Decomposition of PF₃ on Ni(755) and coadsorption with ethylcyclohexane: Comparing the results of PF₃ with CO

Temperature-programmed desorption spectra for exposure of PF₃ on Ni(755) are characterized by two desorption features around 350 and 650 K. The lower temperature feature is assigned to the molecular desorption and the higher one to the recombinative desorption of PF₃ fragments, respectively. The results suggest that the decomposition of PF₃ occurs at the step sites but not on the terrace of Ni(755). Coadsorbed PF₃ inhibits the decomposition of ethylcyclohexane almost completely and the inhibiting effect of PF₃ is more effective than that of CO. We can obtain the same decomposition starting temperature (the temperature where an adsorbed hydrocarbon starts to decompose) of ethylcyclohexane by using the inhibiting effects of PF₃ and CO.