Construction of Co/Co2N0.67 nanoparticles embedded S and N-doped carbon from a cobalt-complex as a bifunctional Electrocatalyst for ORR and OER

Advancing impactful, economical, and durable Co-based bifunctional electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) has been crucial in developing sustainable energy technologies. In this work, Co and Co₂N_0.67 nanoparticles (NPs)-incorporated S, N-doped carbon catalysts (Co/Co₂N_0.67/SNC) were prepared via direct pyrolysis of the CoDATT complex, exhibiting high bifunctional electrocatalytic performance for ORR and OER. The complex precursor, CoDATT, was synthesized for the first time using diaminoterthiophene (DATT) and CoCl₂. The complex was directly pyrolyzed at 800 °C, followed by an acid wash to obtain the catalyst Co/Co₂N_0.67/SNC. The optimized catalyst displayed a low OER overpotential (η = 331 mV vs. reversible hydrogen electrode (RHE) at 10 mA cm^-2), an excellent ORR half-wave potential (E_1/2 = 0.878 V vs. RHE), high stability, and alcohol tolerance as a bifunctional OER and ORR electrocatalyst, surpassing the activity of the benchmarks RuO₂ and Pt/C, respectively, in an alkaline medium. The high catalytic activity of the optimized catalysts can be attributed to the S, N-co-doping, as well as the synergistic effect between Co/Co₂N_0.67 NPs and SNC, resulting in enhanced catalytic performance for both ORR and OER.