Confined Ultrathin Pd-Ce Nanowires with Outstanding Moisture and SO2 Tolerance in Methane Combustion

摘要

An efficient strategy (enhanced metal oxide interaction and core-shell confinement to inhibit the sintering of noble metal) is presented confined ultrathin Pd-CeOx nanowire (2.4nm) catalysts for methane combustion, which enable CH4 total oxidation at a low temperature of 350 degrees C, much lower than that of a commercial Pd/Al2O3 catalyst (425 degrees C). Importantly, unexpected stability was observed even under harsh conditions (800 degrees C, water vapor, and SO2), owing to the confinement and shielding effect of the porous silica shell together with the promotion of CeO2. Pd-CeOx solid solution nanowires (Pd-Ce NW) as cores and porous silica as shells (Pd-CeNW@SiO2) were rationally prepared by a facile and direct self-assembly strategy for the first time. This strategy is expected to inspire more active and stable catalysts for use under severe conditions (vehicle emissions control, reforming, and water-gas shift reaction).