Polydopamine-Derived, In Situ N-Doped 3D Mesoporous Carbons for Highly Efficient Oxygen Reduction

N-doped mesoporous carbons (NMCs) have drawn a lot of interest as alternative electrocatalysts to replace noble metals. The maximized surface areas endow NMCs substantially increased active sites and thus greatly promote the catalytically apparent performance. Herein, polydopamine (PDA) is employed to derive NMCs by a facile hard-templating method. The newly-developed NMC-900 shows highly catalytic efficiency in oxygen reduction reaction (ORR), comparable to that of Pt/C and superb stability greatly surpassing Pt/C, attributed to its fascinating componential and structural merits. The componential-favored graphitic N and pyridinic N afforded highly efficient and stable metal-free active sites. The structurally large surface area (536 m(2)/g) and well-aligned 3D mesoporous architecture provided sufficiently exposed active sites and unimpeded reaction channels for ORR. Both the good electrical conductivity and hydrophilic surface of NMC-900 ensured an expedited ORR process.