Catalyzed Particulate Filter Regeneration by Platinum Versus Noble Metal-Free Catalysts: From Principles to Real Application

In this short review, results from previous investigations by our group regarding 2 % Cu/ceria-zirconia catalyst incorporated onto a lab-scale diesel particulate filter (DPF) were compiled and compared to recent results concerning commercial platinum/alumina incorporated onto a DPF, in order to explore their catalytic regeneration. Their behavior was compared to the corresponding powder catalytic activity. In this sense, NO oxidation to NO2 and NO/NO2 recycling efficiency on the soot combustion catalytic activity were investigated for different catalyst/soot ratios. The active phase incorporated onto the DPFs was checked to be mechanically stable and reproducible in terms of amounts. Results show that catalytic activity towards NO oxidation to NO2 remains essentially constant after several cycles for both DPF-supported catalysts. It was also found that soot combustion rates presented by Pt/alumina-DPF (in 1:3 soot/catalyst ratio) and CuO/ceria-zirconia-DPF (in 1:5 soot/catalyst ratio) are very similar. It reveals that this noble metal-free catalyst can be competitive compared to a commercial platinum-based one, regarding soot combustion reaction in a particulate filter.