Reactions of formaldehyde on W(100) and W(100)-(5 × 1)C

The reactions of formaldehyde on W(100) and W(100)-(5 × 1)C surfaces were studied by temperature-programmed reaction spectroscopy (TPRS). The clean W(100) surface was very reactive, completely decomposing formaldehyde upon adsorption at 300 K. The W(100) surface passivated by either adsorbed CO(β) or adsorbed carbon adsorbed formaldehyde nondissociately which reacted to form methane and methanol. Methane was formed from adsorbed methoxy groups complexed with hydrogen. The reactions of formaldehyde on W(100) and W(100)-(5 × 1)C were found to be very similar to the reactions of methanol. Two differences that were observed were (i) methyl formate was a major reaction product from the reactions of H₂CO on a carbide surface, but only a minor product from CH₃OH, and (ii) there was a second reaction pathway leading to methane formation from H₂CO that was not observed for CH₃OH. These differences have been attributed to lateral interactions among adsorbed species on the surface.