Construction of Pd-Ru/Silicalite-1 Bimetallic Catalysts and Their Performance and Mechanism for Complete Methane Oxidation
Complete catalytic oxidation of methane requires catalysts with high low-temperature activity, long-term thermal stability, and excellent water resistance for industrial application. This study constructed supported Pd-Ru/S-1 bimetallic catalysts using hydrophobic all-silica zeolite Silicalite-1 as support. Systematic catalytic performance tests evaluated methane oxidation activity, thermal stability, and water resistance, while multiple physicochemical characterizations revealed the reaction mechanism. Results showed that the catalyst with Pd/Ru ratio of 2:1 (2Pd-1Ru/S-1) exhibited optimal comprehensive performance, achieving T90 of 380 °C, maintaining 94% methane conversion at 375 °C for 48 h, and demonstrating excellent water resistance. Mechanistic studies indicated that PdO is the main active phase, and the reaction follows the Eley-Rideal (E-R) mechanism. The electronic synergy between Pd and Ru enhances the interaction between PdO and the support, effectively inhibiting sintering and water poisoning of active components. This study aims to provide a new strategy for industrial catalyst design to advance the industrialization of low-concentration methane catalytic technology, addressing its climate and pollution impacts.