Effect of carbon oxygen functionalization on the activity of Pd/C catalysts in hydrogenation reactions

Abstract

This paper presents a study on the effects of oxygen functionalities on a mesoporous and graphitized carbon support (GNP, Graphene Nanoplatelets), on the catalytic activity of Pd/GNP catalysts in hydrogenation reactions. A functionalization method in liquid phase has been employed, using different oxidants (HNO3, H2O2, KMnO4), with the aim to tune the amount and the type of introduced oxygen functionalities. Preformed Pd nanoparticles have been used as Pd‐precursor to limit differences in metal particle size and dispersion on differently functionalized carbon. The catalytic behaviour in benzaldehyde hydrogenation/hydrogenolysis to benzyl alcohol and toluene revealed that the introduction of oxygen functionalities has a generally detrimental effect. NMR relaxometry studies highlighted the weaker interaction between the carbonyl group and the functionalized Pd/GNP surface than the non‐functionalized Pd/GNP demonstrating that the origin of the different catalytic activity lies on the first step of the reaction. O‐functionalities also impacted on the Pd0/Pd2+ ratio at the surface which is an established parameter correlated to the reaction rate.