Enhancement of the catalytic performance to methanol synthesis from CO2/H2 by gallium addition to palladium/silica catalysts

Abstract

The hydrogenation of CO2 was investigated on Ga-promoted Pd/SiO2 catalysts. A 500-fold turnover rate enhancement and an increase of the selectivity to methanol synthesis, up to 70%, were found under pseudo stationary state conditions (523 K and 3 MPa) using the promoted materials as compared to Pd/SiO2. Based on apparent activation energy values and product distribution, a reaction pathway to CH3OH involving intermediates which are intrinsically associated to adsorbed CO2 is proposed. It is concluded that the Ga-Pd interaction, proved through DRS and TPR experiments, brings the catalytic performance of these Ga-Pd/silica materials close to that of the traditional Cu/ZnO-based catalyst for methanol synthesis.