Presently, the practical application of Fe/N/C catalysts as replacements of Pt for oxygen reduction reaction is still limited by insufficient activity. Herein, we demonstrate a novel design for such catalyst. On one hand, the obtained Fe/N/CSiO₂ZnCl₂ catalyst owns high densities of well-exposed active-sites derived from three-dimensional well-balanced macro-, meso-, and microporous structures constructed by adopting ZnCl₂ salt and SiO₂ microspheres as combined templates. On the other hand, simulation reveals that a high loading of catalyst in cathode catalyst layer would not benefit cell performance and fast oxygen reduction reaction process occurs only inside a limited thickness of catalyst layer. Particularly, the Fe/N/CSiO₂ZnCl₂ shows a maximal output power density as high as 480 mW cm⁻² at an ultra-low loading of 0.5 mg cm⁻². This study firstly exhibits that development of catalysts with high-density active sites and construct of ultra-thin catalyst layer are of great significance for improving the performance of fuel cell.

目前，Fe / N / C催化剂作为氧还原反应用Pt的替代品的实际应用仍然受到活性不足的限制。在本文中，我们证明了这种催化剂的新颖设计。一方面，所获得的Fe / N / C SiO ₂ ZnCl ₂催化剂具有高密度的暴露良好的活性位点，该活性位点是通过采用ZnCl ₂盐和二氧化硅₂微球作为组合模板。另一方面，模拟表明，阴极催化剂层中催化剂的高负载量不会有益于电池性能，而快速的氧还原反应过程仅在有限厚度的催化剂层内发生。特别地，在 0.5mg cm ^-2的超低负荷下，Fe / N / C SiO ₂ ZnCl ₂显示出高达480mW cm ^-2的最大输出功率密度。这项研究首先表明，开发具有高密度活性位点的催化剂和构建超薄催化剂层对提高燃料电池的性能具有重要意义。