Pt纳米微粒自组装体系的电化学和原位FTIR反射光谱研究

用化学还原法制备了铂金属纳米微粒 ,透射电子显微镜 (TEM)表征纳米Pt微粒的平均直径为 2 5nm。通过二硫醇将Pt纳米微粒组装到多晶金电极表面。以Fe(CN) 4- 3-6 的氧化还原作为探针反应的电化学研究表明 ,Au表面组装二硫醇后抑制了电极 /溶液界面的电子传递过程 ,而在二硫醇上再组装铂纳米微粒后 ,电子传递又可进行。运用电化学FTIR反射光谱研究了Pt纳米微粒组装电极在酸性介质中CO的吸附 ,检测到CO的线型、桥式吸附态 ,分别在 2 0 30和 184 5cm- 1 附近给出红外吸收谱峰 ,并且有增强红外效应。此外 ,还观察到Pt纳米微粒上的CO孪生吸附态。红外吸收峰位于 2 10 0cm- 1 附近。

Self-Assembly and Characterization of Pt Nanoparticles by Electrochemistry and In-Situ FTIR Reflection Spectroscopy

Pt nanoparticles (Pt(n)) were prepared by chemical reduction method. The average dimension of Pt(n) is about 2.5 nm in diameter determined from TEM studies. The Pt nanoparticles were then self-assembled on massive Au substrate. The process of self-assembly was investigated with Fe(CN)(4-/3-)(6) for redox probe reaction. The result showed that the dithiol assembled on Au surface is inactive for electron transfer. However after assembly of Pt nanoparticles on the dithiol, the Au/SS-Pt(n) electrode becomes conductive again for electron transfer. The adsorption of CO on the Pt nanoparticles self-assembled on Au substrate in 0.1 mol x L(-1) H2SO4 was studied by using in situ FTIR reflection spectroscopy. IR absorption of linear and bridge bonded CO species was observed around 2030 and 1845 cm(-1) respectively. IR absorption of twin bounded CO adsorbed on the Pt nanoparticles was also observed about 2100 cm(-1). The results illustrated that the IR absorption of CO adsorbed on the Pt nanoparticles has been significantly enhanced. The present study is devoted to revealing the intrinsic properties of self-assembly system of nanoparticles, and is of importance in applications of electrocatalysis as well.