Search

Mn2O3is a conventional catalyst that is applied in photothermal catalytic oxidation of toluene while regular anions like SO42-, Cl-, and NO3-from different Mn precursors are left in Mn2O3. When applied in toluene degradation, the declining activity of Mn2O3is always observable because the residual anions block the Mn4+/Mn3+active sites, shield the oxygen vacancies, and cube the production of active oxygen species (O2-, O-). Herein, it is found that the residual SO42-, Cl-, and NO3-make Mn2O3incapacitated in deeply oxidizing the intermediates and cutting off the reaction process, and their influence ranks in the order of SO42->Cl->NO3-. Compared with pristine Mn2O3, the drops in CO2conversion efficiency account for 11 %, 60 %, and 73 %, respectively. Nevertheless, rinsing with water is an effective method to remove the residual anions, and the more the rinsing, the better the toluene mineralization degree. This work provides a profound cognition of the deactivation mechanism of SO42-, Cl-, and NO3-and points out an effective way to abate their negative effect for the first time.

Oxygen vacancy/Ti3+engineered TiO2nanotube arrays were prepared through electrochemical strategy at high potential (−6 V). The electrons surging from DC power initiate the valance decline of Ti4+, and countless H2bubbles released from TiO2surface lead to the in-situ exfoliation of some TiO2tiny debris, generating point defects containing Ti3+inside the TiO2and oxygen vacancy (OV) embedded on TiO2. The generated Ti3+/ OV help TiO2to increase the harvest toward visible light and serve as active sites for activating molecular oxygen to form superoxide radical (·O2-). Besides, as improved separation of electron-hole pairs endowed by the defects, the yield of hydroxyl radicals (·OH) is enhanced compared with the pristine TiO2. Chloramphenicol (CAP, an antibiotic) molecules can be efficiently degraded with the reduced TiO2under the visible light with its degradation and evolution pathway expounded in detail. Fukui index is employed to anticipate the probable sites that are subjected to oxidation by·OH and the MS spectra evidence that the·OH governs the decomposition routes of CAP molecules. ECOSAR simulation evaluates the toxicity of CAP and the intermediates, demonstrating that the final products from the photocatalysis do not post any hazardous risk on ecosystem.