In situ measurements of change in work function of Pt, Pd and Au surfaces during desorption of oxygen by using photoemission yield spectrometer in air

• Published in: Applied surface science Vol. 363; pp. 240 - 244
• Main Authors: Yamashita, Daisuke, Ishizaki, Atsushi
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.02.2016
• Subjects: Catalyst; Desorption; Gold; Mathematical analysis; Oxygen coverage; Palladium; Photoemission; Photoemission yield measurements; Platinum; Spectrometers; Temperature dependence; Work function; Work functions; Temperature dependence; Work function; Photoemission yield measurements; Oxygen coverage; Catalyst
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2015.12.018

•In situ measurements of change in work function of Pt, Pd and Au were carried out.•Photoemission yield spectrometer with an open counter was employed.•Gradual decrease of work function during desorption of oxygen was observed.•The returning processes at higher temperatures proceed faster.•The exponential decay of work function was analyzed using chemical kinetics scheme. We investigated the change in work function of Pt, Pd and Au surfaces during desorption of oxygen by using a photoemission yield spectrometer with an open counter. Oxygen coverage was formed by UV/ozone treatment, and then continuous change in work function with exposure to air was observed at various temperatures. Work function of Pt, Pd and Au surfaces decreased during desorption of oxygen, and finally returned to the initial value of untreated surfaces. Furthermore, temperature dependence on the change in work function was found. These characteristics were explained using chemical kinetics scheme. The exponential decay of work function was well reproduced by the first-order reaction rate equation, and it was confirmed that the order of rate constant, kr, is kr(Au)<kr(Pd)<kr(Pt). The activation energy was estimated to be 36, 38 and 28kJ/mol for Pt, Pd, Au, respectively.