Research Progress in Catalysts for Removal of Soot Particulates from Diesel Engines

The emission of soot particulates from diesel engines has led to serious atmospheric pollution. It is necessary to apply oxidation catalysts to increase the oxidation rate of the soot particulates at lower temperature because they cannot be normally burnt off in the exhaust stream. A large number of candidate oxidation catalysts and their catalytic mechanisms were summarized and discussed, including alkali metal or alkali earth metal catalysts, noble metal catalysts,transitional metal catalysts and composite compound catalysts. Two types of contacts, loose and tight ones, between the soot particulates and the added catalysts were also identified. The latest research progress of these catalysts was summarized,and some tentative suggestions were also put forward for their practical problems and potential application prospects.