Here, we report a novel Co/Co-Fe nanoparticle/N-doped carbon composite (Co/CoxFey/NC) obtained by thermal treatment of a composite of Co-Fe layered double hydroxide (Co-Fe LDH) and polybenzoxaxine (pBO) under ammonia atmosphere. The latter undergoes thermal degradation to form a conductive nitrogen-doped carbon matrix encapsulating Co/Co-Fe nanoparticles thereby circumventing the use of any binder material to immobilize the catalyst particles on the electrode surface.4 Within this work, the influence of the temperature, duration of treatment and the nature of gas atmosphere employed during the thermal treatment, as well as the ratio Co-Fe LDH:pBO on the electrocatalytic activity performance were investigated, leading to identification of an optimal Co/CoxFey/NC catalyst exhibiting remarkable bifunctional activity towards ORR and OER in 0.1 M KOH with an overpotential difference between these two reaction as low as 0.76 V at -1 mA cm-2 for the ORR and at 10 mA cm-2 for the OER, respectively. Moreover, the stability of Co/CoxFey/NC catalyst was evaluated in an air-breathing set-up, alternating between the OER and the ORR at a current density of 10 mA cm-2 in 6 M KOH to simulate the charge discharge cycles in rechargeable metal-air batteries for a total of 120 charge-discharge cycles each lasting 10 minutes.
References:
[1] Y. Li, H. Dai, Chem. Soc. Rev. 43 (2014) 5257-5275.
[2] J. Fu, Z.P. Cano, M.G. Park, A. Yu, M. Fowler, Z. Chen, Adv. Mater. 29 (2017) 1-34.
[3] J. Masa, W. Xia, I. Sinev, A. Zhao, Z. Sun, S. Grützke, P. Weide, M. Muhler, W. Schuhmann, Angew. Chem. Int. Ed. 53 (2014) 8508-8512.
[4] C. Andronescu, S. Barwe, E. Ventosa, J. Masa, E. Vasile, B. Konkena, S. Möller, W. Schuhmann, Angew. Chem. Int. Ed. 56 (2017) 11258-11262.