Catalytic activity and influence factors of Mn-Ce mixed oxides by hydrothermal method on diesel soot combustion

• Mn-Ce catalysts have excellent catalytic performance on soot combustion because of solid solution structure and adsorbed oxygen atoms. • Catalytic activity gets the optimum when weight ratio of soot/MC-0.40 mixture is suitable at the range of 1:9–1:13, and ash shows adverse effects compared with no-ash sample. • Mn-Ce catalysts are more sensitive and show better activity in NO atmosphere because of NO adsorption/desorption. • The reusability of MC-0.40 catalyst is accepted in soot combustion studied by performing three consecutive cycles. To solve the soot elimination and optimize catalyst diesel particulate filter (CDPF) regeneration strategies, a series of Mn-Ce catalysts with different Mn/(Mn+Ce) molar ratios are successfully synthetized by hydrothermal method and the complete catalytic oxidation of diesel engine soot are investigated. Compare to CeO 2 and MnO 2 , the catalytic promotion on soot combustion of Mn-Ce catalysts is more excellent by thermogravimetric experiments due to their better ability to activate oxygen species, which is consistent with results in characterization analysis. Among as-prepared catalysts, MC-0.40 has the best catalytic activity with the lowest starting temperature ( T s ), peak temperature ( T p ) and largest comprehensive combustion index ( S ) both in O 2 /N 2 and NO/O 2 /N 2 atmosphere. Influence factors on catalytic performance are studied. Weight ratios of soot/MC-0.40 catalyst are suitable at the range of 1:9–1:13, which makes soot combustion more easily. Ashes in the reaction process show adverse effects due to their ability to increase ignition point by inhibit heat and oxygen transfer. Mn-Ce catalysts are more sensitive and show better catalytic activity in NO atmosphere because of generations of abundant adsorbed species and NO adsorption/desorption. The three consecutive cycles of MC-0.40 catalyst are performed to study the catalytic stability, and thermogravimetric curves show that the potential reusability of MC-0.40 catalyst can be relatively accepted in soot combustion.