The effect of A-site substitution by Sr, Mg and Ce on the catalytic performance of LaMnO3 catalysts for the oxidation of vinyl chloride emission

Catalytic oxidation of vinyl chloride (VC) emission was carried out over LaMnO3 and La0.8A0.2MnO3 (A = Sr, Mg and Ce) perovskite oxides synthesized via co-precipitation method. Numerous characterization techniques were performed to investigate the relationship between the catalytic performance and its physicochemical properties. It was found that the partial substitution of lanthanum by cerium and magnesium had a positive effect on the catalytic performance for VC oxidation, whereas strontium involved a negative effect. Under the reaction conditions (VC concentration = 1000 ppm, GHSV = 15,000 h−1), the overall catalyst ranking in terms of the catalytic activity from the best to the worst performance was La0.8Ce0.2MnO3 > La0.8Mg0.2MnO3 > LaMnO3 > La0.8Sr0.2MnO3 with regard to the temperature of T50 and T90. The Ce-doped perovskite catalyst showed the optimum catalytic performance due to its higher specific surface area and its ability to promote the low-temperature reducibility. Moreover, as the active species, the increased surface adsorbed oxygen was also responsible for the enhancement of the catalytic performance.

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► LaMnO3 and La0.8A0.2MnO3 (A = Sr, Mg and Ce) were prepared by co-precipitation method.
► The A-site substitution modified the amounts of Mn4+ and adsorbed oxygen on the surface.
► No by-products were formed but only CO2, H2O and HCl.
► La0.8Ce0.2MnO3 presented the best catalytic performance for vinyl chloride abatement.
► Reducibility and surface adsorbed oxygen were the main parameters.