Promotion effects of LaCoO3 formation on the catalytic performance of Co–La oxides for soot combustion in air

•The formation of LaCoO3 in Co–La oxides promotes soot combustion in air.•The substitution of La3 + in LaCoO3 for Co2 + results in the formation of Co4 +.•Co4 + favors oxygen vacancy and promotes activities of Co1 − xLaxOy catalysts.

Co1 − xLaxOy catalysts were synthesized by citric acid complex method and their catalytic activities for soot combustion in air were investigated in this study. The best performance was observed over Co0.93La0.07 oxide catalysts with T50 = 402 °C. Co4 + in the surface of LaCoO3 leads to the formation of more oxygen vacancies, thus contributing to the activities.

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