ChemInform Abstract: Alkane Activation: Adsorption and Reaction of n‐Butane on Clean and Carbided W(100).

Abstract

The adsorption and reaction of n‐butane have been investigated on clean and carbided W(100) surfaces using temperature programmed reaction spectroscopy, Auger electron spectroscopy, low energy electron diffraction, and isotopic exchange methods. For the clean surface, the initial adsorption probability is 1.0 at a crystal temperature of 130 K. At low coverages, butane adsorbed at 130 K converts to a dissociated state with unit probability below 200 K during temperature programmed reaction. Higher exposures result in a decrease in the adsorption probability and the onset of molecular butane desorption in the range of 150–200 K. A weakly adsorbed molecularly bound butane state is observed for all coverages on the [13 −10] and (5×1) carbide surfaces. Studies using n‐butane‐d10 show a dramatic isotope effect. The low coverage dissociation probability of n‐C4D10 is significantly less than unity and the saturation amount of decomposition in a temperature programmed reaction experiment is less than for n‐C4H10....