MOF-Derived Oxygen Vacancy-Rich Co/CoO@NC-CNTs Hybrid Electrocatalyst for Oxygen Reduction Reaction

Graphical A Co/CoO@NC/CNT-10 catalyst was effectively synthesized using melamine-assisted pyrolysis with Co-MOF as the precursor. With the synergistic effect of metal species, oxygen defects and N-doped carbon nanotubes, the intrinsic activity and electron transfer ability of the catalysts were greatly improved, showing excellent electrocatalytic oxygen reduction performance. Low-cost and high-efficiency oxygen reduction reaction (ORR) electrocatalysts are the basis for large-scale applications of electrochemical energy storage and conversion technologies such as fuel cells and metal-air batteries. Herein, cobalt and oxygen vacancy-rich cobalt oxide encapsulated in nitrogen-doped carbon and carbon nanotubes (Co/CoO@NC-CNTs) have been prepared by direct solid-state pyrolysis of Co-MOF. The carbon morphology, oxygen vacancy content and type of nitrogen can be finely tuned by mixing Co-MOF with proper amounts of melamine. The optimized material has an interwoven CNT structure with abundant micro- and mesopores, suitable nitrogen type and certain number of oxygen vacancies and exhibiting outstanding ORR electrocatalytic performance in alkaline media with an onset potential of 0.96 V and a half-wave potential of 0.88 V vs RHE, which is higher than 20 wt% Pt/C, as well as being highly stable and well resistant to methanol.