Templated synthesis of cobalt subnanoclusters dispersed N/C nanocages from COFs for highly-efficient oxygen reduction reaction.

We first stepwise grew cobalt coordinated bipyridine-based COFs TpBpy on silica nanospheres (SiO 2 @Co-TpBpy) for preparing cobalt subnanoclusters dispersed C/N (Co-TpBpy-X) nanocages after optimizing calcination temperature and removing the silica template. The experimental and DFT calculation results indicated Co-TpBpy-800 nanocages has highly efficient ORR activity due to the ORR catalyst skips the intermediate of OOH*. These finding opens a new approach for development of high-efficient catalyst from COFs derivative for electrochemical applications. • COFs templated Synthesis of Co subnanoclusters dispersed N/C Nanocages. • The high ORR activity due to Co subnanoclusters coordinated N atoms in the carbon nanocages. • An unconventional five-step ORR process without the intermediate OOH* • The oxygen adsorption/dissociation on catalyst surface promote high-efficient ORR. Development of nonprecious metal-based electrocatalysts with highly efficient oxygen reduction reaction (ORR) has increasingly attracted wide attention in energy conversion and storage systems. In this work, we stepwise grow cobalt chelated COF TpBpy (Co-TpBpy) on silica nanospheres to form core–shell SiO 2 @Co-TpBpy nanospheres. After calcination high temperatures and removing silica template, cobalt subnanoclusters dispersed in N-doped carbon (N/C) nanocages are obtained for ORR. As a result, the Co-TpBpy-800 nanocages exhibit highly efficient activity on electrocatalytic ORR with 0.831 V of half-wave potential and high stability. Moreover, DFT calculation verifies the resulting unique nanocages reveal an unconventional five-step ORR process in which it skips the intermediate OOH* because the oxygen dissociation and adsorption directly occur on the catalyst surface. The present work will help the development of highly-efficient nonprecious metal-based catalysts for various energy applications. [ABSTRACT FROM AUTHOR]