纳米材料基催化剂
双金属片
材料科学
催化作用
金属间化合物
化学工程
循环伏安法
X射线光电子能谱
电化学
无机化学
金属
纳米技术
合金
纳米颗粒
物理化学
冶金
电极
化学
生物化学
工程类
作者
Zong-Cheng Zhang,Xiangjun Tian,Binwei Zhang,Long Huang,Fuchun Zhu,Ximing Qu,Li Liu,Shuo Liu,Yanxia Jiang,Shi‐Gang Sun
出处
期刊:Nano Energy
[Elsevier]
日期:2017-04-01
卷期号:34: 224-232
被引量:83
标识
DOI:10.1016/j.nanoen.2017.02.023
摘要
Improving the CO tolerance of Pt-based catalysts is very meaningful for the application in proton exchange membrane fuel cells and direct alcohol fuel cells. The behavior of Pt-based bimetallic catalysts is depended on their phase and surface composition. In this work, we tuned the surface composition of Pt3Co nanocatalysts by heat treatment under different atmosphere. The results of atomic-resolution HAADF-STEM, XRD, XPS and electrochemical characterization demonstrated that the surface composition of Pt3Co catalysts with Co-increased, Intermetallic and Pt-increased were obtained by metal segregation approach. Due to the differences in the surface atomic distribution and alloying extent, the nanocatalysts show different CO poisoning tolerance in the order of Co-increased>Intermetallic>Pt-increased. CO stripping voltammetry and in-situ Fourier transform infrared spectroscopy (FTIRS) were used together to investigate the origin of varied CO poisoning tolerance on three Pt3Co catalysts. The results illustrated that electronic effect plays a major role in weakening CO adsorption on Pt3Co nanocatalysts and thus promoting CO oxidation to form COOHad intermediate consistent with Langmuir-Hinselwood mechanism. Oxophilic effect promotes the oxidation of COOHad intermediate into the final products CO2/CO32-. This work provides a new insight into tuning phase and surface composition of catalysts thus enhancing CO tolerance of Pt-based bimetallic catalysts.
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