Synthesis of PbxCu1−xBi2O4 composites with enhanced visible-light-responsive photocatalytic degradation performance

Abstract

The unintentional release of highly toxic dyes from various industrial sectors into aquatic environments caused an imminent threat to the aquatic ecosystem and human health. Therefore, it is highly imperative to develop efficient and sustainable treatment technologies. In this work, we have constructed a novel PbxCu1−xBi2O4 nanostructured composite through a facile hydrothermal method. The atomic ratio of Pb to Cu was systematically investigated. The optimized sample of Pb0.10Cu0.90Bi2O4 has a higher visible light responsiveness for the degradation of Congo red (CR) dye than that of CuBi2O4. The results show that CuBi2O4 has the least degradation potential for CR under optimal conditions (catalyst = 0.4 g/L, [CR] = 30 mg/L, pH = 5.0, T = 25 ± 2 °C), and 83.39% degradation was achieved in 80 min under visible light irradiation. Meanwhile, Pb0.10Cu0.90Bi2O4 photocatalyst has shown 99.23% degradation of CR dye. This enhancement in the degradation of CR was considered due to the increase in the surface area of Pb0.10Cu0.90Bi2O4 (67.32 m2/g) and exposed active sites compared with that of pure CuBi2O4 (49.73 m2/g). The insertion of Pb metal ions into basic framework of the CuBi2O4 leads to increase in the specific surface area of the material, resulting in enhanced degradation. Furthermore, the insertion of Pb metal ions also lowered the optical bandgap energy of the catalytic material, which enhanced the degrading potential of Pb0.10Cu0.90Bi2O4. The effect factors were further examined, including catalyst dosage, initial dye concentration, pH, temperature, and agitation rate. In addition, the effect of humic acid and interfering anions on CR degradation was also investigated. The results of these experiments show that these factors also influence the photocatalytic degradation of CR dye. Therefore, appropriate treatment of these factors would increase the wastewater treatment efficiency by the as-prepared Pb0.10Cu0.90Bi2O4 photocatalyst.