For decades, it has been well known that the hierarchical porous structure imparts a beneficial effect for oxygen reduction reaction (ORR) electrocatalysts. However, the exact role of multimodal porous structure mostly depends on the intuition of enhanced mass transport effect. In this study, the effect of each pore modalities (meso- and microporous structure) on the electrocatalytic activity of porous carbon catalysts is investigated by combining data from physicochemical characterization and electrochemical analyses. For systematic comparison, we prepared three types of N-doped carbon model catalysts with different combinations of pore modalities. Difference in their catalytic activities is studied by electrochemical parameters in relation to the surface area. We demonstrated that meso- and micropore contribute to different stage of the ORR kinetics. We further verified the generality of porous structure engineering that improves ORR activity in both acidic and alkaline environment, regardless of the active site (N-C or Fe-N-C). We believe that our study will shed light on the rational design of porous carbon structures for various electrocatalytic applications.

Identifying the role of pore modalities in oxygen reduction for optimizing Fe-N-C electrocatalyst

2019 Fall National Meeting

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