CeO2 supported MOFs derived LaBxFeyO3 (B=Mn, Co) perovskite catalysts for degradation of toluene.

In this work, LaCoO3 and LaMnO3 perovskites with the higher specific surface area were synthesized using MOFs as precursor, then, the composite catalysts CeO2-LaCoxFeyO3 and CeO2-LaMnxFeyO3 were prepared by using CeO2 as support and Fe element doping LaCoO3 and LaMnO3, respectively. The as-prepared samples were characterized by XRD, SEM, XPS, H2-TPR, and N2 physisorption techniques. Subsequently, toluene was used as the probe molecule for volatile organic compounds (VOCs) to test the catalytic activity of these as-prepared catalysts. The results show that the initial reaction temperature for toluene oxidation on supported perovskite catalysts is lower. Among which, CeO2-LaCo0.25Fe0.75O3 (T90=215 °C, T90: the temperature corresponding to 90% conversion of toluene) and CeO2-LaMn0.25Fe0.75O3 (T90=205 °C) catalysts show the best catalytic performance. Therefore, the supported perovskite prepared in this study has the advantages of high specific surface area, abundant oxygen vacancies, and excellent oxygen mobility, which makes it exhibit better performance in VOCs catalytic oxidation.

Effect of A, B-site cation on the catalytic activity of La1-xAxMn1-yByO3 (A = Ce, B = Ni) perovskite-type oxides for toluene oxidation.

ABO3-type perovskites (A = La, Ce; B = Mn, Ni) were prepared by sol-gel method, and applied for catalytic oxidation of toluene. The activity test results show that the activity of LaMnO3 can be improved when a small amount of Ce and Ni are doped into the A and B sites of LaMnO3, respectively. The effects of different calcination temperatures and different calcination time on the preparation of La-based perovskites were also investigated. The results illustrate that the toluene conversion of La0.8Ce0.2Mn0.8Ni0.2O3 is the highest when the calcination temperature is 700 °C and the calcination time is 4 h in La1-xCexMn1-yNiyO3 perovskites, and it requires lower reaction temperature when the conversion rate of toluene reaches 100% as compared to other catalysts, the T90 is 295 °C (T90, the temperature corresponding to the 90% of toluene conversion). Importantly, the mechanism of catalytic oxidation was also discussed. Therefore, the catalyst has potential prospects in the volatile organic compounds (VOCs) degradation.