A density functional theory study of hydrogen dissociation and diffusion at the perimeter sites of Au/TiO2

Abstract

Reactivity of supported gold catalysts is a hot topic in catalysis for many years. This communication reports an investigation on the dissociation of molecular hydrogen at the perimeter sites of Au/TiO(2) and the spillover of hydrogen atoms from the gold to the support using density functional theory calculations. It is found that the heterolytic dissociation is favoured in comparison with homolytic dissociation of molecular hydrogen at the perimeter sites. However, the surface oxygen of the rutile TiO(2)(110) surface at these sites can be readily passivated by the formed OH, suggesting that further dissociation of molecular hydrogen may occur at pure gold sites.

On the Limited Role of Electronic Support Effects in Selective Alkyne Hydrogenation: A Kinetic Study of Au/MOx Catalysts Prepared from Oleylamine‐Capped Colloidal Nanoparticles

“…Our recent study on H 2 oxidation found that, in the presence of Ti−OH, the fastest H 2 activation pathway was via heterolytic activation at the MSI, resulting in a formal hydride developing on the Au and a proton migrating to the support . Similar heterolytic H 2 activation mechanisms have been proposed previously to explain Haruta's H 2 /D 2 equilibration work, and Sun et al .’s DFT calculations …”

Importance of surface carbide formation on the activity and selectivity of Pd surfaces in the selective hydrogenation of acetylene

“…The selectivity of ethylene formation can be calculated by comparing the hydrogenation barriers and the desorption barriers of ethylene. The latter values are estimated with the absolute values of ethylene adsorption energy, as reported previously [24,[49][50][51][52]. The adsorption energies and hydrogenation barriers of ethylene over Pd(100), Pd(100)-0.25C and Pd(100)-0.50C surfaces are listed in Table 2.…”

Sites for the selective hydrogenation of ethyne to ethene on supported NiO/Au catalysts

“…It seems that the higher hydrogenation activity of Au/TiO 2 is due to specific metal-support interaction. Fujitani [36] study [37] proved this phenomenon. Yong revealed the favored heterolytic dissociation of H 2 with E a 00.37 eV at the perimeter sites of Au/TiO 2 , where Au atom and a nearby surface O (s) 2− were involved.…”

“…As a result of this process, oxygen atoms near the perimeter were passivated. Further H 2 dissociation occurred on pure gold atoms via a homolytic mode with E a 00.64 eV [37].…”