Ag@Pt核壳结构纳米粒子催化剂在电催化过程中的失效分析

通过种子生长法和自组装技术合成Ag@Pt核壳结构纳米粒子(以下简称Ag@Pt粒子),测量和比较在电催化循环伏安扫描(以下简称CV扫描)过程中失效前后的Ag@Pt粒子对甲醇的电催化性能的变化,采用透射电镜、高分辨电镜、X射线光电子能谱等方法研究其失效机理.结果表明：Ag@Pt粒子在循环伏安扫描的过程中会发生空化现象,其临界电压为0.5 V,空化现象随时间的增长而变得明显；Ag@Pt粒子空化后形成由Ag包覆空心Pt壳的纳米粒子,这是导致其在对甲醇进行电催化氧化过程中催化性能明显下降的原因.

Invalidation analysis of Ag@Pt core-shell nanoparticle catalysts in the electrocatalytic process

Ag@Pt core-shell nanoparticles ( Ag@Pt NPs) composed of an Ag nanoparticle core and a Pt shell were prepared by the seed-mediated growth method and self-assembly technology. The electrocatalytic properties of Ag@Pt NPs to methanol before and after invalidation were measured and compared during the electrocatalytic process. The invalidation mechanism was studied by trans-mission electron microscopy, high-resolution electron microscopy, and X-ray photoelectron spectroscopy. The results show that the cavitation phenomena of Ag@Pt NPs occur during the cyclic voltammetry process with a threshold voltage of 0. 5 V and become more obvious with the increase of time. Ag@Pt particles turn into Pt hollow shells coated by Ag after cavitation, which is the reason that the catalytic property of Ag@Pt NPs to methanol distinctly decreases during the electrocatalytic process.