5A zeolite supported nickel catalysts for methane synthesis

Abstract

5A zeolite (LTA 5A) was employed as nickel catalyst support for carbon dioxide hydrogenation at various concentrations of nickel, i.e. i.e. 5, 10, 15 and 20wt%. The catalysts were simply prepared by incipient wetness impregnation and nickel nitrate hexahydrate was employed as precursor. Calcination of catalyst at 650°C is related to thermal decomposition. Prior to carbon dioxide hydrogenation, reduction of catalysts was conducted at 600°C for 2 hours. Carbon dioxide methanation was carried out under atmospheric pressure at different temperatures varied from 200 to 500°C. The carbon dioxide was mixed with hydrogen at stoichiometric ratio of 1:4 and the catalyst composed of 15wt% nickel was the most active catalyst amongst others and gave nearly 80% of CO2 conversion and selectivity to methane was found at 60% whereas thermodynamic equilibrium gave % conversion nearly to 50% and 100% selective to methane. Increasing nickel more than 15wt% can cause agglomeration of nickel particles and lowering catalytic activity.