High stability of low Pt loading high surface area electrocatalysts supported on functionalized carbon nanotubes
High stability of low Pt loading high surface area electrocatalysts supported on functionalized carbon nanotubes
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DOI：
10.1016/j.jpowsour.2012.12.025
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发表时间：
2013-06
影响因子：
9.2
通讯作者：
D. Mezalira;M. Bron
中科院分区：
文献类型：
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作者：
D. Mezalira;M. Bron
采用微波辐射多元醇法合成了高比表面积、小平均粒径(2 Nm)的功能化(N，O)碳纳米管负载铂电催化剂。用物理和电化学方法对催化剂和载体的表面和结构进行了表征。通过快速电位循环监测电化学行为的变化、循环伏安法和极化曲线的加速应力测试来评价催化剂的稳定性。表征表明，所有样品的铂颗粒尺寸都是相当的，约为2 nm，铂的负载量取决于合成中使用的碳纳米管。加速应力测试表明，样品的电化学比表面积(ECSA)相对稳定，仅观察到较小的非线性衰减，远低于炭黑负载样品。值得注意的是，ECSA的损失实际上与碳纳米管的组成/功能化无关。ECSA的初始较强变化暂定归因于催化剂的初始结构变化，这种变化在碳纳米管和氧官能化碳纳米管(OCNT)负载的样品中更为明显。同时，氮化碳纳米管(NCNT)负载催化剂的表面比活性在后一组分中变化不大。
Functionalized (N, O) carbon nanotubes supported Pt electrocatalysts with high surface area and small average particle diameter (2 nm) are synthesized by the polyol method using microwave irradiation. Physical and electrochemical methods are used to characterize the surface and the structure of the catalysts and supports. The stability of the catalysts is evaluated through an accelerated stress test by fast potential cycling monitoring changes in electrochemical behavior with cyclic voltammetry and polarization curves. Characterization indicates that the Pt particle size is comparable for all samples and is about 2 nm with a Pt loading depending on the carbon nanotubes employed in synthesis. The accelerated stress test demonstrates that the electrochemical surface areas (ECSAs) are relatively stable and only a small and non-linear decay is observed, which is much lower than with carbon black-supported samples. Strikingly, the ECSA loss is virtually independent of the composition/functionalisation of the CNTs. Initial stronger changes in ECSA are tentatively attributed to initial structural changes in the catalyst, which are more pronounced for CNT and oxygen-functionalized CNT (OCNT) supported samples. Concurrently, the surface specific activity initially changes strongly in the latter samples, while it does not for the nitrogen-functionalized CNT (NCNT) supported catalysts.