Self-Assembly Synthesis of Cobalt- and Nitrogen-Coembedded Trumpet Flower-Like Porous Carbons for Catalytic Oxygen Reduction in Alkaline and Acidic Media

Developing highly cost-effective catalysts for an oxygen reduction reaction (ORR) in fuel cells is highly significant but still full of challenges. In this work, cobalt- and nitrogen-coembedded three-dimensional (3D) trumpet flower-like porous carbons (CoNC) have been prepared by a simple two-step self-assembly technique, using carbon quantum dots (CQDs) as the carbon precursor and a supermolecular gel of self-assembled melamine and Co2+ ions as the nitrogen and cobalt sources. The resultant CoNC catalysts possess unique 3D trumpet flower-like structures, efficient charge transfer ability, and abundant Co–Nx active sites. As a catalyst for ORR, the optimized CoNC-800 (pyrolyzed at 800 °C) exhibits efficient electrocatalytic activities, longer-term stability, and strong endurance to methanol both in acidic and alkaline media. It can be worked as a prospective substitute for a commercial Pt/C catalyst for ORR in the widespread implementation of fuel cells.