Nanocomposite engineering: Tailoring MXene/Cobalt oxide for efficient electrocatalytic hydrogen and oxygen evolution reactions

Abstract

Electrocatalytic water splitting has become a significant method of hydrogen production to overcome the energy scarcity and increased rate of pollution caused by the extreme consumption of fossil fuels. Pure cobalt oxide is a potential option for electrocatalytic water splitting due to its higher OER activity but lacks stability, conductivity, and active sites which impair its electrocatalytic performance. In this study, Ti3C2Tx/Co3O4 nanocomposite is synthesized to address the previously noted difficulties along with detailed study of both combinations in three different ratios (1:1, 1:2, 2:1). The outcomes demonstrated that the combination of Ti3C2Tx and Co3O4 in the ratio 1:2 outperformed the component materials in terms of electrocatalytic activity with the lowest overpotential of 270 mV at 50 mA cm‐2−2 for the oxygen evolution reaction (OER), having the least Tafel slope (85 mV dec−1) and Ti3C2Tx/Co3O4 in the ratio 2:1 showed overpotential of 235 mA cm−2, with lowest Tafel slope of 97 mV dec−1 which is the lowest among all electrodes for hydrogen evolution reaction (HER). In Ti3C2Tx MXene with increased O functional group providing adsorption site for hydrogen enables HER in a faster rate. While cobalt oxide enables charge transfer to electronegative MXene which in turn result in stability of the electrocatalyst. In the case of OER, Ti3C2Tx/Co3O4 (1:2) shows the better performance as Co centres act as the active sites for OER while MXene has the role of support matrix for the Co3O4 nanoparticles and prevent aggregation. By choosing these two particular composites, Ti3C2Tx/Co3O4 (2:1) as cathode and Ti3C2Tx/Co3O4 (1:2) as anode overall water splitting was done. For total electrolysis, a potential of 1.73 V was required to provide a current density of 10 mA cm−2 with satisfactory stability. Thus, the produced material is a promising contender for producing green hydrogen in the future.