The adsorption and desorption of CO on the Ag-rich and Pd-rich surface of Ag-Pd al-loy have been investigated with work function measurement, Auger spectroscopy （AES）,and thermal desorption spectroscopy （TDS） in a...The adsorption and desorption of CO on the Ag-rich and Pd-rich surface of Ag-Pd al-loy have been investigated with work function measurement, Auger spectroscopy （AES）,and thermal desorption spectroscopy （TDS） in an ultrahigh vacuum system, respectively.AES showed that the surface of the alloy (X<sub>Pd.bulk</sub>=40% at.) was rich in Ag after an-ncaling as would normally be expected and was rich in Pd after Ar<sup>+</sup> bombardment possiblycaused by different sputtering rate on account of their different surface binding energy.Afteradmission of CO the work functions of both surfaces （Pd-rich and Ag-rich） are raised. Theresults of AES and work function measurement confirmed that the Ag-rich alloy becamecnriched with Pd upon prolonged contact with CO at 293 K. With TDS, one singledesorption peak of adsorbed CO was observed throughout the whole range of exposure forthe Ag-Pd system. This result implied that Pd atom in the surface were acting as individualchemisorption centers and that the Ag atoms were merely acting as a展开更多
基金Research supported by Chinese Universities Science and Technology Foundation Grant.
文摘The adsorption and desorption of CO on the Ag-rich and Pd-rich surface of Ag-Pd al-loy have been investigated with work function measurement, Auger spectroscopy （AES）,and thermal desorption spectroscopy （TDS） in an ultrahigh vacuum system, respectively.AES showed that the surface of the alloy (X<sub>Pd.bulk</sub>=40% at.) was rich in Ag after an-ncaling as would normally be expected and was rich in Pd after Ar<sup>+</sup> bombardment possiblycaused by different sputtering rate on account of their different surface binding energy.Afteradmission of CO the work functions of both surfaces （Pd-rich and Ag-rich） are raised. Theresults of AES and work function measurement confirmed that the Ag-rich alloy becamecnriched with Pd upon prolonged contact with CO at 293 K. With TDS, one singledesorption peak of adsorbed CO was observed throughout the whole range of exposure forthe Ag-Pd system. This result implied that Pd atom in the surface were acting as individualchemisorption centers and that the Ag atoms were merely acting as a
