Single and double-bed stacked wire mesh cartridges for the catalytic treatment of diesel exhausts

Abstract

Stacked stainless steel wire mesh monoliths were developed as supports for Pt/Co,Ce catalysts for diesel exhausttreatment. After the calcination of the metal structures at 900 °C, a Co,Ce layer was deposited over the meshes bymeans of an equimolar suspension of Co3O4 and CeO2 nanoparticles, followed by the incorporation of 1 wt.% Pt.Also, a double bed catalyst configuration was studied: a Pt,CeO2 pre-filter diesel catalyst oxidation (DOC) wasdeveloped to efficiently oxidize NO to NO2 which helps in regenerating the accumulated soot within the Co,Cecatalyzed diesel particulate filter (DPF). The catalytic monoliths, both as single and double bed configurations,were evaluated for the simultaneous combustion of volatile organic compounds (ethyl acetate, n-hexane ortoluene) and soot. Co,Ce and Pt/Co,Ce structures presented similar catalytic activities, with a maximum sootcombustion rate at 420 °C, whereas this value decreased to 400 °C for the double bed catalyst. Catalytic experimentswith or without gaseous O2 or NO in the feed were carried out to ascertain the role of the catalyticcomponents. The structured and powder catalysts were characterized by X-ray diffraction (XRD), scanningelectron microscopy (SEM), Brunauer?Emmett?Teller (BET), energy dispersive X-ray spectroscopy (EDX) andLaser Raman spectroscopy. The catalyst coating adherence was confirmed by ultrasound tests and the pressuredrop of the catalytic structures was measured.