Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, Chiba University, Yayoi-cho 1-33, Inage-ku, Chiba 263-8522, Japan.
Chemphyschem. 2009 Oct 19;10(15):2719-24. doi: 10.1002/cphc.200900486.
Surface structures of shape-controlled Pt nanoparticles have been estimated using cyclic voltammetry (CV) and infrared reflection absorption spectroscopy (IRAS). Cubic and cuboctahedral Pt nanoparticles are prepared using a capping polymer. These nanoparticles give CVs similar to those of single crystal electrodes of Pt in sulfuric acid solution. The CV of cubic nanoparticles is similar to that of the Pt(510) [=5(100)-(110)] electrode, while the CV of cuboctahedral nanoparticles is reproduced well with the convolution of Pt(766) [=13(111)-(100)] and Pt(17 1 1) [=9(100)-(111)] electrodes. These results suggest that the planes of the cubic and cuboctahedral nanoparticles are composed of step-terrace and atomically flat terraces, respectively. Adsorbed carbon monoxide (CO) on the shape-controlled nanoparticles gives the IR bands that are assigned to on-top and bridged CO. The band of on-top CO is deconvoluted to two bands: the higher and the lower frequency bands are assigned to the CO on the plane and the edges of the nanoparticles, respectively. On-top CO adsorbed on the edges is oxidized at more negative potential than that on the planes. Edge sites of the nanoparticles promote CO oxidation.
使用循环伏安法（CV）和红外反射吸收光谱（IRAS）对形状控制的 Pt 纳米粒子的表面结构进行了估计。使用封端聚合物制备了立方和八面体 Pt 纳米粒子。这些纳米粒子在硫酸溶液中给出与 Pt 单晶电极相似的 CV。立方纳米粒子的 CV 类似于 Pt(510)[=5(100)-(110)]电极，而八面体纳米粒子的 CV 很好地再现了 Pt(766)[=13(111)-(100)]和 Pt(17111)[=9(100)-(111)]电极的卷积。这些结果表明，立方和八面体纳米粒子的平面分别由台阶-平台和原子平坦平台组成。吸附在形状控制纳米粒子上的一氧化碳（CO）给出了分配给顶和桥接 CO 的 IR 带。顶 CO 的带被分解为两个带：较高和较低的频率带分别分配给平面和纳米粒子边缘上的 CO。边缘上吸附的顶 CO 在比平面上更负的电位下被氧化。纳米粒子的边缘部位促进 CO 的氧化。
