Hollow N-doped carbon nanoflowers with nanosheets subunits for electrocatalytic oxygen reduction

The synthesis of economic carbon-based metal-free catalysts with high electroactivity for the oxygen reduction reaction (ORR) is still a huge challenge for energy storage and conversion devices. Herein, the hollow N-doped carbon nanoflowers (h-N-CFs) with nanosheets subunits were synthesized by using 3,5-diaminobenzoic acid-1,3,5-benzenetricarboxaldehyde (DABA-BTCO) complex nanoflowers as the self-template and nitrogen resource. Various physical characterizations show that h-N-CFs with hollow and porous architecture have a high surface area (1390.3 m2g−1) and abundant activated N atoms (i.e., graphitic N and pyridinic N). Electrochemical measurements demonstrate that h-N-CFs synthesized at 800 °C can be used as an efficient metal-free ORR catalyst with prominent electroactivity and stability due to hollow architecture, abundant pores, and high N-doping content. Meanwhile, h-N-CFs also show eminent ORR selectivity (i.e., methanol tolerance) in alkaline media, which markedly surpasses benchmark Pt/C catalyst in the presence of methanol.