The successful in situ synthesis of platinum nanoparticles (PtNPs) on a microstructured paperlike matrix, comprising ceramic fibers as main framework and zinc oxide whiskers as selective support for the PtNPs, is reported. The as-prepared hybrid material (PtNPs@ZnO "paper") resembles ordinary paper products because it is flexible, lightweight, and easy to handle. In the catalytic reduction of nitrogen oxide (NO(x)) with propene for exhaust gas purification, the PtNPs@ZnO paper demonstrates a high catalytic performance at a low reaction temperature, with one-third the dosage of precious platinum compared to conventional platinum-loaded honeycomb catalysts. These results imply that the combination of easily synthesized PtNPs and a unique fiber-network microstructure can provide excellent performances, promoting the effective transport of heat and reactants to the active sites of the platinum nanocatalysts. Thus, PtNPs@ZnO materials with paperlike practical aspects are promising catalytic materials for efficient NO(x) gas purification.