NO-methanol interaction on the surface of Pt(3 3 2)

The interaction between NO and CH₃OH on the surface of stepped Pt(3 3 2) was investigated using Fourier transform infra red reflection-absorption spectroscopy (FTIR-RAS) and thermal desorption spectroscopy (TDS). At 90 K, pre-dosed CH₃OH molecules preferentially adsorb on step sites, suppressing the adsorption of NO molecules on the same sites. However, due to a much stronger interaction with Pt, at 150 K and higher, the adsorption of NO molecules on step sites is restored, giving rise to peaks closely resembling those of NO molecules adsorbed on clean Pt(3 3 2) surface. Adsorbed CH₃OH is very reactive on this surface, and is readily oxidized to formate in the presence of O₂, even at 150 K. In contrast, reactions between CH₃OH and co-adsorbed NO are slight to non-existent. There are no new peaks in association with intermediates resulting from CH₃OH-NO interactions. It is concluded that the reduction of NO with CH₃OH on Pt(3 3 2) does not proceed through a mechanism of forming intermediates.