Performance of K and Ni substituted La1−xKxCo1−yNiyO3−δ perovskite catalysts used for soot combustion, NOx storage and simultaneous NOx-soot removal

► La1−xKxCo1−yNiyO3−δ show better performance for soot combustion and soot-NOx removal. ► More Co4+ ions and oxygen vacancies are formed in La1−xKxCo1−yNiyO3−δ catalysts. ► Substituted catalysts La1−xKxCo1−yNiyO3−δ possess larger amount of adsorbed oxygen. ► Soot combustion activation energy is largely decreased by simultaneous substitution.