School of Nano Technology and Nano Bionics, University of Science and Technology of China, Hefei 230026, China.
Division of Advanced Nanomaterials, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences (CAS), Suzhou 215123, China.
ACS Nano. 2023 May 23;17(10):9487-9500. doi: 10.1021/acsnano.3c01690. Epub 2023 May 2.
The use of ordered catalyst layers, based on micro-/nanostructured arrays such as the ordered Nafion array, has demonstrated great potential in reducing catalyst loading and improving fuel cell performance. However, the size (diameter) of the basic unit of the most existing ordered Nafion arrays, such as Nafion pillar or cone, is typically limited to micron or submicron sizes. Such small sizes only provide a limited number of proton transfer channels and a small specific area for catalyst loading. In this work, the ordered Nafion array with a pillar diameter of only 40 nm (D40) was successfully prepared through optimization of the Nafion solvent, thermal annealing temperature, and stripping mode from the anode alumina oxide (AAO) template. The density of D40 is 2.7 × 10 pillars/cm, providing an abundance of proton transfer channels. Additionally, D40 has a specific area of up to 51.5 cm/cm, which offers a large area for catalyst loading. This, in turn, results in the interface between the catalyst layer and gas diffusion layer becoming closer. Consequently, the peak power densities of the fuel cells are 1.47 (array as anode) and 1.29 W/cm (array as cathode), which are 3.3 and 2.9 times of that without array, respectively. The catalyst loading is significantly reduced to 17.6 (array as anode) and 61.0 μg/cm (array as cathode). Thus, the nanosized Nafion array has been proven to have high fuel cell performance with low Pt catalyst loading. Moreover, this study also provides guidance for the design of a catalyst layer for water electrolysis and electrosynthesis.
有序催化剂层的使用，基于微/纳米结构阵列，例如有序的 Nafion 阵列，在降低催化剂负载和提高燃料电池性能方面显示出巨大的潜力。然而，大多数现有有序 Nafion 阵列（如 Nafion 柱或锥）的基本单元的尺寸（直径）通常限制在微米或亚微米尺寸。如此小的尺寸仅提供有限数量的质子传递通道和用于催化剂负载的小比表面积。在这项工作中，通过优化 Nafion 溶剂、热退火温度和从阳极氧化铝氧化物（AAO）模板剥离的模式，成功制备了直径仅为 40nm 的有序 Nafion 阵列（D40）。D40 的密度为 2.7×10 根/厘米，提供了丰富的质子传递通道。此外，D40 的比表面积高达 51.5 厘米/厘米，为催化剂负载提供了大面积。这反过来又使得催化剂层和气体扩散层之间的界面更加接近。因此，燃料电池的峰值功率密度分别为 1.47（作为阳极的阵列）和 1.29 W/cm（作为阴极的阵列），分别是没有阵列的 3.3 倍和 2.9 倍。催化剂负载显著降低至 17.6（作为阳极的阵列）和 61.0μg/cm（作为阴极的阵列）。因此，纳米级 Nafion 阵列已被证明具有高的燃料电池性能和低的 Pt 催化剂负载。此外，这项研究还为水电解和电合成的催化剂层设计提供了指导。
