Construction Of Dual Z-scheme CuO/CuBi₂O₄/Bi₂O₃ Composite Photocatalyst And Study On Photocatalytic Activity

With the rapid growth of population and the development of modern industry,a series of environmental pollution has become the key problem for the development of the whole society.A large number of industrial and domestic wastewater and medical antibiotic wastewater are released into the environment,which has a significant impact on human and animal health and the sustainable development of the environment.Traditional wastewater treatment methods,such as physical treatment,biological treatment,and chemical treatment,often have the problems of high treatment cost,complex operation,and secondary pollution to the environment after treatment.In recent years,photocatalytic oxidation technology has developed rapidly because of its high reaction activity,high treatment efficiency,low cost,and complete mineralization of target pollutants.At present,to overcome the shortcomings of traditional single semiconductor photocatalyst light response to a narrow range and light carrier recombination rate is high,many researchers have constructed binary Z-scheme photocatalyst to improve the separation efficiency of photogenerated carriers.However,there is usually an obvious interface between the two semiconductors of many binary Z-scheme photocatalysts prepared,which is not conducive to the transmission of photogenerated electrons.In addition,there is single oxidation or reduction surface in the binary Z-scheme system,which limits the further improvement of the redox ability of the system.In order to solve these problems,constructing a ternary dual Z-scheme composite photocatalytic system with high electron transfer efficiency and multiple oxidation or reduction surfaces is an ideal way to improve photocatalytic activity.In this study,a dual Z-scheme CuO/CuBi₂O₄/Bi₂O₃composite photocatalyst was constructed based on the incomplete solid-phase chemical reactions of hydroxide,and a series of characterization analyses were carried out.Taking Norfloxacin（NFX）as the target pollutant,some factors affecting the activity of the CuO/CuBi₂O₄/Bi₂O₃composite photocatalytic system were investigated under simulated solar light,and the optimal conditions for NFX degradation were sought.The possible mechanism of photocatalytic degradation of organic pollutants using dual Z-scheme CuO/CuBi₂O₄/Bi₂O₃nanocomposite photocatalytic system was proposed.The results show that the dual Z-scheme CuO/CuBi₂O₄/Bi₂O₃composite photocatalyst successfully constructed in this study can effectively utilize solar light.Compared with pure CuO,Bi₂O₃,and CuBi₂O₄,the dual Z-scheme CuO/CuBi₂O₄/Bi₂O₃composite photocatalyst has a higher degradation extent of NFX and higher separation efficiency of photogenerated electron-hole pairs.At 1.0 g/L dosage of CuO/CuBi₂O₄/Bi₂O₃,the degradation extent of NFX（5.0 mg/L）reaches 82.4%within240 min.Besides,the dual Z-scheme CuO/CuBi₂O₄/Bi₂O₃has a high degradation ability for NFX after four cycles.In addition to NFX,the dual Z-scheme CuO/CuBi₂O₄/Bi₂O₃composite photocatalyst can degrade other antibiotics and dyes such as acridine orange,methylene blue,crystal violet,and tetracycline under solar light.The production of active radicals such as h⁺,·OH,and·O₂^-are confirmed through the free radical capture experiment,and h⁺plays a major role in the degradation of NFX.The above results show that the dual Z-scheme CuO/CuBi₂O₄/Bi₂O₃composite photocatalyst constructed based on the incomplete solid-phase chemical reactions of hydroxide has strong photocatalytic activity.This technology has broad application prospects in the preparation of novel multiple photocatalysts and the treatment of organic wastewater by solar light.