Physical and Theoretical Chemistry

Biography

Biography: Wilke Dononelli

Abstract

Bulk gold has been known as an inert material without any specific catalytic activity for almost a century. But then in the 1970s Bond et al. presented small gold particles placed on a SiO₂ support that could be used for the hydrogenation of alkenes and alkynes. Since this decade a lot of research has been done on nanostructured gold. This Au-based catalysts can be used for fuel cells, the synthesis of esters or the selective oxidation of alcohols.

The selectivity of gold to partial oxidation products is higher than the selectivity of other metal catalysts, so there is a high interest in this gold based catalysts. A problem of gold nanoparticles as catalyst is, that the efficiency increases if the average particle size is reduced, so in most cases the major part of the surface area of the supporting material is not used for the catalytic processes.

In addition to this supported forms of gold catalysts an unsupported form of gold, the nanoporous gold (np-Au), characterized by Zielasek et. al., has recently attracted considerable interest due to its potential use in catalysis. Compared to supported gold nanoparticles the complete entire surface of the material can be possibly usable as a catalytic material.

The most prominent example for the use of np-Au as a catalyst is the selective oxidation of methanol. Although this reactions has been investigated by several groups, the origin of the catalytic activity of np-Au has not been understood completely. The main remaining question that we try to answer is the nature of the active sites of the np-Au. Within DFT (density functional theory) calculations we describe the influence of residual silver atoms in the material and try to explain some possible pathways for the activation of oxygen, the most essential step of most of oxidative coupling reactions.