Porous cobalt, nitrogen-codoped carbon nanostructures from carbon quantum dots and VB12 and their catalytic properties for oxygen reduction

The porous cobalt, nitrogen-codoped carbon materials (Co/N/C) were synthesized by a facile one-step pyrolysis of vitamin B12 (VB12) and carbon quantum dots (CQDs). Varying the initial mass ratio of CQDs and VB12 leads to controllable concentrations of Co (0% to 3.68%) and N (0% to 5.88%) after pyrolysis. The obtained Co/N/C was evaluated by oxygen reduction reaction (ORR) in both alkaline and acid media. Particularly, the Co/N/C with 1.12% Co and 2.92% N prepared at 700 degrees C (Co-1.12/N-2.92/C-700) exhibited the best catalytic ability for ORR with a cathodic peak at -0.165 and 0.185 V (vs. SCE) in 0.1 M KOH and 0.1 M HClO4 solution, respectively, which are comparable to that of Pt/C (20%). The Co-1.12/N-2.92/C-700 also showed long-term stability and high methanol tolerance, which outperformed commercial Pt/C (20%).