A COMPARISON OF NO INTERACTION WITH STEPPED Pt AND Ru FIELD EMITTER SURFACES

The adsorption and the catalytic decomposition of NO on Pt and P.u field emitter surfaces has been studied by pulsed field desorption mass spectrometry (PFDMS). A molecular adsorption of NO vas found on stepped Pt(lll) and (001) surfaces in the absence of electrostatic fields. From the temperature dependence of the nean lifetimes before thermal desorption an activation energy Ed= 153 kJ/ral and a pre-exponential term T = 5 x 10" sec have been evaluated. These values are considered as representative for desorption from steps. The formation of surface oxides at temperatures T=535...6C2 K was observed for stepped Pt(001), but not for stepped (111) surfaces. The time dependence of the PtO intensity is due to a consecutive reaction mechanism. Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1986252