Roth C, Benker N, Theissmann R, Nichols R J, Schiffrin D J
Department of Chemistry, The University of Liverpool, Liverpool, L69 7ZD, United Kingdom.
Langmuir. 2008 Mar 4;24(5):2191-9. doi: 10.1021/la7015929. Epub 2008 Jan 23.
Pt-Ru alloys are prominent electrocatalysts in fuel cell anodes as they feature a very high activity for the oxidation of reformate and methanol. The improved CO tolerance of these alloys has been discussed in relation to the so-called ligand and bifunctional mechanisms. Although these effects have been known for many years, they are still not completely understood. A new approach that bridges the gap between single crystals and practical catalysts is presented in this paper. Nanoparticulate model systems attached to an oxidized glassy carbon electrode were prepared by combining both ligand-stabilized and spontaneously deposited Pt and Ru nanoparticles. These electrodes showed very different voltammetric responses for CO and methanol oxidation. The cyclic voltammograms were deconvoluted into contributions attributed to Pt, Ru, and Pt-Ru contact regions to quantify the contribution of the latter to the bifunctional mechanism. Scanning transmission electron microscopy confirmed the proximity of Pt and Ru nanoparticles in the different samples.
铂钌合金是燃料电池阳极中重要的电催化剂，因为它们对重整产物和甲醇的氧化具有非常高的活性。这些合金对一氧化碳耐受性的提高已根据所谓的配体和双功能机制进行了讨论。尽管这些效应已为人所知多年，但仍未完全理解。本文提出了一种弥合单晶与实际催化剂之间差距的新方法。通过结合配体稳定的和自发沉积的铂和钌纳米颗粒，制备了附着在氧化玻碳电极上的纳米颗粒模型系统。这些电极对一氧化碳和甲醇氧化表现出非常不同的伏安响应。循环伏安图被解卷积为归因于铂、钌和铂-钌接触区域的贡献，以量化后者对双功能机制的贡献。扫描透射电子显微镜证实了不同样品中铂和钌纳米颗粒的接近性。
