Physical Chemistry Laboratory, Department of Chemistry, Aristotle University of Thessaloniki Thessaloniki, Greece ; Centre for Research and Technology Hellas, Chemical Process and Energy Resources Institute Thessaloniki, Greece.
Department of Physics, Aristotle University of Thessaloniki Thessaloniki, Greece.
Front Chem. 2014 Jun 10;2:29. doi: 10.3389/fchem.2014.00029. eCollection 2014.
Ternary Pt-Ru-Ni deposits on glassy carbon substrates, Pt-Ru(Ni)/GC, have been formed by initial electrodeposition of Ni layers onto glassy carbon electrodes, followed by their partial exchange for Pt and Ru, upon their immersion into equimolar solutions containing complex ions of the precious metals. The overall morphology and composition of the deposits has been studied by SEM microscopy and EDS spectroscopy. Continuous but nodular films have been confirmed, with a Pt ÷ Ru ÷ Ni % bulk atomic composition ratio of 37 ÷ 12 ÷ 51 (and for binary Pt-Ni control systems of 47 ÷ 53). Fine topographical details as well as film thickness have been directly recorded using AFM microscopy. The composition of the outer layers as well as the interactions of the three metals present have been studied by XPS spectroscopy and a Pt ÷ Ru ÷ Ni % surface atomic composition ratio of 61 ÷ 12 ÷ 27 (and for binary Pt-Ni control systems of 85 ÷ 15) has been found, indicating the enrichment of the outer layers in Pt; a shift of the Pt binding energy peaks to higher values was only observed in the presence of Ru and points to an electronic effect of Ru on Pt. The surface electrochemistry of the thus prepared Pt-Ru(Ni)/GC and Pt(Ni)/GC electrodes in deaerated acid solutions (studied by cyclic voltammetry) proves the existence of a shell consisting exclusively of Pt-Ru or Pt. The activity of the Pt-Ru(Ni) deposits toward methanol oxidation (studied by slow potential sweep voltammetry) is higher from that of the Pt(Ni) deposit and of pure Pt; this enhancement is attributed both to the well-known Ru synergistic effect due to the presence of its oxides but also (based on the XPS findings) to a modification effect of Pt electronic properties.
在玻璃碳基底上电沉积 Ni 层，然后将其浸入含有贵金属配合物的等摩尔溶液中，部分交换为 Pt 和 Ru，制备得到三元 Pt-Ru-Ni 沉积在玻璃碳基底上的 Pt-Ru(Ni)/GC。采用扫描电子显微镜（SEM）和能量色散光谱（EDS）对沉积层的整体形貌和组成进行了研究。结果证实得到了连续但呈结节状的薄膜，其 Pt、Ru 和 Ni 的原子组成比为 37%、12%和 51%（对于二元 Pt-Ni 对照体系为 47%、53%）。通过原子力显微镜（AFM）直接记录了薄膜的形貌和厚度。通过 X 射线光电子能谱（XPS）研究了外层的组成以及三种金属之间的相互作用，得到了 Pt、Ru 和 Ni 的原子组成比为 61%、12%和 27%（对于二元 Pt-Ni 对照体系为 85%、15%），表明外层富含 Pt；仅在存在 Ru 的情况下才观察到 Pt 结合能峰向高值移动，这表明 Ru 对 Pt 具有电子效应。在空气饱和酸溶液中（通过循环伏安法研究），制备的 Pt-Ru(Ni)/GC 和 Pt(Ni)/GC 电极的表面电化学表明，存在一个仅由 Pt-Ru 或 Pt 组成的壳层。通过慢电位扫描伏安法研究发现，Pt-Ru(Ni) 沉积层对甲醇氧化的活性高于 Pt(Ni) 沉积层和纯 Pt，这归因于 Ru 的氧化物的协同作用以及 Pt 电子性质的修饰效应。
