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.