Electrochemical performance of Pd and Au-Pd core-shell nanoparticles on surface tailored carbon black as catalyst support
Electrochemical performance of Pd and Au-Pd core-shell nanoparticles on surface tailored carbon black as catalyst support
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DOI：
10.1016/j.ijhydene.2011.12.014
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发表时间：
2012-04-01
影响因子：
7.2
通讯作者：
Lazaro, M. J.
中科院分区：
文献类型：
--
作者：
Celorrio, V.;Montes de Oca, M. G.;Lazaro, M. J.
本工作研究了碳载体的表面化学对Pd和Au-Pd核壳(CS)纳米粒子电化学行为的影响。用不同的酸处理对Vulcan XC-72R进行化学修饰，改变了中孔的体积和含氧物种的表面密度。采用胶体法合成了具有19 nm Au核和10 nm Pd壳结构的CS纳米结构，并将其组装到碳载体上。将Pd前驱体浸渍到改性碳中，然后用硼氢化钠还原制备了Pd纳米粒子。通过使用不同的制备方法，可以独立研究载体对纳米颗粒的形态/分布的影响，以及通过它们与有机分子的相互作用对纳米颗粒的反应活性的影响。用X射线衍射仪、能谱、拉曼光谱和接触角测量对催化剂进行了表征。用循环伏安法和计时电流法研究了CO和甲酸的电氧化。碳载体对电催化活性的影响与制备方法密切相关。浸渍法制备的Pd纳米粒子负载在氧化程度较高的Vulcan载体上时，表现出较高的HCOOH氧化电流。这是由于含氧官能团密度高而产生了较小的颗粒尺寸(2.3 nm)。另一方面，由于特定的化学作用，CS纳米结构在高度氧化的火神中活性显著降低，这可能与氧化物的形成有关。简要讨论了这些发现对使粒子衬底相互作用合理化的意义。版权所有(C)2011，氢能出版有限责任公司。爱思唯尔有限公司出版。保留所有权利。
The present work studies the influence of the surface chemistry of carbon supports on the electrochemical behaviour of Pd and Au-Pd core-shell (CS) nanoparticles. Vulcan XC-72R was chemically modified by different acid treatments, inducing changes in the volume of the mesopores and surface density of oxygenated species. The CS nanostructures featuring 19 nm Au cores and 10 nm Pd shells were synthesized by colloidal methods and subsequently incorporated to the carbons supports. Pd nanoparticles were prepared by impregnating a Pd precursor into the modified carbons followed by reduction with sodium borohydride. The use of different preparation methods allowed the independent study of the effect of the support on the morphology/distribution of the nanoparticles and on the reactivity of the nanoparticles, through their interaction with organic molecules. The electrocatalysts were characterised by XRD, EDX, Raman spectroscopy and contact angle measurements. CO and formic acid (HCOOH) electro-oxidation were studied using cyclic voltammetry and chronoamperometry. The effect of the carbon support on the electrocatalytic activity was highly dependent on the method of preparation. Pd nanoparticles obtained by impregnation showed higher HCOOH oxidation currents when supported on the highly oxidised Vulcan support. This is due to the generation of smaller particle sizes (2.3 nm) as a result of the high density of oxygenated functional groups. On the other hand, the CS nanostructures are significantly less active in highly oxidised Vulcan as a results of specific chemical interactions which may be related to the formation of oxides. The implication of these findings towards rationalising particle substrate interactions are briefly discussed. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.