Cobalt doped nanoporous hollow carbon spheres as novel non-precious metal oxygen reduction electrocatalysts

• Preparation of cobalt doped nanoporous hollow carbon sphere as ORR catalyst
• Favoring 4e ORR pathway, similar to ORR catalyzed by Pt–C catalyst
• Higher stability and tolerance to crossover effect compared to Pt–C catalyst
• A novel non-precious metal ORR catalyst

In this work, we reported the synthesis of a new non-precious metal oxygen reduction reaction (ORR) electrocatalyst made from polymer. A nitrogen-containing polydopamine (PDA) was prepared and bonded with cobalt (Co) for the forming of Co doped PDA nanoporous hollow carbon sphere (PDA-HCS-Co). The freshly prepared PDA-HCS-Co exhibits a similar surprisingly high ORR activity in alkaline solution, compared to commercial Pt–C catalyst but far exceeding Pt–C catalyst in stability and tolerance to crossover effect. The high electrocatalytic activity of PDA-HCS-Co arises from numerous pores and high content of cobalt–nitrogen species (Co–N, 67.3% of all cobalt species), which plays an important role in promoting the ORR activity.