Surface Modification Effect on V-Doped Ti3C2Tx as Bifunctional Catalyst Electrodes for Symmetric Supercapacitor and the Hydrogen Evolution Reaction

MXene-based composite materials have plenty of characteristics, such as high surface area, excellent metallic conductivity, rapid oxidation, and reduction activity. These materials have many advantages for use in modified electrodes for energy storage and conversion applications. However, their applicability in several types of industries has been significantly limited as a result of issues with surface aggregation and oxidation. In this study, we improved the electrochemical properties of the electrodes by modifying the surface of the layered Ti3C2Tx material. KOH is used to alkalize Ti3C2Tx, and −OH is replaced by F. The surface hydroxyl groups can be eliminated through intercalation with K+. This study reports on the synthesis of vanadium-doped layered Ti3C2Tx nanosheets intercalated with K+ using a hydrothermal synthesis method. The resulting material serves as a bifunctional catalyst for electrochemical supercapacitors and hydrogen evolution. The V (0.05)-doped K+–Ti3C2Tx electrodes demonstrated a superior specific capacitance of 670 F g–1 when an applied current of 1 A g–1 was used in the three-electrode system. The symmetric supercapacitor device was constructed using the V (0.05)-doped K+–Ti3C2Tx electrode, which delivered a high specific energy (110 Wh kg–1) and power density (1804.91 W kg–1). The symmetric capacitance of the electrode is 220.2 F g–1 at a current density of 1 A g–1, and it exhibits an admirable specific capacity retention of 97.8% after 10 000 cycles. Furthermore, the K+–Ti3C2Tx layered electrocatalyst doped with V (0.05) exhibits a low overpotential of 300 mV at 10 mA/cm2 and low Tafel slope values of 105 mV dec–1 for the hydrogen evolution reaction in an acidic medium.