Stepwise Dissociation of Thermally Activated Phenol on Pt(111)

摘要: The thermal reactions of phenol on Pt(111), including reaction intermediates, have been studied between 125 and 1100 K by using phenol-h6, phenol-2,4,6-d3, phenol-2,3,4,5,6-d5, phenol-d6 with temperature-programmed desorption (TPD), high-resolution electron energy loss spectroscopy (HREELS), X-ray photoelectron (XPS). Phenol adsorbs molecularly at K, the ring plane parallel to surface. During heating, O−H bond breaks below 200 K. dissociation product, phenoxy, has a quinoidal structure η5-π-adsorption geometry via C2 through C6 atoms C1 atom tilted away from plane. Bonds in phenoxy species rearrange toward oxocyclohexadienyl upon heating. reactivity depends initial coverage. Below 0.5 monolayer (ML), fully decomposes CO(g), H2(g), C(a). Above 0.7 ML coverages, it follows two different pathways:  (1) 85 ± 7% forms C2(a), C3H3(a) 490 latter dehydrogenating...