Ordered Nafion® ionomers decorated polypyrrole nanowires for advanced electrochemical applications

Sun, Rongchuan; Xia, Zhangxun; Li, Huanqiao; Jing, Fenning; Wang, Suli

doi:10.1016/j.jechem.2017.07.005

Cited by 5 publications

(2 citation statements)

References 24 publications

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“…It has been proved that the ordered MEA made using the Nafion array is effective in increasing the utilization of the Pt catalyst and reducing the Pt catalyst loading and cost. ,,,, Some Nafion arrays with a high aspect ratio and density are prepared using the anodic aluminum oxide (AAO) template. − In addition, the arrays with different shapes of pillars, including the cylinder and cone, have been realized. , The array is more conducive to the efficient utilization of the Pt catalyst. At the same time, the large specific surface area of the array and the proton gradient feature provide an excellent condition for the loading of the catalyst.…”

Section: Introductionmentioning

confidence: 99%

“…28 It has been proved that the ordered MEA made using the Nafion array is effective in increasing the utilization of the Pt catalyst and reducing the Pt catalyst loading and cost. 3,22,24,29,30 Some Nafion arrays with a high aspect ratio and density are prepared using the anodic aluminum oxide (AAO) template. 31−33 In addition, the arrays with different shapes of pillars, including the cylinder and cone, have been realized.…”

Section: ■ Introductionmentioning

confidence: 99%

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Well-Dispersed Nafion Array Prepared by the Freeze-Drying Method to Effectively Improve the Performance of Proton Exchange Membrane Fuel Cells

Pan

Qin

Ning

et al. 2021

ACS Sustainable Chem. Eng.

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The ordered membrane electrode assembly (MEA) is currently the frontier research field of proton exchange membrane fuel cells (PEMFCs). The ordered MEA is effective in increasing the utilization of the Pt catalyst and reducing the Pt catalyst loading and cost. Due to a larger specific surface area and faster rate of proton transfer, a Nafion array was used to prepare a high-performance MEA. In order to realize the ideal performance, the critical mission is to make a well-dispersed Nafion array. However, the pillars in the Nafion array are prone to form bundles induced by surface tension of water, resulting in a severe reduction in the specific surface area. In this work, we successfully prepared a well-dispersed Nafion array by the freeze-drying method, which greatly improved the performance of the ordered MEA of a PEMFC. The percentage of isolated pillars in the Nafion array is improved from about 0.8% after natural drying to about 90% after freeze-drying. The specific surface area of the Nafion array membrane after freeze-drying increases to 4.74, which is 2.1 times that after natural drying, and is close to the theoretical value of 4.99, indicating that the well-isolated array possesses a larger specific surface area to load a catalyst. Consequently, the electrochemical surface area of the catalyst layer reaches as high as 131.5 m2 gPt –1, which is 1.6 or 2.5 times that with the Nafion array after natural drying or without the Nafion array. For the ordered MEA, a long-term stability is vital for PEMFC operation. In this work, the lifetime of the ordered MEA with the Nafion array after freeze-drying is excellent compared to the Nafion array after natural drying and without the array. Besides, the scanning electron microscopy characterization clearly shows that the Nafion array remains a well-dispersed structure even after hot-pressing and plays a pivotal role in PEMFC operation. Therefore, this research proves that the freeze-drying method can effectively solve the aggregation of the Nafion array during drying and further proves that the well-dispersed Nafion array could show much higher performance. More importantly, this work provides an ideal basic material for the preparation of the ordered MEA.

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