Copper-Decorated Ti₃C₂T_x MXene Electrocatalyst for Hydrogen Evolution Reaction

Abstract

It remains a formidable challenge to prepare an economical and stable electrocatalyst for hydrogen evolution reaction using non-precious metals. In this study, MXene (Ti3C2Tx) nanosheets were prepared by high-energy ultrasound treatment, and Cu nanoparticles were prepared by NaBH4 as a reducing agent. Then, the electrocatalyst Cu/Ti3C2Tx, suitable for hydrogen evolution reaction (HER), was prepared by supporting Cu with Ti3C2Tx. The structure, morphology, crystal phase and valence state of the obtained catalyst were determined by a variety of characterization analysis methods, and the influence of these properties on the catalytic performance is discussed here. The results of Brunner–Emmet–Teller (BET) showed that Ti3C2Tx can effectively inhibit Cu agglomeration. Results of Transmission Electron Microscopy (TEM) and X-ray Diffraction (XRD) showed that Cu has metallic and oxidized states. X-ray Photoelectron Spectroscopy (XPS) further revealed the existence of multivalent states in Cu, which would contribute to the formation of electron transfer channels and the enhancement of electrocatalytic activity. In addition, the Cu/Ti3C2Tx catalyst has strong hydrophilicity, as measured by contact angle, which is conducive to HER. Ti3C2Tx has acceptable electrocatalytic hydrogen evolution performance: under alkaline conditions, when the current density is 10 mA cm−2, HER overpotential is as low as 128 mV and the Tafel slope is as low as 126 mV dec−1. Meanwhile, Ti3C2Tx showed adequate stability for HER (94.0% of the initial mass activity after 1000 CV cycles). This work offers insights into the development of high-performance non-precious metal-based catalysts to achieve the high performance of HER in alkaline electrolytes.

Keywords

• hydrogen evolution reaction
• electrocatalyst
• Cu
• MXene (Ti₃C₂T_x) nanosheets