Cu,N-Codoped Carbon Nanodisks with Biomimic Stomata-Like Interconnected Hierarchical Porous Topology as Efficient Electrocatalyst for Oxygen Reduction Reaction

Metal,N-codoped carbon (M-N-C) nanostructures are promising electrocatalysts toward oxygen reduction reaction (ORR) or other gas-involved energy electrocatalysis. Further creating pores into M-N-C nanostructures can increase their surface area, fully expose the active sites, and improve mass transfer and electrocatalytic efficiency. Nonetheless, it remains a challenge to fabricate M-N-C nanomaterials with both well-defined morphology and hierarchical porous structures. Herein, high-quality 2D Cu-N-C nanodisks (NDs) with biomimic stomata-like interconnected hierarchical porous topology are synthesized via carbonization of Cu-tetrapyridylporphyrin (TPyP)-metal-organic frameworks (MOFs) precursors and followed by etching the carbonization product (Cu@Cu-N-C) along with re-annealing treatment. Such hierarchical porous Cu-N-C NDs possess high specific surface area (293 m(2) g(-1)) and more exposed Cu single-atom sites, different from their counterparts (Cu@Cu-N-C) and pure N-C control catalysts. Electrochemical tests in alkaline media reveal that they can efficiently catalyze ORR with a half-wave potential of 0.85 V (vs reversible hydrogen electrode), comparable to Pt/C and outperforming Cu@Cu-N-C, N-C, Cu-TPyP-MOFs, and most other reported M-N-C catalysts. Moreover, their stability and methanol-tolerant capability exceed Pt/C. This work may shed some light on optimizing 2D M-N-C nanostructures through bio-inspired pore structure engineering, and accelerate their applications in fuel cells, artificial photosynthesis, or other advanced technological fields.