团聚铂纳米粒子电极在甲醇氧化中的电催化特性

Electrocatalytic Properties of Agglomerates of Pt Nanoparticles in Methanol Oxidation

用H2还原法并以Nafion作为稳定剂合成团聚的Pt纳米粒子,附载于玻碳表面制备电催化剂.透射电子显微镜(TEM)和扫描电子显微镜(SEM)表征结果指出,团聚Pt纳米粒子的平均尺寸约为400nm.运用电化学循环伏安法(CV)和原位傅立叶变换红外反射光谱(insituFTIRS)研究甲醇的氧化过程,发现团聚Pt纳米粒子电极具有较高的电催化活性.原位FTIRS研究结果检测到甲醇在所制备的电催化剂上氧化的中间体为线型吸附态CO物种,其红外吸收给出异常红外效应的光谱特征.

Agglomerates of Pt nanoparticles were synthesized by using H-2 as reduction reagent and nafion as stabilizer. The electrode of agglomerates of Pt nanoparticles was prepared by dispersing the agglomerates onto glassy carbon surface and is denoted as Pt-a(ag)/GC. The average size of the agglomerates in colloid and on the surface of electrode were characterized to be around 400 nm using TEM and SEM, respectively. Cyclic voltammetry and in situ FTIR spectroscopy were employed to study electrocatalytic properties of the Pt-a(ag)/GC electrode towards methanol oxidation. It has been revealed that the agglomerates of Pt nanoparticles exhibit significant electrocatalytic activity for the oxidation of CH3OH. In comparison with CH3OH oxidation on an electrode of Pt thin film supported on Au, the oxidation potential has been shifted negatively about 300 mV on the Pt-a(ag)/GC. The results demonstrated also that the oxidation of CH3OH is a complex process, which may be influenced by the diffusion of CH3OH and controlled by the oxidation-reduction of the agglomerates of Pt nanoparticles on electrode surface. Linearly adsorbed CO species (COL) is the only intermediate that has been determined by in situ FTIR spectroscopy. The IR features Of COL illustrated that the agglomerates of Pt nanoparticles exhibit abnormal infrared effects as other kind low-dimensional nanomaterial does.