有机酸刻蚀钙钛矿催化甲烷燃烧性能

The main component of natural gas was methane, which escaped during its use, causing serious harm to the environment. Catalytic combustion was one of the most effective methods to control methane, and the development of catalysts with high performance for methane combustion was the key. This work taking LaMn_0.6Ni_0.4O₃ perovskite as the matrix, in view of the problems of low specific surface area, few exposed active sites and low redox ability of traditional perovskite, citric acid and ascorbic acid were used as acid treatment agent to etch LaMn_0.6Ni_0.4O₃ perovskite respectively, and surface modified catalysts LMN-mx (m was N or K; x=1, 3, 5 h) were prepared. The perovskite structure was retained after etching by citric acid and ascorbic acid. At the same time, the specific surface area of the catalyst increased from 17.1 m²/g to 22.0 m²/g. The acid etching was beneficial to the generation of surface oxygen vacancies and the enrichment of adsorbed oxygen, and the content of Mn⁴⁺ species on the surface of perovskite was increased. In addition, acid etching could also effectively improve the reduction ability of the catalyst. Among all the as-prepared catalysts, LMN-N3 exhibited the best catalytic activity. The temperature was 537 ℃ when the conversion of methane was 90%, which was lower than that of LMN and LMN-K3. Meanwhile, the LMN-N3 catalyst exhibited great thermal stability and water resistance. The research results indicated that using organic acid to etch perovskite could increase the amounts of active species and improve its catalytic activity. This modification strategy was simple and easy to use, it had a wide range of applications and had good application prospects.