An XPS Study of Formaldehyde and Related Molecules Adsorbed on the Surface of a Tungsten(100) Single Crystal.

摘要

X-ray photoelectron spectroscopy has been used to study the adsorption and catalytic decomposition of formaldehyde on a W(100) single crystal. Comparison with the 0(1s) spectra of CO(ads), CO2(ads) and O(ads) has been carried out in an attempt to understand the surface complexes formed from H2CO. It has been shown that H2CO dissociates at 100 K upon adsorption up to ca. I/2 monolayer. Above this coverage, condensation of undissociated H2CO occurs. A surface complex leading to the liberation of CO2 from the formaldehyde layer has been detected by XPS. However, no complex uniquely related to an intermediate which yields a small quantity of CH4 has been detected by XPS. (Author)