Ammonia adsorption and decomposition on a Ni(110) surface

Abstract

We report UPS/XPS results for ammonia adsorption and decomposition on a Ni(110)‐surface. At T<130 K molecular adsorption of NH3 is observed to proceed with an initial sticking coefficient of s0∠0.1. Increasing the temperature of the nickel surface above 150 K results in partial dissociation of the adsorbed NH3 molecules. The intermediate species are tentatively identified by their photoelectron spectra as NH‐fragments. At temperatures above 350 K only atomic nitrogen is observed to populate the surface after NH3‐exposures. Our data show a similar reactivity of the Ni(110) surface in the NH3‐decomposition reaction as found on iron‐single crystal planes. We briefly discuss this result with respect to the negligible activity of nickel as a catalyst for ammonia formation.