Boosting the oxygen electrode reaction performance of porous carbon derived composites via extracting encapsulated Co nanoparticles by in-situ catalyzed carbon nanotubes

Abstract

Porous carbon has been extensively adopted to construct composite electrocatalysts by virtue of its three dimensional (3D) porous structure and massive edge sites. However, it is challengeable to maintain their catalytic activity due to the buried active sites within stacked carbon layers. Here we report a facile strategy via extracting cobalt (Co) within the carbon layers via catalyzing growth of nitrogen-doped carbon nanotube (NCNT). The Co-catalyzed NCNTs from the debris of decomposed melamine not only extract the Co nanoparticles into the tube, but also suppresses the chemical/thermal coarsening of Co nanoparticles, and thus promote the metal-support interaction. Moreover, the entangled NCNTs bridge over the porous carbon, modulating the porosity and mass transfer of porous carbon. As a result, the obtained Co@NCNT-PC exhibits enhanced stability and optimized catalytic activity towards oxygen reduction reaction (ORR) with the half-wave potential positively shift around 30 mV when compared with that of Co@NCNT-PC-NM. In addition, Co@NCNT-PC based Zinc-air battery delivers a power density of 146 mW cm−2, which is 2-fold higher than that assembled using commercial electrocatalysts. Therefore, this work provides an applicable strategy for optimizing the performance of porous carbon derived hybrid electrocatalysts.