Structure Sensitivity of 2-Methyl-3-butyn-2-ol Hydrogenation on Pd: Computational and Experimental Modeling

Abstract

In the frame of DFT paradigms, the adsorption of 2-methyl-3-butyn-2-ol (MBY) and 2-methyl-3-buten-2-ol (MBE) on a Pd30 cluster, including both {100} and {111} faces, was studied along with the pathways involved in the hydrogenation, taking place on plane and low coordination (corner/edge) sites of given MBY/Pd30 and MBE/Pd30 surface configurations. The calculated energetics, further validated by gas-phase and water-assisted gas-phase MBY and MBE hydrogenation, performed on well-defined size and shape-controlled Pd nanoparticles supported on SiO2, were able to explain the origin of the structure sensitivity and the high selectivity characterizing the title reaction when occurring in aqueous solution. The C≡C moiety of the MBY surface species indeed seemed to be mostly activated by plane sites instead of corner/edge atoms, whereas the MBE species appeared to have a different behavior, with their C═C moieties typically being activated by low coordination sites. DFT studies excluded that the overhydrogenation...