燃料电池催化剂油墨微观结构的流变学研究,ACS Applied Materials & Interfaces

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燃料电池催化剂油墨微观结构的流变学研究
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2018-12-10 00:00:00 , DOI: 10.1021/acsami.8b15039
Sunilkumar Khandavalli ₁ , Jae Hyung Park ₂ , Nancy N. Kariuki ₂ , Deborah J. Myers ₂ , Jonathan J. Stickel ₃ , Katherine Hurst ₁ , K. C. Neyerlin ₁ , Michael Ulsh ₁ , Scott A. Mauger ₁

Affiliation

我们提出了燃料电池催化剂油墨的流变学研究。流变学结合超小角度X研究了包括炭黑载体结构，碳载体上Pt的存在（Pt–碳）和离聚物（Nafion）浓度在内的油墨参数对催化剂油墨的油墨微观结构的影响。射线散射（USAXS）和动态光散射（DLS）。高表面积碳（HSC）或科琴黑类型的分散液表现出比Vulcan XC-72碳更高的粘度，这是因为更高的内部孔隙率和更结块的结构提高了墨水的有效颗粒体积分数。两种碳载体上都存在Pt催化剂，通过静电稳定作用降低了粘度。对于纯碳分散体（无Pt），由于碳团聚体的电空间稳定作用，离聚物的加入达到临界浓度会降低粘度。但是，对于Pt-碳分散体，离聚物的添加在Vulcan和HSC载体之间表现出相反的行为。在Pt-Vulcan分散体中，离聚物添加对流变学的影响在质量上与不含Pt的Vulcan分散体相似。Pt–HSC分散体显示出随着离聚物的添加而增加的粘度和强烈的剪切稀化性质，表明Nafion可能使Pt–HSC聚集体絮凝。这些结果使用DLS和USAXS进行了验证。此外，对离聚物：碳比率的影响以及不同表面积的碳之间的比较的观察提供了对对应于优化的催化剂墨水的微观结构的见解。I / C比值代表燃料电池性能的文献报道。

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Rheological Investigation on the Microstructure of Fuel Cell Catalyst Inks

We present a rheological investigation of fuel cell catalyst inks. The effects of ink parameters, which include carbon black-support structure, Pt presence on carbon support (Pt–carbon), and ionomer (Nafion) concentration, on the ink microstructure of catalyst inks were studied using rheometry in combination with ultrasmall-angle X-ray scattering (USAXS) and dynamic light scattering (DLS). Dispersions of a high-surface-area carbon (HSC), or Ketjen black type, demonstrated a higher viscosity than Vulcan XC-72 carbon due to both a higher internal porosity and a more agglomerated structure that increased the effective particle volume fraction of the inks. The presence of Pt catalyst on both the carbon supports reduced the viscosity through electrostatic stabilization. For carbon-only dispersions (without Pt), the addition of ionomer up to a critical concentration decreased the viscosity due to electrosteric stabilization of carbon agglomerates. However, with Pt–carbon dispersions, the addition of ionomer showed contrasting behavior between Vulcan and HSC supports. In the Pt–Vulcan dispersions, the effect of ionomer addition on the rheology was qualitatively similar to Vulcan dispersions without Pt. The Pt–HSC dispersions showed an increased viscosity with ionomer addition and a strong shear-thinning nature, indicating that Nafion likely flocculated the Pt–HSC aggregates. These results were verified using DLS and USAXS. Further, the observations of the effect of ionomer:carbon ratio and a comparison between carbons of different surface areas provided insights on the microstructure of the catalyst ink corresponding to the optimized I/C ratio for fuel cell performance reported in the literature.

更新日期：2018-12-10

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