Temperature programmed desorption of Bi on Ni(100)

Abstract

The temperature programmed desorption (TPD) spectra of Bi from Ni(100) are characteized by a large shift of the desorption maximum to lower temperatures with increasing coverage. Similar behavior is observed for the desorption of Bi from other metal substrates. Analysis of the desorption of Bi from Ni(100) was performed to determine the kinetic order of desorption and the energetics of the Bi–Ni interaction. We find that Bi desorption is described well by first‐order kinetics with a strong coverage dependence of the activation energy of desorption Ed. The value of Ed varies from 70 kcal mol−1 at low Bi coverage to 57 kcal mol−1 for monolayer Bi coverage. We discuss the possible role of Bi2 in the desorption process and also report the effect of coadsorbed oxygen on the Bi TPD spectrum and the Bi–Ni interaction.