Analytische Chemie-Elektroanalytik & Sensorik, Ruhr-Universität Bochum, 44780 Bochum, Germany.
Chemphyschem. 2009 Oct 19;10(15):2711-8. doi: 10.1002/cphc.200900496.
Pt-Ag nanoparticle co-deposits with different Pt-Ag ratios were prepared on a glassy carbon (GC) surface by pulsed electrodeposition and investigated for their catalytic activity in electrocatalytic oxygen reduction by using cyclic voltammetry (CV), rotating disc electrode (RDE) and scanning electrochemical microscopy (SECM) in 0.1 M phosphate buffer (pH 7.0). The atomic composition of the Pt-Ag co-deposits was studied by means of energy-dispersive X-ray analysis (EDAX). In combination with X-ray diffraction (XRD), the presence of partly alloyed Pt and Ag on the GC surface was confirmed. Scanning electron microscopy (SEM) images indicate that the prepared Pt-Ag catalyst particles are homogenously dispersed over the GC surface. Their size and morphology depend on their composition. The electrocatalytic activity of Pt-Ag deposits with high Pt content was the highest, exceeding even that of electrodeposited Pt as evaluated by quantitative RDE analysis. The redox competition mode of scanning electrochemical microscopy (RC-SECM) was successfully used to visualize the local catalytic activity of the deposited Pt-Ag particles. Semi-quantitative assessment of the SECM results confirmed the same order of activity of the different catalysts as the RDE investigations.
通过脉冲电镀在玻璃碳（GC）表面制备具有不同 Pt-Ag 比的 Pt-Ag 纳米颗粒，并通过循环伏安法（CV）、旋转圆盘电极（RDE）和扫描电化学显微镜（SECM）在 0.1 M 磷酸盐缓冲液（pH 7.0）中研究其在电催化氧还原中的催化活性。采用能谱分析（EDAX）研究了 Pt-Ag 共沉积的原子组成。结合 X 射线衍射（XRD），证实了 GC 表面上部分合金化的 Pt 和 Ag 的存在。扫描电子显微镜（SEM）图像表明，制备的 Pt-Ag 催化剂颗粒在 GC 表面上均匀分散。它们的尺寸和形态取决于它们的组成。高 Pt 含量的 Pt-Ag 沉积物的电催化活性最高，甚至超过了通过定量 RDE 分析评估的电沉积 Pt 的电催化活性。扫描电化学显微镜的氧化还原竞争模式（RC-SECM）成功地用于可视化沉积的 Pt-Ag 颗粒的局部催化活性。SECM 结果的半定量评估证实了不同催化剂的活性顺序与 RDE 研究相同。
