Metal–organic frameworks-inspired design of highly efficient nitrogen-doped carbon nanoflower electrocatalysts for Zn–air batteries

Metal–organic frameworks (MOFs) have received considerable investigation as oxygen reduction reaction (ORR) catalysts. Despite their excellent catalytic activity, many questions regarding the relationship between their structure and performance remain to be answered. In addition, these catalysts are facing slow reaction process, low raw material utilization, environmental pollution and other potential problems. Herein, inspired by the concept of MOFs, we create a remarkably homogeneous hierarchical N-doped carbon nanoflower (NCNF- m , m represents levodopa content) by a simple, fast and green pyrolysis-induced strategy using amino acid-zinc chelate and levodopa (L-dopa) as carbon and nitrogen sources. L-dopa is oxidatively polymerized and participates in the coupling process of amino acid-zinc chelates to form polymers, and the nanoflower structure is achieved under the induction of high-temperature gasification and dezincification. The structure and morphology of NCNF- m are significantly influenced by the L-dopa content. The as-prepared NCNF-1 has a hierarchical porous structure, more optimized N configurations, high specific surface area (921.88 m 2 g −1 ) and mesopore volume fraction (55.67%), exhibiting excellent electrochemical activity and cycling stability. It is also comparable to commercially available Pt/C catalysts when designed as a cathode catalyst for Zn–air batteries, suggesting its potential for useful applications. This MOF-mimicking catalyst with abundant reactive centers will provide valuable advice for the creation and fabrication of metal-free catalysts for diverse electrocatalytic processes involving energy production. Graphical Abstract One-step pyrolysis of polymers of amino acid-zinc chelates and levodopa endows NCNF-1 with the most complete nanoflower structure, the most mesoporous structure and the best N configuration, thus leading to much improved ORR performance.