Metal–polydopamine framework-derived (Co)/N-doped carbon hollow nanocubes as efficient oxygen electrocatalysts†
Oxygen electrocatalysis is of great significance for various energy conversion and storage-related applications. Herein, by using in situ polymerization of dopamine on specially designed metal–organic framework (MOF) nanocubes and subsequent annealing treatment, well-defined Co/N-doped carbon hollow nanocubes with high electrocatalytic activity and stability toward the oxygen evolution reaction are obtained. To attain a current density of 10 mA cm−2, the overpotential required for the Co/N-doped carbon hollow nanocubes is only 285 mV, which is comparable to that of commercial RuO2 (270 mV) and lower than those of most MOF-derived ones and other carbon supported Co-based electrocatalysts. Surprisingly, we find that when the Co nanoparticles are leached using simple acid wash, the as-synthesized N-doped carbon hollow nanocubes could act as an efficient electrocatalyst for the oxygen reduction reaction instead. The strategy presented here for controlled design and synthesis of MOF-derived hollow (metal)/N-doped carbon frameworks would offer new prospects for developing efficient oxygen electrocatalysts for electrochemical energy devices.