Novel Mn-Ce bi-oxides loaded on 3D monolithic nickel foam for low-temperature NH3-SCR de-NOx:Preparation optimization and reaction mechanism

This study explored the superior citrate method(CM) to synthesize Mn-Ce bi-oxides on 3 D monolithic Ni-foam(NF) catalysts for the selective catalytic reduction of NO by NH3(NH3-SCR).The 17 wt% Mn(7)Ce(3)Ox/NF(CM-17) catalyst shows the NOxconversion of 98.7% at 175℃ and 90% in the presence of 10 vol% H2O.It is revealed that the combination of surface-active oxygen(formed by high-level oxygen vacancies) and strongly oxidized Mn4+species promots the Fast-SCR reactions,in which Mn4+species play a leading role in NH3-SCR reaction,and the unsaturated Ni atoms and also Ce3+species promote electron exchange and thus improve the redox performance.The coexistence mechanisms of Fast-SCR reactions and E-R pathways are observed over Mn-CeOx/NF catalyst,which may be promoted by the Br?nsted sites at low temperature.In addition,the heat resistance,stability,3 D monolithic porous structure and excellent physical properties of foam nickel provide a unique growth substrates for catalysts preparation and reaction sites for NOxpurification.Therefore,industrial application of Mn-Ce bioxides loaded on 3 D monolithic is proposed to be achieved through reasonable preparation methods.