Optimizing the Microstructure of SnO 2 -CeO 2 Binary Oxide Supported Palladium Catalysts for Efficient and Stable Methane Combustion.

The preparation of palladium-based catalysts with both high catalytic activity and hydrothermal stability currently appears as a critical topic in methane combustion. Herein, we propose a facile strategy to boost the performance of SnO 2 -CeO 2 binary oxide supported palladium catalysts by tuning the composition of supports. The coexistence of SnO 2 and CeO 2 phases in an appropriate ratio is favorable for the formation of both Pd x Ce 1- x O 2-δ and Pd x Sn 1- x O 2-δ solid solutions due to the reduced crystallite size. This unique microstructure could enhance the metal-support interaction to stabilize the active PdO phase and promote its reoxidation, meanwhile generating more oxygen vacancies to improve the reducibility of PdO. On account of the facilitated conversion of PdO ↔ Pd, coupled with the low-temperature dissociation of methane promoted by abundant active oxygen species, the Pd/5Sn5Ce catalyst exhibits a superior catalytic activity with a T 99 of ca. 360 °C, a robust stability under both dry and wet conditions, and an excellent thermal stability during heating-cooling light-off tests.