Universal avenue to metal-transition metal carbide grafted N-doped carbon framework as efficient dual Mott-Schottky electrocatalysts for water splitting

Abstract

Transition metal carbides (TMCs) have gained considerable attention as a non-precious multifunctional, highly active, stable electrocatalyst for efficient hydrogen evolution reaction (HER) due to its platinum like d-band electronic structure. The efforts to untie the gordian knot of developing a first-rate bifunctional electrocatalyst for efficient water splitting reaction via electronically modulated bimetallic carbides using a dual transition metal strategy have been reported here. Herein we in-situ fabricated a composite architecture consisting of N-doped CNT/ graphene hybrid anchoring Co/MoC, Co/WC and Co/VC Via an integrated pyrolysis technique to have a beneficial synergistic co-operation between each component and dual Mott-Schottky junctions resulting in a bifunctional HER and OER (oxygen evolution reaction) active catalyst exhibiting exemplary activity in both acidic and basic media. Co/MoC@NC exhibits the best activity with a lower overpotential of 279 and 260 mV towards OER and 92 and 143 mV towards HER to achieve a current density of 10 mA/cm2 in basic and acidic media, respectively. Along with this, it presents excellent water splitting performance in basic media, showing a relatively low cell voltage of about 1.686 V for driving a current of 10 mA/cm2 with decent stability. It is anticipated that the tandem electron transfer between the Co, MoC moieties and nitrogen doping-induced defects in graphene/ CNT hybrid-based conductive network support might be a reason for the superiority over other recently reported Mo based carbide materials.