Microwave-assisted polyol synthesis of PtCu/carbon nanotube catalysts for electrocatalytic oxygen reduction
Microwave-assisted polyol synthesis of PtCu/carbon nanotube catalysts for electrocatalytic oxygen reduction
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DOI：
10.1016/j.jpowsour.2014.11.060
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发表时间：
2015-02-01
影响因子：
9.2
通讯作者：
Bron, Michael
中科院分区：
文献类型：
--
作者：
El-Deeb, Heba;Bron, Michael
采用微波辅助多元醇合成法制备了PtCu/CNT合金电催化剂。评估了制备 pH 值和聚乙烯吡咯烷酮 (PVP) 作为稳定剂的存在对催化剂纳米结构和电催化氧还原活性的影响。催化剂在还原气氛中于400-600℃合金化6小时，并通过TEM和XRD进行表征。 XRD 图案显示 Pt 111 峰的 2 theta 发生正移，这是 Pt-Cu 合金形成的良好证据。合金纳米颗粒在低至 400 摄氏度的温度下就已形成。在不存在 PVP 的情况下获得了高度团聚的 PtCu 纳米颗粒，而添加 PVP 则产生了分散且均匀的纳米颗粒，平均粒径为 3.7 nm。如此小的颗粒是热处理/合金化步骤期间使用的相当低的温度的结果。然而，虽然 Pt 几乎完全沉积在 CNT 上，但在最终催化剂中仅发现了较小部分的 Cu。当多元醇合成过程中 pH 值升高时，还注意到高度的团聚，这归因于铜氢氧化物的沉淀。伏安脱合金后得到Pt Cu核壳催化剂。在 PVP 存在下在较高 pH 条件下制备的催化剂显示出最高的电催化活性。 (C) 2014 Elsevier B.V. 保留所有权利。
PtCu/CNT alloy electrocatalysts were prepared by microwave assisted polyol synthesis. The influence of preparation pH and the presence of polyvinylpyrrolidone (PVP) as stabilizer on catalysts nanostructure and activity towards electrocatalytic oxygen reduction was evaluated. The catalysts were alloyed at 400-600 degrees C for 6 h in reductive atmosphere, and characterized by TEM and XRD. The XRD patterns display a positive shift in 2 theta of the Pt 111 peak, which is a good evidence for Pt-Cu alloy formation. Alloy nanoparticles already form at temperatures as low as 400 degrees C. Highly agglomerated PtCu nanoparticles were obtained in the absence of PVP while PVP addition resulted in dispersed and uniform nanoparticles with a mean particle size of 3.7 nm. Such small particles are a result of the considerably low temperature used during the heat treatment/alloying step. However, while Pt is nearly completely deposited on the CNTs, only smaller fractions of Cu are found in the final catalyst. A high extent of agglomeration was also noticed when the pH during polyol synthesis was increased, which is attributed to Cu-hydroxides precipitation. Pt Cu core shell catalysts were obtained after voltammetric dealloying. Catalyst prepared at higher pH in the presence of PVP display the highest electrocatalytic activity. (C) 2014 Elsevier B.V. All rights reserved.