Active sites for heterogeneous catalysis by functionalisation of internal and external surfaces

Computational approaches to the determination of active site structures and reaction mechanisms in heterogeneous catalysts

“…) 919 Determination of active site structures type of Ti-centred catalyst. Thus, embedded cluster calculations are in progress for the latter (and other) systems (see French et al 2004). The results, however, do show how modelling techniques, especially when used in conjunction with in situ experimental studies, can reveal the detail at the molecular level for this important catalytic cycle.…”

“…Using these detailed models of the polar surfaces of ZnO, we investigated the metal-support interaction and modelled the formation and oxidation of supported nanoclusters of gold and copper (Bromley et al 2003;Catlow et al 2003;French et al 2003bFrench et al , 2004. In this paper, we report our first attempts at combining the knowledge we have accumulated to model the reaction intermediates adsorbed on a supported cluster of copper.…”

Quantum Mechanical/Molecular Mechanical (QM/MM) Approaches

“…The material we introduced above, a Ti doped silicalite-1 (TS-1) (Taramasso et al, 1983) is a siliceous counterpart of ZSM-5, which has been of great interest, since it is used with aqueous H2O2 as the primary oxidant in a large number of important reactions such as the epoxidation of linear olefins, hydroxylation of aromatics, and oxidation of alcohols, amines, linear alkenes, sulphur compounds and ethers (Bordiga et al, 2001). (French et al, 2004;To et al, 2006a;To et al, 2006b) have proposed a number of structural models for a Ti species that would result from the framework hydrolysis and site inversion that takes place during synthesis, postsynthetic treatment and / or, depending on the catalytic process, during the catalytic transformation. The structures of interest are shown in Figure 5.…”

Electronic Effects in Organic Chemistry

“…Balcells and Maseras reviewed QM/MM studies about asymmetric catalysis. We only want to point to some recent works on the activation of C-H bonds [42], methanol synthesis from syngas [41,693], the partial epoxidation of alkenes [42] and the electron trapping at the oxygen terminated polar surfaces of ZnO and related surface F centres [43]. In these studies, the QM part typically includes the metal and these parts of the system which are directly involved in the reaction.…”