(511b) CATALYTIC Coating ON METAL Substrate for Soot OXIDATION

A simple K-containing glass (K-Si-Ca-O) has been developed in our lab and has shown good activity for diesel soot combustion by thermogravimetric analysis (TGA) under various contact and atmospheric conditions. [1] This catalyst has subsequently been applied to stainless steel substrates for catalytic testing in a simulated exhaust gas environment. The results show that a glass catalyst-coated device can lower the ignition temperature of diesel soot (Tig) to ~390oC, and offer good catalytic stability at 400oC. It suggests the feasibility of a metallic diesel particulate filter. In order to use the glass catalyst with a variety of substrates it is desirable to apply it in the form of a dip coating. Toward this end, a sol-gel approach has been developed for application of the catalytic glass. Figure 1(left) shows a sol-gel catalytic coating applied on a stainless steel wire-mesh substrate (top: bare substrate, bottom: coated substrate). Figure 2 (right) shows TGA weight loss curves for uncatalyzed and catalyzed soot combustion for real soot contact conditions. It is evident that most of the soot is oxidized well below 400oC by the glass catalyst. Additional TGA characterization based on repeated regeneration cycling has led to further improvements in the catalytic stability.