An Efficient and Stable MXene-Immobilized, Cobalt-Based Catalyst for Hydrogen Evolution Reaction

Hydrogen (H2) is considered to be the best carbon-free energy carrier that can replace fossil fuels because of its high energy density and the advantages of not producing greenhouse gases and air pollutants. As a green and sustainable method for hydrogen production, the electrochemical hydrogen evolution reaction (HER) has received widespread attention. Currently, it is a great challenge to prepare economically stable electrocatalysts for the HER using non-precious metals. In this study, a Co/Co3O4/Ti3C2Txcatalyst was synthesized by supporting Co/Co3O4with Ti3C2Tx. The results show that Co/Co3O4/Ti3C2Txhas excellent HER activity and durability in 1 mol L−1KOH, and the overpotential and Tafel slope at 10 mA·cm−2were 87 mV and 61.90 mV dec−1, respectively. The excellent HER activity and stability of Co/Co3O4/Ti3C2Txcan be explained as follows: Ti3C2Txprovides a stable skeleton and a large number of attachment sites for Co/Co3O4, thus exposing more active sites; the unique two-dimensional structure of Ti3C2Txprovides an efficient conductive network for rapid electron transfer between the electrolyte and the catalyst during electrocatalysis; Co3O4makes the Co/Co3O4/Ti3C2Txcatalyst more hydrophilic, which can accelerate the release rate of bubbles; Co/Co3O4can accelerate the adsorption and deionization of H2O to synthesize H2. This study provides a new approach for the design and preparation of low-cost and high-performance HER catalysts.