Kinetics of CO2 methanation over Ru/γ-Al2O3 and implications for renewable energy storage applications

Kinetics of CO2 hydrogenation over a 10% Ru/gamma-Al2O3 catalyst were investigated using thermogravimetric analysis and a differential reactor approach at atmospheric pressure and 230-245 degrees C. The data is consistent with an Eley-Rideal mechanism where H-2 gas reacts with adsorbed CO2 species. Activation energy, pre-exponential factor and reaction orders with respect to CO2, H-2, CH4, and H2O were determined to develop an empirical rate equation. Methane was the only hydrocarbon product observed during CO2 hydrogenation. The activation energy was found to be 66.1 kJ/g-mole CH4. The reaction order for H-2 was 0.88 and for CO2 0.34. Product reaction orders were essentially zero. This work is part of a larger study related to capture and conversion of CO2 to synthetic natural gas. (C) 2015 Published by Elsevier Ltd.