The decomposition of surface methoxy on clean and oxygen post dosed Fe(100); control of reaction selectivity

Abstract

Pure methoxy overlayers on the Fe(l00) surface were prepared and characterized by high resolution electron energy loss spectroscopy (HREELS). Reactions of the methoxy overlayer on the clean surface and in the presence of coadsorbed oxygen have been studied using temperature programmed reaction spectroscopy (TPRS). Post-dosed oxygen alters dramatically the selectivity of methoxy decomposition. Carbon monoxide and hydrogen are the major decomposition products from a pure methoxy overlayer, while formaldehyde is the major decomposition product from an oxygen coadsorbed methoxy overlayer. Clear evidence for production of formaldehyde via a disproportionation of methoxy is presented. Coadsorbed oxygen raises the decomposition temperature of methoxy by 200 K.