In-situ growth and performance of transition metal doped CNT/N-graphene composites

Abstract

The direct pyrolysis method was adopted with graphene as the carrier, 2-methylimidazole zinc salt MAF-4(ZIF8) and urea to provide carbon and nitrogen sources, Fe as the transition metal source, to synthesize nitrogen-doped graphene(N/GO) and Fe-ZIF8(N-GO@Fe/ZIF8) composite catalyst, assembled into a zinc-air battery. The physical-chemical properties of the catalyst were characterized by using scanning electron microscope(SEM), transmission electron microscope(TEM) and rotating disk electrode. The results show that the synthesized N-GO@Fe/ZIF8-900 catalyst has excellent oxygen reduction/oxygen evolution (ORR/OER) performance. The half wave potential is 0.885 V, which is better than that of Pt/C (0.856 V). When oxygen is precipitated, the corresponding potential is 1.811 V at a current density of 10 mA/cm2, which is better than that of the noble metal Pt/C (1.968 V) and the same performance as IrO2 (1.75 V).After being assembled into a zinc air battery, the specific energy and power density reach 886.2 mW·h·g-1 and 73.44 mW/cm2 respectively, which are higher than that of Pt/C (791.04 mW·h·g-1, 57.12 mW/cm2) respectively. The catalyst has good application prospect.

Keywords

• zif8
• carbon nanotubes
• in-situ growth
• zinc air battery