Poly(vinylpyrrolidone)-modified graphite carbon nanofibers as promising supports for PtRu catalysts in direct methanol fuel cells
Poly(vinylpyrrolidone)-modified graphite carbon nanofibers as promising supports for PtRu catalysts in direct methanol fuel cells
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DOI：
10.1021/ja072367a
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发表时间：
2007-08-15
影响因子：
15
通讯作者：
Yeh, Chuin-Tih
中科院分区：
文献类型：
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作者：
Hsin, Yu Lin;Hwang, Kuo Chu;Yeh, Chuin-Tih
采用聚乙烯吡咯烷酮（PVP）接枝法和酸氧化法对人字形石墨碳纳米纤维（GNF（H））、多壁碳纳米管（MWCNT）和炭黑进行了表面改性，并通过FTIR、TGA、拉曼、HRTEM、XRD和XPS等手段对改性前后的碳纳米材料进行了表征。1.8nm的Pt纳米颗粒均匀地沉积在所有PVP接枝的碳纳米材料上。系统地研究和比较了两种表面改性工艺对Pt/C纳米复合材料的分散性、平均Pt颗粒尺寸、电催化性能和电导率的影响。结果发现，PVP接枝的碳纳米材料具有更少的电导率损失，因此具有更好的电催化性能，比其相应的酸氧化处理的纳米复合材料高17-463%。Pt-碳纳米复合材料的电催化性能按以下顺序降低：Pt-PVP-GNF（H）> Pt-PVP-MWCNTarc > Pt-AO-MWCNTarc> Pt-PVP-MWCNTCVD> Pt-AO-MWCNTCVD> Pt-XC-72 R> Pt-AO-GNF（H），其中Pt-PVP-GNF（H）纳米复合材料具有比Pt-Vulcan XC-72 R纳米复合材料高出约270%的性能。此外，PtRu-PVP-GNF（H）在0.6V的施加电压下显示出比Pt-PVP-GNF（H）纳米复合物更好的电催化活性（高50%）。
Carbon nanomaterials, including herringbone graphite carbon nanofibers (GNF(H)), multiwalled carbon nanotubes (MWCNT), and carbon black, were surface-modified by a new poly(vinylpyrrolidone) (PVP) grafting process as well as by the conventional acid-oxidation (AO) process, and characterized by FTIR, TGA, Raman, HRTEM, XRD, and XPS measurements. Pt nanoparticles of 1.8 nm were evenly deposited on all PVP-grafted carbon nanomaterials. The effects of the two surface modification processes on the dispersion, average Pt nanoparticle sizes, the electrocatalytic performance, and electrical conductivities of Pt-carbon nanocomposites in direct methanol oxidation were systematically studied and compared. It was found that the PVP-grafted carbon nanomaterials have much less loss in the electric conductivity and thus better electrocatalytic performance, 17-463% higher, than their corresponding acid oxidation-treated nanocomposites. The electrocatalytic performance of the Pt-carbon nanocomposites decreases in the following order: Pt-PVP-GNF(H) > Pt-PVP-MWCNTarc > Pt-AO-MWCNTarc > Pt-PVP-MWCNTCVD > Pt-AO-MWCNTCVD > Pt-XC-72R > Pt-AO-GNF(H), with the Pt-PVP-GNF(H) nanocomposite having similar to 270% higher performance than that of the Pt-Vulcan XC-72R nanocomposite. In addition, PtRu-PVP-GNF(H) shows even better (50% higher) electrocatalytic activity than the Pt-PVP-GNF(H) nanocomposite at a 0.6 V applied voltage.