کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
189707 | 459684 | 2011 | 7 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: The effect of electrochemical CO annealing on platinum–cobalt nanoparticles in acid medium and their correlation to the oxygen reduction reaction The effect of electrochemical CO annealing on platinum–cobalt nanoparticles in acid medium and their correlation to the oxygen reduction reaction](/preview/png/189707.png)
This paper describes a modification of the surface properties of a carbon-supported Pt3Co catalyst resulting from an electrochemical cycling treatment in a 0.1 M HClO4 and in a CO-saturated 0.1 M HClO4 solution (electrochemical CO-annealing). The procedure generated a Pt-rich surface with electrochemical properties different from that presented by the as-received (untreated) sample. This was evidenced by a shift in the CO stripping peak to more positive potentials in the CO stripping voltammetry, and by an increased charge of Hupd region and a modification of the oxide reduction peak observed in the base cyclic voltammogram. In situ X-ray absorption spectroscopy experiments conducted in the dispersive mode revealed differences in the electronic 5d band occupancy after the CO annealing, whereas the behavior of the intensity of the white-line as function of the potential for this material approached that found for pure Pt/C nanoparticles, in contrast to the small potential dependence profile exhibited by the as-received Pt3Co nanoparticles. Mass activities towards the oxygen reduction reaction measured by rotating disk experiments carried out at 1600 rpm in a O2-saturated solution at 25 °C increased from 0.10 A/mg of Pt to 0.19 A/mg of Pt, evidencing the higher Pt utilization in the CO-annealed Pt3Co/C electrocatalyst. The origin of the different electrochemical behavior is discussed.
► Modification of the surface properties of Pt3Co/C electrocatalyst.
► Electrochemical CO annealing in acid media generated a Pt-rich surface.
► In situ XAS revealed modifications in the Pt 5d band occupancy after CO annealing.
► The CO-annealed sample exhibited stronger interaction with oxygenated species.
► Increased Pt utilization in the CO-annealed Pt3Co/C electrocatalyst.
Journal: Electrochimica Acta - Volume 58, 30 December 2011, Pages 172–178