Activity of catalysts supported on heat-resistant ceramic cloth for diesel soot oxidation

We investigated catalysts that promote the soot oxidation using a heat-resistant ceramic cloth (mullite; 70%Al2O3–30%SiO2) as a substrate for the catalyst. The catalytic activity was evaluated by a temperature (T10), at which 10% of carbon black (CB) combined with the catalyst-bearing cloth was oxidized during a temperature raise process under simulated air conditions (flow rate = 0.5 L min−1, CB = 5 mg, cloth = 0.1 g), and by a balance point temperature (BPT) assessed by the changing rate of pressure drop through the catalyst-bearing cloth with time under practical diesel exhaust conditions (flow rate = 45 L·min−1, PM concentration = 40 mg m−3, cloth = 38 g). Among the catalysts tested under the simulated conditions, Pt combined with metal oxides which have a low melting point such as V2O5 and MoO3 showed high activities (T10 = ca. 490 °C). Under the practical conditions, V2O5 + Pt-loaded cloth showed a performance of a filtration rate of 59% with a BPT of 553 °C. Mobility of the catalyst over the cloth surface and easiness of reduction and oxidation of the catalyst were suggested to be important for promotion of soot oxidation.

Soot oxidation catalyst using a heat-resistant ceramic cloth as a substrate was investigated. Pt combined with low-melting metal oxides, such as V2O5 and MoO3, showed high activities. Mobility of the catalyst over the cloth surface and easiness of reduction and oxidation of the catalyst were suggested to be important for the promotion of soot oxidation.Figure optionsDownload as PowerPoint slide