Development of Bi2O2CO3/Ag2WO4 heterojunction photocatalysts incorporating oxygen vacancies for improving synergistic treatment of pollutants via adsorption and photocatalysis

Novel flower-like Bi 2 O 2 CO 3 /Ag 2 WO 4 photocatalysts incorporating oxygen vacancies were successfully prepared by chemical precipitation method. A range of characterization techniques were employed to investigate the morphology features, structure characteristics and photocatalytic properties of the photocatalysts. The composite photocatalyst extends the absorbance edge to the visible region. And it has remarkable adsorption and photocatalytic properties. It efficiently degrades almost all methylene blue (MB) within 90 min under visible light irradiation. This degradation rate surpasses that of pure Bi 2 O 2 CO 3 by a factor of 5.2. The synergistic interaction between oxygen vacancies and heterojunctions effectively diminishes the excitation energy required for the composites, while simultaneously achieving a superior separation efficiency of photogenerated electrons and holes, thereby enhancing the photocatalytic performance. Additionally, the composite photocatalysts demonstrate excellent stability and recyclability, making them suitable for practical wastewater purification. Free radical trapping experiments showed that the primary reactive substances involved in MB degradation is positive hole (h + ). Based on the experimental findings, a plausible working mechanism for Bi 2 O 2 CO 3 /Ag 2 WO 4 heterojunction composite photocatalysts incorporating oxygen vacancies, belonging to the type II heterojunction system, was proposed. This study provides novel perspectives on the development of efficient bismuth-based photocatalysts harnessing the synergistic oxygen vacancies and heterojunctions. These photocatalysts demonstrate promising application prospects in the realm of environmental remediation.