Cluster Quantum Chemical ab Initio Study on the Interaction of NO Molecules with Highly Dispersed Titanium Oxides Incorporated into Silicalite and Zeolites

Ab initio cluster quantum chemical calculations at the Hartree−Fock (HF) level have been performed for interactions of one and two NO molecules with highly dispersed titanium oxide species incorporated into silicalite (Ti−silicalite) and zeolite (Ti−zeolite) cavities. To find the similarities and differences in the adsorption mechanism, additional calculations have also been carried out on the adsorption of these and other small molecules on pure silica, alumina−silica, and titania. It was found that the NO molecule weakly adsorbs on the Ti−silicalite and Ti−zeolite while it strongly adsorbs on the titania surface. Based on the results of these calculations, different channels of NO decomposition on the Ti−silicalite or Ti−zeolite and on pure titania are discussed.