Trifunctional Co nanoparticle confined in defect-rich nitrogen-doped graphene for rechargeable Zn-air battery with a long lifetime

Rationally designing an efficient and stable multifunctional electrocatalyst to replace the noble metal catalysts is extremely demanding but challenging. Herein, we develop a facile method to synthesis the defective nitrogen-doped graphene encapsulated metal nanoparticles by pyrolysis of graphene-supermolecule complexes. The obtained catalyst exhibits superior activities toward ORR (E-1/2 = 0.864 V), OER (eta =383 mV@10 mA/cm(2)) and HER (eta = 193 mV@10 mA/cm(2)) in 0.1 M KOH solution. Equipping the materials into a rechargeable zinc-air battery produces a peak power density of 205 mW/cm(2) and a cycle life of 667 h. It is found that formative M-N-x and defective N-doped graphene are the main origins of ORR activity while OER and HER activities are attributed to the defect-rich N-doped C and Co core. This finding provides insights to design electrocatalyst with both multifunctional catalytic activities and high stability.

Automated summary

Rationally designing an efficient and stable multifunctional electrocatalyst to replace noble metal catalysts is challenging, but the newly developed method to synthesize metal nanoparticles enclosed in defective nitrogen-doped graphene has shown superior activities in various electrochemical reactions. This finding provides insights into designing electrocatalysts with high stability and multifunctional catalytic activities.