Synergistically coupling of Co/Mo2C/Co6Mo6C2@C electrocatalyst for overall water splitting: The role of carbon precursors in structural engineering and catalytic activity

Abstract

It is essential to optimize the surface functional properties of nanomaterials, which significantly impact catalytic performance. Until now, less work has been reported on tuning the structural interface configurations utilizing various carbon precursors to enhance catalytic activity toward overall water splitting. Herein, a facile one-pot pyrolysis strategy is developed to prepare the metallic cobalt with molybdenum carbide nanoparticles enclosed in porous carbon nanosheets heterostructure (Co/Mo2C/Co6Mo6C2@C) using different carbon sources, namely salicylic acid, phthalic acid, sodium tartrate, and fumaric acid. The optimum catalyst (CMC/750SA) exhibits a low overpotential of 138 and 281 mV @10 mA cm−2 of current density for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in 1.0 M KOH, respectively. Also, the CMC/750SA catalyst exhibits outstanding activity toward HER with a low overpotential of 118 mV@10 mA cm−2 in acidic H2SO4 (0.5 M) solution and attains robust stability over 48 h. The two-electrode configuration utilizing CMC/750SA as cathode and anode required a cell voltage of 1.589 V@10 mA cm−2 in 1.0 M KOH. This work reveals that optimizing the interface structure engineering plays a crucial role in improving overall water splitting performance and helps to design an efficient carbon-based catalyst for extensive electrochemical applications.