Fabrication of highly effective Ag6Si2O7/SmFeO3 heterojunction with synergistically enhanced sonophotocatalytic degradation of ciprofloxacin and production of H2O2: Influencing factors and degradation mechanism

The design of an effective catalyst for refractory pollutant destruction and H2O2 production remains a major challenge. In this study, a number of novel Ag6Si2O7/SmFeO3 (ASF) heterojunction catalysts were rationally fabricated through an in-situ precipitation strategy. The properties of the fabricated ASF nanocomposites were confirmed through different characterization techniques. In particular, the ASF-1.5 sample exhibits excellent sonophotocatalytic efficiency (94.9%) in an initial ciprofloxacin (CIP) concentration of 10 mg/L, a catalyst dosage of 0.6 g/L, US power of 400 W, pH of 5.0, and US frequency of 40 kHz within 60-min irradiation. Furthermore, the optimized ASF-1.5 sample exhibited the best H2O2 production rate of 258.5 μM, which was 2.92-fold higher than that of bare Ag6Si2O7. Scavenging experiments demonstrated that •OH and h+ were the primary reactive oxidative species (ROS) in the CIP abatement reaction. The synergistic effect of ultrasound and visible light can then promote ROS production, enabling the ASF-1.5 heterojunction to exhibit superior efficiency in CIP degradation and H2O2 generation. Moreover, a tentative sonophotocatalytic mechanism and potential routes for CIP degradation were established. To summarize, this study provides new insights into the rational design of highly effective ASF sonophotocatalysts for clean energy production and ecological applications.