Anthocephalus cadamba shaped FeNi encapsulated carbon nanostructures for metal-air batteries as a resilient bifunctional oxygen electrocatalyst

Abstract

Anthocephalus cadamba shaped carbon nanostructures comprising FeNi encapsulated in radially grown nitrogen-doped carbon nanotubes (NCNTs) are produced by controlled pyrolysis which exhibit advanced electrochemical oxygen evolution reaction (OER) performance with a low overpotential of similar to 290 mV at 10 mA cm(-2), small Tafel slope (37 mV dec(-1)) and endurance in an accelerated stability test. In addition to better surface electron transfer kinetics, the radial growth of NCNTs offers plenty of electrochemically active sites (high roughness factor similar to 340) in tiny spaces, better accessibility to reactant species and appropriate gas outlets to prevent bubble accumulation during OER. Besides OER, the preferential 4e(-) pathways for the oxygen reduction reaction (ORR) and excellent overall oxygen electrochemistry Delta E (E-j(OER)=10 - E-1/2(ORR) = 0.71 V) suggest excellent bifunctionality and advocate the practical importance of Anthocephalus cadamba shaped carbon nanostructures as a possible unitary oxygen electrocatalyst for metal-air battery systems