Study on the purification performance of modified La–Ni based perovskite catalysts co-doped with metal K and Pr for simultaneous removing soot particles and NOx of diesel engine exhaust

Abstract

The synchronous removal of soot particles and NOx using high-performance catalysts is a research hotspot in the catalytic purification of diesel engine exhaust. In this paper, glucose is used as a complexing agent to successfully prepare a series of praseodymium and/or potassium doped La–Ni-based perovskite catalysts. The La0.9Pr0.05K0.05NiO3 catalyst exhibits the best catalytic performance when NO2 is present in the environment, with values of T10, T50, and T90 at 287, 331, and 361 °C, respectively. The CO2 selectivity reaches over 98% and has good thermal stability. Through characterization experiments, it was found that the co-doping of Pr and K can lead to the formation of oxygen vacancies by changing the valence state of Ni atoms, thereby increasing the adsorption and activation centers of reactive oxygen species, and enhancing the oxygen storage capacity of the catalyst through the redox cycle between Pr3+ and Pr4+.