• • The 2Pd-1Ru/S-1 catalyst achieved T50 and T90 of approximately 339 °C and 380 °C, respectively, with a stable 94% methane conversion over 48 h at 375 °C, demonstrating superior low-temperature activity and long-term stability compared to monometallic Pd/S-1.
• • Ru doping significantly enhanced water resistance: the bimetallic catalyst maintained high activity under humid conditions, attributed to the Pd-Ru electronic synergy that strengthens PdO-support interaction and reduces competitive adsorption of H2O on active sites.
• • Mechanistic analysis confirmed that PdO is the primary active phase and the reaction proceeds via the Eley-Rideal (E-R) mechanism, where gaseous oxygen is activated on the catalyst surface before reacting with gas-phase methane.
• • The hydrophobic Silicalite-1 support preserved its MFI framework and pore structure during reaction, ensuring efficient mass transfer and providing structural stability for the active phase, which is critical for industrial application under demanding conditions.