Abstract
We report here the solution coatings of Diesel Particulate Filter (DPF) with allylhydridopolycarbosilane (AHPCS)-based polymers leading tosupported silicon carbide (SiC)-based membranes with high temperaturesoot particle filtration efficiency, durability and catalytic activity.In a first part of the present study, our objective was to reduce thepore size of DPF to filtrate finer particles without altering filtrationefficiency by coating DPF with an additional fine porous AHPCS-derivedSiC membrane. The latter is produced by dip-coating AHPCS on DPFfollowing by a pyrolysis of the AHPCS membrane-modified DPF at 1000degrees C under argon. We investigated the influence of dip-coatingparameters and viscosity of different AHPCS solutions on the SiCmembrane-coated DPF by SEM, mercury porosimetry, XRD andhigh-temperature thermogravimetric analysis. The evolution of thefiltration capacity has been determined with a synthetic gas bench. Anadditional fine SiC membrane (-150 nm in thickness) prepared from a 10vol% of AHPCS in THE deposited on DPF allowed maintaining filtrationefficiency as high as the virgin DPF while the pore size of the SiCmembrane coated-DPF decreased to filter finer particles. Results areconfirmed using a commercially-available polysiloxane (Si-C-Oprecursor). Furthermore, the SiC membrane acted as a thermal barriercoating and provided a better durability to the DPF by preventingapparition of cracks after heat-treatment to 1500 degrees C under argon.The use of mixed oxide and metallic phases formed in-situ in SiCconstitutes one of the solutions to generate new and effective catalyticperformances to membranes. Within this context, in a second part of thestudy, we applied a reverse AHPCS-based microemulsion to combine SiCand oxide phases in the same additional porous membrane. As a proof ofconcept, we have prepared catalytically active Ce-O-Fe-Pt/SiC membranecoated DPF after dip-coating and pyrolysis under argon. These materialshave been characterized and tested with regard to CO/HC oxidation andsoot combustion. Ce-O-Fe-Pt/SiC membrane coated DPF showed an activityfor CO conversion reaching a light off temperature T-50=270 degrees Cand the presence of the catalytic phase allowed burning soot at 486degrees C. (C) 2015 Elsevier B.V. All rights reserved.