The catalytic conversion of CO2 to CH4 (Sabatier reaction) has been studied to develop an after-treatment process at vehicles exhausts. Three different formulations of Ru commercial catalysts, two in powder and one in pellets shape, were tested and characterized by means of X-ray powder diffraction, scanning electron microscopy (SEM-EDX), N-2 adsorption at -196 degrees C and temperature-programmed reduction (TPR). Experimental results show a high CO2 conversion (X-CO2 = 0.96 @ T = 280 degrees C) for one powder catalyst formulation whereas the other one has maximum CO2 conversion = 0.69. In both cases a high CH4 selectivity is measured. High CO2 conversion (X-CO2 = 0.92 @ different behavior of the catalysts was ascribed to the different physicochemical properties and the key parameters for the application development of the process were identified. In particular, the possibility to use pellets or monolithic reactors, thus minimizing the pres- sure drops in the reactor, makes possible a commercial application in the treatment of vehicles exhausts. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.