of supported Pt metal particles.21 Fast reduction rates in general lead to the formation of the more open Pt(110)-and Pt( 100)-like crystallographic faces. These open faces tend to be rougher and have a larger number of surface defects (steps and other imperfections). Slow reduction rates, on the other hand, favor the formation of smoother Pt(l 1 l)-like faces having fewer defect sites. ConclusionsThe following conclusions emerge from this study:(1) Variations in the nature of the adsorbed phase of NO depend on surface structure rather than on Pt dispersion.(2) NO is adsorbed on Pt/Si02 to give three distinct surface species. These include linearly adsorbed NO, bridge-bonded NO, and vibrationally coupled NO.(3) The collapse of band A occurs primarily on a smooth Pt surface due to the formation of this vibrationally coupled NO. Pretreatment in H2 promotes the formation of vibrationally coupled NO while pretreatment in 02 hinders it.

No abstract

ESR and photoluminescence studies have clarified that UV irradiation of the small TiO2 particle in the presence of H2O leads to the formation of \overset•OH radicals, which are formed by trapping of photo-formed holes by the surface OH− groups.

No abstract

No abstract