CO2 conversion through combined steam and CO2 reforming of methane reactions over Ni and Co catalysts

Abstract

AbstractNi‐Co bimetallic and Ni or Co monometallic catalysts prepared for CO2 reforming of methane were tested with the stimulated biogas containing steam, CO2, CH4, H2, and CO. A mix of the prepared CO2 reforming catalyst and a commercial steam reforming catalyst was used in hopes of maximizing the CO2 conversion. Both CO2 reforming and steam reforming of CH4 occurred over the prepared Ni‐Co bimetallic and Ni or Co monometallic catalysts when the feed contained steam. However, CO2 reforming did not occur on the commercial steam reforming catalyst. There was a critical steam content limit above which the catalyst facilitated no more CO2 conversion but net CO2 production for steam reforming and water‐gas shift became the dominant reactions in the system. The Ni‐Co bimetallic catalyst can convert more than 70% of CO2 in a biogas feed that contains ~33 mol% of CH4, 21.5 mol% of CO2, 12 mol% of H2O, 3.5 mol% of H2, and 30 mol% of N2. The H2/CO ratio of the produced syngas was in the range of 1.8‐2. X‐ray absorption spectroscopy of the spent catalysts revealed that the metallic sites of Ni‐Co bimetallic, Ni and Co monometallic catalysts after the steam reforming of methane reaction with equimolar feed (CH4:H2O:N2 = 1:1:1) experienced severe oxidation, which led to the catalytic deactivation.