Magnetic Photocatalyst BiVO₄/Mn-Zn ferrite/Reduced Graphene Oxide: Synthesis Strategy and Its Highly Photocatalytic Activity.

Taiping Xie,Hui Li,Chenglun Liu,Tiancun Xiao,Longjun Xu,Jun Yang

doi:10.3390/nano8060380

Abstract

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.

Highlights

In the recent decade, composite semiconductor materials are considered extraordinarily attractive in the field of solar energy and pollution control engineering
The photocatalytic activity of BiVO4/Mn1−xZnxFe2O4/Reduced graphene oxide (RGO) was investigated by the rhodamine B (RhB) degradation under visible light irradiation [22]
Graphene oxide (GO) was dispersed in BiVO4/Mn1−xZnxFe2O4 with deionized water under room temperature, RGO was produced by NH3 H2O + N2H4 H2O reduction of GO without heating

Summary

Introduction

Composite semiconductor materials are considered extraordinarily attractive in the field of solar energy and pollution control engineering. Many kinds of photocatalytic composite materials with superior optical properties and high photo-induced activity have been synthesized and studied [1,2]. The utilization efficiency of visible light for some photocatalysts is very low, owing to their large intrinsic band gap energy, which impels scientists to explore new photocatalytic compounds with high visible light-driven photocatalytic activity. Magnetic composite photocatalysts are vitally important in photocatalysis materials science, due to their simple recovery via an external magnet after reaction. Magnetic compounds, such as Fe3O4 and ZnFe2O4, have been extensively studied, due to their interesting properties, including photoactivity and stability. The photocatalytic activity and mechanism are deeply investigated with RhB degradation and the radical capturing experiments using BiVO4/Mn1−xZnxFe2O4/RGO as photocatalyst

Experimental Procedures

Materials Characterization

Optimal Synthesis Condition

Structure and Phase Identification

Electrochemical Performance

Conclusions