Impact of the Local Environment of Amines on the Activity for CO₂ Hydrogenation over Bifunctional Basic – Metallic Catalysts

Bifunctional basic-metallic catalysts proved to be efficient for the selective hydrogenation of CO₂ to methanol. The activity of these catalysts depends on the cooperative interaction between the amine groups and metallic sites, which is a function of amine group density, Pd particle perimeter length and the geometric properties of support pores. The pore width has the highest effect on the activity, increasing the methanol yield by about half an order of magnitude. Confining the space leads to a three-dimensional utilization of the available metal surface sites compared to a two-dimensional distribution of the bifunctional sites in larger pores, where the metal particle diameter is the decisive factor for the catalytic properties.