CO2 HYDROGENATION UNDER PRESSURE ON CATALYSTS PT-CA C/

CO2 hydrogenation has been performed on a Pt-Ca/C catalyst. In a previ ous TPR study, this sample has shown the highest activity among differ ent carbon supported platinum catalysts. In the present work the Pt-Ca /C catalyst is tested in isothermal experiments (between 473 and 573 K ) at pressures of 0.1, 1 and 2 MPa. The obtained results allow a compa rison with other catalytic systems that reveals the high activity of t his catalyst to hydrogenate CO2 and the positive effect of the Pt-Ca c ombination. This catalyst, however, presents a high selectivity to CO2 that does not change with increasing pressure. To complete the study of the reaction (CO2 hydrogenation) on the Pt-Ca/C catalyst, some kine tic data, like the reaction order and the activation energy, have also been calculated. The activation energy obtained in this study is 82 k J/mol; the reaction orders for H-2 and for CO2 are very similar and th ey vary between 0.24 and 0.47 depending on the reaction conditions.