ß-Cyclodextrin-Stabilized CuO/MXene Nanocomposite as an Electrode Material for High-Performance Supercapacitors.

Supercapacitors are the best energy storage systems due to their high power density, quick charge/discharge rate, and long-term reliability. In this study, ß-cyclodextrin-stabilized CuO nanoparticles (CuO@ßCD NPs) were synthesized through a simple reduction method and anchored on the surface of MXene nanosheets in three different proportions (1:1, 4:1, and 1:4) to obtain CuO@ßCD/MXene nanocomposites through the wet-impregnation method. The formation of CuO@ßCD NPs and their physicochemical characteristics were verified by XRD, XPS, FE-SEM, and HR-TEM analysis. The actual focus is on the evaluation of the electrochemical performances of CuO@ßCD, MXene, and CuO@ßCD/MXene nanocomposites for supercapacitor applications. The cyclic voltammetry and galvanostatic charge-discharge analysis revealed the pseudocapacitance and an improved specific capacitance of 1693.43 F g-1 at 0.90 A g-1 for the CuO@ßCD/MXene (1:1) nanocomposite. The electrochemical impedance analysis displays superior electrical conductivity with a low charge transfer resistance value on incorporating CuO@ßCD between the MXene layers. Furthermore, the CuO@ßCD/MXene (1:1) nanocomposite exhibited improved long-term cycling stability by retaining 86% of its initial specific capacitance even after the 10,000th cycle at the current density of 4.54 A g-1. Based on the electrochemical performance, the CuO@ßCD/MXene (1:1) nanocomposite proves its suitability as an electrode material for supercapacitor application with long-term cycling stability and rate capability.

Flower-like Layered NiCu-LDH/MXene Nanocomposites as an Anodic Material for Electrocatalytic Oxidation of Methanol.

Direct methanol fuel cell (DMFC) technology has grabbed much attention from researchers worldwide in the realm of green and renewable energy-generating technologies. Practical applications of DMFCs are marked by the development of highly active, efficient, economical, and long-lasting anode catalysts. Layered double hydroxide (LDH) nanohybrids are found to be efficient electrode materials for methanol oxidation. In this study, we synthesized NiCu-LDH/MXene nanocomposites (NCMs) and investigated their electrochemical performance for methanol oxidation. The formation of NCM was verified through field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Brunauer-Emmett-Teller (BET), and X-ray photoemission spectroscopy (XPS) analyses. The cyclic voltammetry, chronoamperometry, and electron impedance spectroscopy techniques were carried out to assess the electrocatalytic ability of the methanol oxidation reaction. The incorporation of MXene enhanced the methanol oxidation 2-fold times higher than NiCu-LDH. NCM-45 exhibited high peak current density (86.9 mA cm-2), enhanced electrochemical active surface area (7.625 cm2), and long-term stability (77.8% retention after 500 cycles). The superior performance of NCM can be attributed to the synergistic effect between Ni and Cu and, further, the electronic coupling between LDH and MXene. Based on the results, NCM nanocomposite is an efficient anodic material for the electrocatalytic oxidation of methanol. This study will open the door for the development of various LDH/MXene nanocomposite electrode materials for the application of direct methanol fuel cells.