Fibrous spherical Ni-M/ZSM-5 (M: Mg, Ca, Ta, Ga) catalysts for methane dry reforming: The interplay between surface acidity-basicity and coking resistance

A highly active and robust fibrous spherical ZSM-5-supported nickel catalyst with different promoters (Mg, Ca, Ta, Ga) have been synthesised by microemulsion method for dry reforming of methane (DRM). The structural framework provided by the unique fibrous spherical ZSM-5 aided confinement of Ni particles. Catalytic activity was improved by homogenous distribution of surface acid-basic sites, thereby reducing the propensity of coke deposition. Bimetallic Ni-Ta catalyst produced the highest CH4 and CO2 conversions at 93% and 98%, respectively, with H-2/CO ratio closer to unity (0.97). The nature of acid sites and bimetallic Ni-Ta synergism amplified interaction of catalyst components, resulting in improved interaction with the reactants, thus impeding metal sintering and coke deposition. Consequently, the Ni-Ta/FZSM-5 catalyst shows long-term activity (80 hours) for the DRM reaction at 800 degrees C.