American Chemical Society, Journal of Physical Chemistry C, 1(114), p. 436-441, 2009
DOI: 10.1021/jp908568v
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We have addressed the problem of determining a reliable experimental descriptor of surface chemical reactivity by measuring Pd and Ru 3d(5/2) core-level shifts of the Pd(n)/Ru(0001) pseudomorphic overlayer system (n = 0-3) by high resolution X-ray photoelectron spectroscopy. We find a linear relationship between the calculated theoretical changes of the d-band center position projected on each Ru and Pd atomic layer (which is, according to the Hammer and Norskov d-band model, a good theoretical descriptor of chemical reactivity) and the corresponding core-level shifts, both for the Ru atomic planes and for the Pd overlayers. Core-level shifts, therefore, should be considered as reliable experimental descriptors of chemical reactivity in the same sense (and with similar limitations) of the theoretical descriptor d-band center. Final-state effect contributions to the shifts do not obscure this trend.