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

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 (2.4 nm) catalysts for methane combustion, which enable CH4 total oxidation at a low temperature of 350 °C, much lower than that of a commercial Pd/Al2 O3 catalyst (425 °C). Importantly, unexpected stability was observed even under harsh conditions (800 °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).