Enhanced visible light photocatalytic activity of BiFeO3-ZnO p-n heterojunction for CO2 reduction

The visible light photocatalytic ability of bismuth ferrite-zinc oxide composites with different molar ratios was investigated for conversion of CO2 in the gas phase. The catalysts were successfully synthesized by hydrothermal method, and characterized by XRD, EDS, FESEM, UV–vis, and PL analyses. Also, the gaseous products were identified by FTIR technique. The FESEM illustrated the well crystalline particles of ZnO and BiFeO3. The UV–vis and PL analyses revealed that by increasing BiFeO3 content, the composites showed higher optical response in visible region and higher efficiency of charge separation, respectively. Compared with the pure ZnO and BiFeO3, which had poor performances under visible light irradiation, the as-synthesized photocatalysts showed the enhanced visible light photocatalytic activity for CO2 reduction. The highest photocatalytic conversion of CO2, 21%, was achieved by the as-synthesized photocatalyst with molar ratio of 1:1 under visible light. The enhanced visible light photocatalytic activity of BiFeO3-ZnO was assigned to the synergistic effect of p-n heterojunction and visible light sensitive property of perovskite structure of BiFeO3.