Iron- and nitrogen-doped carbon (Fe-N-C) represents a promising class of alternative electrocatalysts to noble metals for the oxygen reduction reaction (ORR) in acidic environments. To make Fe-N-C active, one of the most critical parameters is microporosity, which must be controlled to maximize the active site density. However, the use of microporosity must be optimized for the requirement of high-flux mass transport. Here, we synthesized and demonstrated gyroidal mesoporous Fe-N-C with microporous pore walls as an avenue to combine a high active-site density with favorable mass transport at high flux. The gyroidal mesoporous Fe-N-C catalysts have competitive gravimetric and volumetric ORR activities, comparable to the ORR activity obtained in purely microporous configurations despite having mesoporous features. Our result suggests that the ORR activity of microporous Fe-N-C electrocatalysts can be combined with mesoporosity through the use of mesoporous Fe-N-C with microporous pore walls. We further investigate effects of the nitrogen incorporation method on mesoporous N-doped carbon electrocatalysts. We find that despite having ∼2 higher N concentration, nitrogen incorporation via NH₃ yields similar ORR activity to incorporation via a chemical additive, a finding we attribute to the role of pyridinic and quaternary N in the ORR.

铁和氮掺杂的碳（Fe-NC）代表了有希望的一类替代贵金属的电催化剂，用于酸性环境中的氧还原反应（ORR）。要使Fe-NC具有活性，最关键的参数之一是微孔率，必须对其进行控制以使活性位点密度最大化。但是，必须针对高通量传质的要求优化微孔的使用。在这里，我们合成并证明了具有微孔壁的螺旋形介孔Fe-NC，它是结合高活性位点密度和高通量的良好质量传输的途径。螺旋形介孔Fe-NC催化剂具有竞争性的重量和体积ORR活性，尽管具有介孔特征，但与纯微孔构型中获得的ORR活性相当。我们的结果表明，通过使用具有微孔壁的介孔Fe-NC，可以将微孔Fe-NC电催化剂的ORR活性与介孔性结合。我们进一步研究了氮掺入方法对中孔氮掺杂碳电催化剂的影响。我们发现尽管氮浓度高出约2，但氮的掺入通过NH ₃产生的ORR活性与通过化学添加剂掺入的ORR活性相似，这一发现归因于吡啶和季氮在ORR中的作用。