The preparation of a good catalyst starts with the selection of the appropriate support that include good textural properties such as surface area, porosity, and pore volume. The catalyst’s support plays an important role in the activity and selectivity of the catalyst. The surface area on one hand, permits loading and dispersing of the active species, while the support’s pore size will control diffusion of the reactant molecules to reach the active species that are located inside the internal area of the pores. Therefore, using the physisorption technique to elucidate the textural properties of the support, must be the first and most important task. The quimisorption techniques – normally called TPX techniques – are widely used to study the role of the support to stabilize and disperse the active species under the reaction conditions of high temperature and pressure that easily could sinter the active particles, and thus, yield a fast deactivation of the catalyst.
The Sabatier reaction was carried out in this study by reducing CO2 with H2 to produce CH4 using Ni supported catalysts. Two catalysts were used having about 5% Ni and supported on a different surface area material. Slowly increasing the reactor temperature (about 2C/min) from ambient, and online following the appearance of the products by a mass spectrometer, permits to follow step by step the evolution of the reaction and the appearance of the products as a function of the increasing temperature.
The results of this study indicated that the higher surface area catalyst produced a larger amount of CH4 and the lower sintering of the active species, and thus, online following the evolution of the reaction permits elucidates step by step the appearance of the products as a function of the increasing temperature.
