Defects and plasma Ag co-modified S-scheme Ag/NVs-CN/Bi2O2-δCO3 heterojunction with multilevel charge transfer channels for boosting full-spectrum-driven degradation of antibiotics

Abstract

The optimization of the photogenerated carriers’ relaxation dynamics process is critical for the improvement of photocatalytic performance. Herein, a ternary heterojunction with multilevel charge transfer channels was constructed by coupling plasma Ag, nitrogen vacancies carbon nitride (NVs-CN) and Bi2O2-δCO3. Ag/NVs-CN/Bi2O2-δCO3 heterojunction showed the S-scheme mechanism, which not only promoted the interfacial charge transfer, but also enhanced the driving force for redox reactions. The defect states induced by nitrogen vacancies and oxygen vacancies provided an additional energy level platforms for hot electrons relaxation of plasma Ag, resulting in the improved separation efficiency and utilization rate of the high-energy hot carriers. Hence, the prepared Ag/NVs-CN/Bi2-δO2CO3 heterojunction exhibited the markedly boosted full-spectrum driven catalytic activity for antibiotics degradation. 80.5% and 83.8% of tetracycline and ciprofloxacin could be mineralized into H2O and CO2 by the optimal heterojunction under visible light irradiation, and the corresponding mineralization efficiencies could reach 81.7% and 81.5% under NIR light irradiation. The proposed multichannel charge transfer mechanism provided a new insight into the design and preparation of high-active full-spectrum responsive heterojunction photocatalysts.