Metal‐organic framework‐derived Cu@Co4N nanoparticles anchored on N-doped carbon nanotubes for efficient and stable ORR activity

Abstract

Developing highly efficient, durable, and low-cost electrocatalysts for oxygen reduction reaction (ORR) is very important for energy conversion technologies. Electrocatalysts with porous structures, numerous active sites, and earth-abundant are exceedingly favorable for ORR reaction. In this work, the 3D nano hollow-shell Cu@Co4N anchored on N-doped carbon nanotubes (Cu@Co-N-C) was synthesized using pyrolyzed Cu@ZnCoZIF. The synthesized Cu@Co-N-C with bimetallic active sites, high specific surface area, high porosity structure, and nitrogen doping level demonstrates superior ORR activity. The physical characteristics of the cathode electrocatalysts were assessed through X-ray powder diffraction (XRD), scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET), Raman, and energy dispersive X-ray analysis (EDX) for elemental mapping. The electrocatalyst illustrates a higher half-wave potential of 0.88 V vs. RHE than that of the Pt/C electrocatalyst in an alkaline electrolyte. Moreover, it also has great ORR stability, making it one of the best Pt-free electrocatalysts. The current density of the Cu@Co-N-C is approximately -5.46 mA cm-2, which is higher than that of Co-N-C (-4.20 mA cm-2), and NCNTs (-1.9 mA cm-2). Moreover, higher stability was obtained for Cu@Co-N-C in comparison with Pt/C. So, this material is an excellent choice as a cathodic catalyst for application in metal-air fuel cells.

Keywords

• oxygen reduction reaction
• electrocatalyst
• metal-air battery
• m-n-c catalysts
• metal-organic frameworks