Thermally stable cobalt amide cyanide as high-activity and durable bifunctional electrocatalyst toward O2 and CO2 reduction.

The electrocatalytic oxygen reduction reaction (ORR) and carbon dioxide reduction reaction (CO 2 RR) are considered as major strides for the development of a global-scale sustainable energy system, owing to their potential in neutralizing carbon emissions, generating value-added product, and delivering clean energy. However, the practicability of ORR and CO 2 RR is hampered by the sluggish kinetics and instability of the catalyst materials, calling for thirst for exploring efficient and stable electrocatalyst. With this concern, we herein report a hybrid (c-CoACC/CNTs) with carbon nanotubes (CNTs) decorating cubic cobalt amide cyanide complex (c-CoACC), which is synthesized by using molten salt (MS) assisted method and exhibits highly crystalline and thermally stable features. The c-CoACC/CNTs exhibit profound ORR activity with the onset and half-wave potential (E 1/2) of 0.972 and 0.87 V in alkaline conditions, respectively. The practical application of c-CoACC/CNTs as ORR catalysts has been verified in a home-made zinc-air battery, which is capable of releasing a maximum power density of 188 mW cm−2 in comparison with 175 mW cm−2 in the Pt/C based zinc-air battery. Furthermore, the c-CoACC/CNTs exhibits desirable electrocatalytic properties toward CO 2 -to-CO conversion in 0.5 M KHCO 3 with a tunable production ratio between CO and H 2 , yielding a maximum Faraday efficiency of 83.8% at −0.78 V vs. RHE. The attractive electrocatalytic properties in the c-CoACC/CNTs can be attributed to the improved electroactive sites relative to individual c-CoACC and CNT, reduced diffusion resistance, and enhanced three-phase boundaries. Notably, the c-CoACC/CNTs perform encouraging stability in the catalysis of ORR and CO 2 RR under various electrochemical regimes and conditions, directing a viable path for a future global-scale sustainable energy system. [ABSTRACT FROM AUTHOR]