New application of resin macrospheres: preparation of Bi2O3/C photocatalysts from an inexpensive organic carbon source and their application in dye wastewater treatment

Abstract

Using macroporous ion exchange resin macrosphere D113 as an inexpensive organic carbon source, a composite precursor was constructed with Bi(OH)₃ using a hydrothermal method. A series of new bismuth-based composite photocatalytic materials, Bi₂O₃/C, were prepared using pyrolysis technology and it was shown that the bismuth element existed in the form of Bi₂O₃ in the composite. It was uniformly distributed on the surface of a graphitized carbon macrosphere and exhibited a high electron transfer rate. The UV-vis diffuse reflectance spectrum and photoluminescence verified that Bi₂O₃/C exhibited a good light absorption performance and a low photogenerated electron hole recombination rate due to the optimized band structure. Electrochemical tests such as an i–t curve and electrochemical impedance spectroscopy showed that Bi₂O₃/C-500 had a good photoelectric response. In combination with the Tauc curve, the band structure of Bi₂O₃/C-500 was verified. Bi₂O₃/C-500 could degrade methylene blue (20 mg L⁻¹) completely in 120 min, and the degradation rate remained at 90.30% for three photocatalytic cycles. The preparation method of the new Bi₂O₃/C was simple, inexpensive, and convenient for the commercial application of dye wastewater.