Engineering crystalline CoOOH anchored on an N-doped carbon support as a durable electrocatalyst for the oxygen reduction reaction

Abstract

Finding highly active, low-cost and stable electro-catalysts for the oxygen reduction reaction is challenging but crucial for several applications such as fuel cells and metal batteries. Herein, we report a novel electro-catalyst of crystalline CoOOH anchored on an N-doped carbon support through a facile method, and we explore its origin of activity via investigating the correlation between the composition of the catalyst and its electrochemical properties. Nitrogen is successfully incorporated into a carbon support, and CoOOH is desirably anchored on a carbon matrix forming Co–N coordination sites in the catalyst, which is revealed to be responsible for the much enhanced oxygen reduction activity compared to the oxygen reduction activities of the electrocatalysts having either single-doped nitrogen or anchored CoOOH species in a carbon support. Furthermore, it is deduced that the active sites for enhanced oxygen reduction can be attributed to Co–N_x, carbon atoms neighboring the doped nitrogen and even the CoOOH species. The optimized catalyst CoOOH@NC-175/300 shows lower onset potential and half-wave potential and much better cyclic stability compared to those of the state-of-the-art Pt/C catalysts. This novel finding provides a new approach for the rational engineering of low-cost, highly active and stable non-precious ORR electrocatalysts for applications in energy conversion and storage.