ETHYLENE-OXIDE ADSORPTION ON K-MODIFIED NI(111) - THERMAL STABILIZATION AND DISSOCIATION

The adsorption and desorption behavior of ethylene oxide on K-modified Ni(111) was studied in a wide range of K coverage [⊖(K) = 0 to >0.36]. In the low K coverage regime ⊖(K)<0.1, referred to as “ionic” K, the ethylene oxide adsorption is, as on dean Ni(111), molecular. The binding strength of ethylene oxide towards the K/Ni(111) surface is weak; complete desorption occurs below 250 K. In the higher K coverage regime ⊖(K) >0.36, referred to as “metallic” K, a thermal stabilization of ethylene oxide in the presence of metallic K is observed, which is due to a ring breaking of the ethylene oxide molecule and to the formation of a radical. © 1990, American Vacuum Society. All rights reserved.