Architecting multi-active center on 3DOM La0.76Ce0.19Ag0.05Mn0.9Co0.1O3-δ perovskite for soot oxidation

Abstract

Precise construction of multiple active centers on perovskite oxides is recognized as a feasible and promising strategy to cooperatively promote the catalytic performances. Herein, 3DOM La0.76Ce0.19Ag0.05Mn0.9Co0.1O3-δ perovskite was designed and further treated within H2/N2 flow. High-temperature reduction did not destroy the original structure of perovskite, while the lattice Ag and Co were exsolved on perovskite surfaces to form Ag/Ag2O and Co@Co3O4. Compared with the traditional impregnation method, this strategy provided the active nanoparticles with smaller size, higher dispersion, and stronger interaction with perovskite matrix. XPS and O2-TPD indicated that the exsolved Ag and Co components could not only act as the O2 activation sites to accelerate the generation of active oxygen species on surfaces, but also offered the electrons to the oxygen vacancy on the perovskite. In addition, the vacancy formed after A-site and B-site cations exsolution could also adsorb and activate O2, ultimately boosting the catalytic combustion of soot. As a result, the developed perovskite exhibited a competitive catalytic activity with the T50 of 364 ℃ under the condition of 500 ppm NO + 5 % O2/N2. This work offered a facile and effective pathway to assemble high-performance perovskite-type oxides for heterogeneous catalysis.