ZIF-8@ZIF-67 derived Fe–CoS2/CNT carbon polyhedron for enhanced electrocatalytic oxygen evolution reaction

Abstract

In the pursuit of highly active electrocatalysts is crucial to overcome the sluggish kinetics of oxygen evolution reaction (OER). Herein, Fe–CoS2/carbon nanotubes anchored on carbon polyhedron (Fe–CoS2/CNT CPs) is prepared by using zeolitic imidazolate framework-8@zeolitic imidazolate framework-67 (ZIF-8@ZIF-67) as template. A series of analysis demonstrates the incorporation of Fe via wrapped Fe-EDTA can exert charge transfer between Co and Fe and optimize the adsorption of targeted intermediates, which favors for enhanced OER performance. Moreover, the catalytic effect of Co and Fe not only promotes the growth of carbon nanotubes but also enhances the degree of graphitization. The carbon skeletons embedded with carbon nanotubes derived from ZIF-8@ZIF-67 offer high specific surface area and strengthen the electrical conductivity of Fe–CoS2/CNT CPs. Therefore, compared with its counterpart and commercial RuO2, the designed Fe–CoS2/CNT CPs with regulated electronic structure displays the lowest overpotential of 293 mV at the current density of 10 mA cm−2 in 1.0 M KOH solution for OER. This work explores a facile strategy for manipulate electronic structure and electrical conductivity of metal-organic frameworks derived catalysts simultaneously for robust OER electrocatalysts.