鉑／多壁奈米碳管作為燃料電池電化學觸媒之研究

Study of platinum/multi-walled Carbon Nanotubes as Cathodicelectrocatalysts for Proton Exchange Membrane Fuel Cells

江右君(Yu-Chun Chiang) ； 邱昭瑞(Chao-Jui Chiu)

《燃燒季刊》 74期 (2011/08) Pp. 45-58

https://doi.org/10.30041/CQ.201108.0005

摘要

電化學觸媒之活性為主要影響質子交換膜燃料電池性能的關鍵因素之一，而Pt/C觸媒已知為目前應用上活性最佳的觸媒。但Pt成本相當高；因此，如何提升其利用率和耐久性乃為目前研發的重點。本研究利用反微胞法於氧化的多壁奈米碳管（CNTs和N-doped CNTs or CNx）表面合成奈米Pt粒子，探討不同碳管結構對觸媒活性之影響。研究結果發現，Pt可均勻分散在碳管表面，平均粒徑介於3-5 nm。碳管的特性會影響沈積在表面之Pt的化態。CNx的純化不會影響表面含氮官能基的種類和比例，且可提高其反應性。但純化後的CNx利用反微胞法於其表面沈積Pt粒子時，會出現碳管斷裂的現象。導致觸媒樣本的阻抗增加，進而影響燃料電池效能。本研究所合成之最佳觸媒是以CNTs為基材的樣本，其ESA可達47.7平方公尺/g，400 cycles後的衰減率約5.2%，Pt利用率可達93%；燃料電池效能為560 mA/平方公分@ 0.6V，最大功率密度可達815 mW/平方公分。

關鍵字

奈米碳管 ； 電化學觸媒 ； 反微胞法 ； 活性 ； 燃料電池

並列摘要

The activity of electrocatalysts is crucial to the performance of proton exchange membrane fuel cells and Pt/C nanoparticles are widely used catalysts with high activity at present. However, the cost of Pt is too high. Therefore, improvement of the Pt utilization and durability is of great interest recently. The Pt nanoparticles deposited on multi-walled carbon nanotubes (CNTs and N-doped CNTs or CNx) using reverse micelle method were prepared in this study and the effects of the properties of nanotubes were discussed. The results showed that Pt nanoparticles with a mean size of 3-5 nm were uniformly dispersed on the surface of nanotubes. The properties of nanotubes will affect the chemical states of Pt nanoparticles. The purification of CNx is insignificant to the types and distribution of nitrogen-containing functional groups and could increase the activity of nanotubes. But the purified CNx was cut during the synthesis process of Pt nanoparticles, this resulted in increase of impedance and decrease in performance of fuel cells. The best electrocatalyst in this study was CNTs-based, which had an electrochemical surface area (ESA) of 47.7 m^2/g with a decay of 5.2% after 400 cycles and a Pt utilization of 93%, and a fuel cell performance of 560 mA/cm^2 @ 0.6V and 815 mW/cm^2.

並列關鍵字

carbon nanotubes ； electrocatalyst ； electrochemical surface area ； activity ； fuel cell