VOx promoted Ni catalysts supported on the modified bentonite for CO and CO2 methanation

Ni catalysts supported on the raw bentonite (RB) and the acid-alkali treated bentonite (B), which were prepared by the impregnation method, were tested for methanation of CO2 and CO respectively to produce synthetic natural gas (SNG). XRD, nitrogen adsorption, SEM, TEM, TG, H-2-TPR, and XPS were employed for the characterization of the samples. The results showed that the Ni catalysts supported on the B support were more active than that supported on the RB support because of the improved Ni particles dispersion on the former that had larger specific surface area. After addition of proper amount of the VOx promoter, the catalytic activity of the B supported catalysts was further improved. This could be attributed to the enhanced H-2 uptakes, increased Ni dispersion, reduced Ni nanoparticle size, and the electronic effect of VOx that can promote dissociation of CO in the methanation reaction. In the lifetime test of CO2 and CO methanation under atmospheric pressure, the Ni/B catalysts promoted by the VOx promoter were highly stable as they had superior anti-coking and anti-sintering performance to the catalyst without the promoter. This type of the catalysts is promising for industrial production of SNG. (C) 2014 Elsevier B.V. All rights reserved.