CO chemisorption on Pd; Effect of segregated phosphorus

Abstract Auger Spectroscopy and Thermal Desorption Spectroscopy were used to determine the effect of P on the activation energy for desorption of Co from a Pd foil. The Co chemisorption energy on a clean Pd surface was coverage dependent, with a low coverage value of 32 kcal/mole, in agreement with results for monocrystal low index faces. On a P segragated surface, however, a coverage independent CO chemisorption energy of 26 kcal/mole was observed. From the shape of the P(L 23 VV) Auger line, it is concluded that segregated P is not in its elemental form.