本项目旨在构筑质子交换膜燃料电池三维分子催化膜电极体系。 核心思想是将高性能非铂氧还原催化剂以分子形式嵌入离子导电聚合物网络体系中，形成聚合物包覆复合电极。通过某些特殊而稳定的键合方式，将催化剂附着在电解质聚合物的侧链端，能够允许质子、氧气和水有效传输。这种三维分子催化层的巨大优势在于底物（包括氧气、质子、电子等）能够以三维方向接近催化活性中心，从而使得每一个催化剂分子都可以得到有效利用。 将设计几何尺寸小且高效的催化剂，并提供足够的本征催化活性和活性中心数量，以满足燃料电池膜电极对于厚度一定的催化层在大电流密度放电时的需求。相应的三维分子催化膜电极将在真实燃料电池中进行测试，所获取的各项动力学参数将用于宏观模型计算以优化电极结构。膜电极的寿命和稳定性是特别需要关注的问题。将考察各种因素对于聚合物骨架、聚合物本身支链配体、配体与催化剂的结合、催化剂自身性能等稳定性影响，并寻求有效解决方案。

The specific objective of this proposal is to use of polymer-coated electrodes that can be incorporated into Membrane Electrode Assemblies (MEA) to prepare three-dimensional arrays of catalysts in proton exchange membrane fuel cell (PEMFC) electrodes to replace expensive platinum group metal catalysts. The concept is to use polymer-coated electrode systems with tethered metal catalysts to polyelectrolyte materials that are capable of allowing transport of proton, oxygen and water to provide the benefits of redox catalysis to the oxygen reduction reaction (ORR). The great advantage of the 3D catalysis layer stems from the three-dimensional approach of the substrates (O2, H+, e-) towards the catalytic active center, and the complete usage of every single molecular catalyst. This project seeks to design small and efficient catalysts that can provide the site density and intrinsic catalytic activity to support high current densities at low overpotentials in practical MEAs and provide improved performance over scarce and expensive platinum group metal catalysts. These MEA systems will be tested in full cell systems to provide the basis for building a prototype cell stack. Durability of the catalysts and catalyst layers will be a central concern in this project. However, there is evidence from the literature and from biological examples that this problem is tractable for both the catalyst centers and the polymer matrices. For the later instance, perfluorinated polymers will be tested to mitigate instability problems.