Design of catalyst layers by using paper-like fiber/metal nanocatalyst composites for efficient NO_X reduction

The facile and effective immobilization of metal nanoparticles (NPs), such as PtNPs and CuNPs, on a microstructured paper-like matrix was successfully carried out by a direct in situ synthesis of metal NPs on ZnO whiskers embedded in a ceramic paper matrix. In the reduction process of nitrogen oxide for exhaust gas purification, the as-prepared PtNPs@ZnO paper exhibited excellent catalytic performance as compared with conventional Pt-loaded honeycomb catalysts, indicating that the paper-like microstructure promotes the effective transfer of heat and reactants to the highly efficient Pt nanocatalyst. In addition, the catalyst layer was tailored by varying the stacking patterns of PtNPs@ZnO and CuNPs@ZnO papers, leading to more than 85% reduction of the precious Pt usage compared with the case of honeycomb catalysts. Thus the metal NPs@ZnO paper composites are expected to be promising catalytic materials in making effective use of limited-availability noble metals in future sustainable societies.