Bimetallic metal-organic framework derived doped carbon nanostructures as high-performance electrocatalyst towards oxygen reactions

Rational design and development of cost-effective, highly active and durable bifunctional electrocatalysts towards oxygen redox reactions is of critical importance but great challenge for the broad implementation of next-generation metal-air batteries for electric transportation. Herein, a high-performance electrocatalyst of cobalt and zinc sulfides nanocrystals embedded within nitrogen and sulfur co-doped porous carbon is successfully designed and derived from bimetallic metal-organic frameworks of cobalt and zinc containing zeolitic imidazolate frameworks. The unique nanostructure contains abundant electrocatalytic active sites of sulfides nanocrystals and nitrogen and sulfur dopants which can be fast accessed through highly porous structure originate from both zinc vaporization and sulfurization processes. Such bifunctional electrocatalyst delivers a superior half-wave potential of 0.86 V towards oxygen reduction reaction and overpotential of 350 mV towards oxygen evolution reaction, as well as excellent durability owing to the highly stable carbon framework with a great graphitized portion. The performance boosting is mainly attributed to the unique nanostructure where bimetallic cobalt and zinc provide synergistic effect during both synthesis and catalysis processes. The design and realization pave a new way of development and understanding of bifunctional electrocatalyst towards clean electrochemical energy technologies.