N[O.sub.X] reduction over paper-structured fiber composites impregnated with pt/[Al.sub.2][O.sub.3] catalyst for exhaust gas purification

Pt/[Al.sub.2][O.sub.3] catalyst powder was successfully incorporated in a microstructured paper-like matrix composed of a ceramic fiber network, by use of a simple papermaking technique. As-prepared composite, denoted paper-structured catalyst, was applied to the reduction of nitrogen oxide (N[O.sub.X]) in the presence of propene, for exhaust gas purification. The paper-structured catalyst demonstrated higher N[O.sub.X] reduction efficiency and more rapid thermal responsiveness than a conventional Pt-loaded honeycomb catalyst, indicating that the paper-like structure with interconnected pore spaces contributes to effective transport of heat and reactants to the catalyst surfaces. Furthermore, the paper-structured catalyst with the appearance of flexible paperboard has a high degree of utility. The efficiency of utilization of Pt catalyst was improved by using hierarchically assembled paper-structured catalysts with preferential location of Pt catalyst in the upper part. The paper-structured catalyst composite with paper-like utility and porous microstructure is thought to be a promising catalytic material for efficient N[O.sub.X] gas purification.