration of charge carriers, leading to the remarkable improvement of photocatalytic performance. Meanwhile, RGO was the effective acceptor as well as transporter of photo-generated electron hole pairs. •O₂- was the most active species in the photocatalytic reaction. BiVO₄/Mn1-xZnxFe₂O₄/RGO had quite a wide application in organic contaminants removal or environmental pollution control.
Keywords: BiVO4; Mn–Zn ferrite; RGO; magnetic performance; magnetic photocatalyst; photocatalytic mechanism.