Effect of A-site disubstituted of lanthanide perovskite on catalytic activity and reaction kinetics analysis of coal combustion

Abstract

Perovskite catalysts are increasingly devoted to the field of coal combustion due to their special crystal structure and excellent catalytic effect. In this study, the lanthanide perovskite type catalyst La(0.8−x)Sr0.2KxMnO3 (x is the doping amount of K+) was prepared by sol-gel method, and the effect of K+ amount on the catalytic activity for coal combustion was investigated in detail. The catalyst was well characterized and the thermal dynamic parameters of coal catalytic combustion were calculated by the single reaction (SR) model and the distributed activation energy (DAE) model. The results show that the doping amount of K+ affects the specific surface area and particle size of the catalyst, due to the relatively large ionic radius of K+ and the effect of doping on the valence of other cations. The highest combustion reaction rate was achieved over La0.66Sr0.2K0.14MnO3, and it will change the specific surface area and particle size of the catalyst extremely. The dynamic calculation shows that there is a compensation relationship between the activation energy and the frequency factor. The DAE model can get the variation of activation energy in different reaction stages, and the final calculation results are in good agreement with the experimental results.