Dry reforming of methane over Co–Mo/Al2O3 catalyst under low microwave power irradiation

Abstract

In this work, microwave (MW) irradiation was used to activate Co/Al₂O₃, Mo/Al₂O₃, and Co–Mo/Al₂O₃ catalysts for dry reforming of methane (DRM) reactions. Experimental results indicate that single metallic catalysts of either Co or Mo are inactive for DRM under all the tested conditions due to their limited MW-absorbing ability. In contrast, Co–Mo bimetallic catalysts supported by Al₂O₃ exhibit high catalytic activity due to the formation of a magnetodielectric Co_0.82Mo_0.18 alloy, which plays the dual role of a good MW acceptor and the provider of active centers for the DRM reaction. The MW power level required to activate such bimetallic catalysts for DRM is significantly dependent on the molar ratio between Co and Mo. The CoMo2 catalyst (with a molar ratio of 2.0 Co to 1.0 Mo) supported on Al₂O₃ exhibits the best catalytic performance, converting 80% CH₄ and 93% CO₂ to syngas at a ratio of H₂/CO of 0.80 at the total volumetric hourly space velocity (VHSV) of 10 L g⁻¹ h⁻¹ and MW power of 200 W. As compared to the reported C-based catalysts, the Co–Mo/Al₂O₃ catalyst delivers more favorable stability over 16 time-on-stream (TOS) by virtue of its intrinsic ability to absorb MW without the inclusion of auxiliary MW acceptors.