Surface Modification Effect on V-Doped Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub> as Bifunctional Catalyst Electrodes for Symmetric Supercapacitor and the Hydrogen Evolution Reaction
Jagadeesh Ramadoss, S. Arumugam, Mani Govindasamy
Abstract
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 Ti 3 C 2 T x material. KOH is used to alkalize Ti 3 C 2 T x, 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 Ti 3 C 2 T x 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 + –Ti 3 C 2 T x 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 + –Ti 3 C 2 T x 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 + –Ti 3 C 2 T x layered electrocatalyst doped with V (0.05) exhibits a low overpotential of 300 mV at 10 mA/cm 2 and low Tafel slope values of 105 mV dec –1 for the hydrogen evolution reaction in an acidic medium.