Chemisorption of ethanol at Pt(111) and Pt(111)–O surfaces

Abstract

The chemisorption of ethanol at Pt(111) and Pt(111)–O surfaces has been studied using X-ray photoelectron (XP) and UV photoelectron (UP) spectroscopies. At atomically clean Pt(111) at 295 K only chemisorbed hydrocarbon species are present, identical spectra being observed with propene chemisorption. An oxygen-modified Pt(111) surface (ϑ₀=0.1) is also reactive but, in this case, both hydrocarbon and oxygenated species are present at 295 K. Chemisorption of acetaldehyde indicates that decarbonylation is facile, lending support for the step-wise mechanism proposed with ethanol. Studies at low temperature (200 K) also support a step-wise mechanism with an oxygenated species, possibly an ethoxide (C₂H₅O), being the intermediate. The presence of surface carbon at an otherwise clean Pt(111) surface leads to similar reactivity to C₂H₅OH as does Pt(111)–O.