Improvement of Ni/Al2O3 Catalysts for Low-Temperature CO2 Methanation by Vanadium and Calcium Oxide Addition

CO2 methanation is a very promising technology for the production of alternative fuels with the simultaneous use of greenhouse gases. Therefore, intensive research is carried out on the optimization of catalysts with excellent properties for operation in the area of low temperatures. Here, we present research on a catalyst composed of 19 wt % NiO supported on alumina/calcium aluminate. The catalyst was modified with V2O5 in order to be suited for extrusion and scale-up in the frame of power to gas technology. Samples with various vanadium contents (Ni-xV, where x represents the amount of vanadium) were prepared in the form of ground granules obtained from 0.5 mm diameter spherical grains. X-ray diffraction (XRD), transmission electron microscopy (TEM), skeletal infrared (IR), diffuse reflectance ultraviolet-visible-near-infrared (DR-UV-vis-NIR), and X-ray photoelectron (XPS) spectroscopies, as well as H-2 temperature-programmed reduction (H-2-TPR), were used to characterize the samples. Catalytic performances of the catalyst samples were tested in CO(2 )hydrogenation at 1 atm. Among the many supported Ni catalysts tested in our laboratories, the catalysts of 0.5 and 1 wt % V showed very high activity, with the highest CH4 yield of 97% at 623 K. These catalysts exhibited 100% CH4 selectivity up to 673 K. The excellent performances of the studied catalysts are attributed to the possible formation of Ni-V solid solution alloy nanoparticles.