Diesel soot combustion suffers from ignition temperatures (T10) as high as > 450 °C in the absence of catalysts, which are unavailable in diesel exhaust during normal driving cycles (normally 200–400 °C). A catalytic diesel particulate filter (CDPF) could decrease T10 greatly, but it is often inadequate due to the poor contact associated with the solid (catalyst)-solid (soot) interactions. Herein, a highly significant T10, as low as ˜200 °C, was achieved on noble metal-free ultrathin MnO2- x nanosheet array fabricated by in situ etching of a La layer from LaMnO3 under loose contact conditions in a NO-containing atmosphere. A number of advantages were found with such a system including the improved reducibility. Then, the nanosheet array ensures high dispersion of soot on the catalyst. Finally, high NO-to-NO2 oxidation activity further facilitates contact between catalyst and soot via NO2, a stronger oxidant than O2.
Bibliographical noteThis work was supported by National Natural Science Foundation of China (No. 21477046 and 21876061), Key Technology R&D Program of Shandong Province (No. 2016ZDJS11A03) and the U.S. National Science Foundation under Award No. CBET-1344792.
- Ignition temperature
- Soot combustion
- MNOX-CEO2 MIXED OXIDES
- SELECTIVE CATALYTIC-REDUCTION
- EFFICIENT CATALYST
- DIESEL EXHAUST
- MONOLITHIC CATALYSTS