Self-assemble strategy to fabricate multifunctional electrocatalyst for efficient and energy-saving water splitting

Abstract

It is a significant and challenging task to develop cheap, high-performance, and stable electrocatalysts for electrochemical water splitting. However, owing to the ponderous kinetics and high thermodynamic potential essential conditions of the anodic oxygen evolution reaction (OER), more energy is needed for the water splitting. Introducing more easily oxidized small molecules at the anode can achieve more energy-efficient electrochemical water hydrogen conversion. Herein, a high-capacity electrocatalyst (namely Co4S3/WC/Nb4C3Tx@NC) for water splitting was prepared by a simple way of mixing conductive particles of delaminated niobium carbide (Nb4C3Tx) MXene into transition metal sulfide/carbides. Meanwhile, the synergistic effect of Co4S3 and WC nanoparticles can enhance the activity of a single component and optimize the adsorption of hydrazine. The carbon layer can provide protection for the catalyst, and the addition of Nb4C3Tx MXene can improve the conductivity of the catalyst and provide more adsorption active sites. As a result, Co4S3/WC/Nb4C3Tx@NC catalyst presents a noteworthy activity and long-life durability with a lower overpotential of 84 or -66 mV to obtain 10 mA cm−2 for HER or hydrazine oxidation reaction (HzOR) in 1.0 M KOH, respectively. As expected, the dual electrode hydrazine-assisted electrolyzer by using the Co4S3/WC/Nb4C3Tx@NC as a multifunctional catalyst, generation of hydrogen can be easily realized at a much lower voltage (0.211 V@10 mA cm−2), which is much convenient than that of classical water splitting. Our work proposes an efficient and energy-saving MXene-based electrocatalyst for electrochemical water splitting.