Hierarchical BiOHC2O4/Bi2O2CO3 composite microrods fabricated via insitu anion ion-exchange and their advanced photocatalytic performance

BiOHC2O4 microrods as the template were first synthesized via a facile microwave hydrothermal method. Then, BiOHC2O4/Bi2O2CO3 microrods and Bi2O2CO3 nanosheets with hierarchical structure were in-situ synthesized at room temperature by carbonate ion-exchange using BiOHC2O4 crystals as a template. The obtained hierarchical BiOHC2O4/Bi2O2CO3 microrods and Bi2O2CO3 nanosheets displayed superior texture properties in aqueous photocatalytic reactions, e.g. low density, large specific surface area and good dispersion. Therefore, these hierarchical BiOHC2O4/Bi2O2CO3 microrods possessed excellent photocatalytic activity for azo dye methyl orange (MO) degradation. The reason for the high photocatalytic performance of BiOHC2O4/Bi2O2CO3 microrods could be due to their unique interface which endows with efficient light harvesting capability and high carrier separation and utilization. Radical capture test confirmed that more h+ and ·O2− were produced over this unique hierarchical BiOHC2O4/Bi2O2CO3 heterojunction. A possible reaction pathway involved two-electrons reduction of oxygen for promoting photocatalytic degradation efficiency of MO was proposed.