Two-dimensional (2D) surface-terminated layered transition metal carbide MXenes with high electrochemical performance paved the way for robust energy storage supercapacitor devices. However, because of the 2D nature of the MXene flakes, self-restacking of 2D MXene flakes limits the use of all the flake functionalized surfaces in MXene electrodes. Here, we report the synthesis of V2CT x MXene and multiwall carbon nanotube (MWCNT)/V2CT x composites as a promising electrode material for hybrid energy storage devices. Our hybrid electrodes exhibited enhanced electrochemical performance and a gravimetric capacitance of 1842 F g−1 at a scan rate of 2 mV s−1, with a specific charge capacity of 62.5 A h/g. Moreover, the electrodes presented an excellent rate performance, durability, and retention capacity of 94% lasted up to 10 000 cycles. Density functional theory calculations provided electronic and structural properties of the considered MWCNT@V2CT x. Therefore, the introduction of MWCNTs enhanced the conductivity and reaction kinetics of the MXenes and facilitates the charge storage mechanism useful for next-generation smart energy storage devices.

Utilization of cost-effective, bifunctional, and efficient electrocatalysts for complete water splitting is desirable for sustainable clean hydrogen energy.

Two-dimensional (2D) MXenes and their composites are increasingly performing as efficient catalysts for the production of hydrogen (H2) and oxygen (O2). Herein, we report a strategy for the surface modification of V2CT x MXene as an efficient bifunctional hybrid electrocatalyst for water splitting application by optimized loading of spherical silver nanoparticles (Ag-NPs) on V2CT x nanosheets (NSs). In 1.0 M KOH solution, the V2CT x /Ag-NPs nanohybrid (labeled as HII) attained an overpotential of 310 mV (vs RHE) and a Tafel slope of 62 mV/dec for the oxygen evolution reaction (OER), and an overpotential of 32 mV (vs RHE) and a Tafel slope of 114 mV/dec for the hydrogen evolution reaction (HER). The hybrid showed significantly improved values than those of their constituents (MXene nanosheets and Ag-NPs) and was even comparable to the industrial RuO2 and Pt electrocatalysts. The uniform loading of silver nanoparticles (Ag-NPs) on 2D MXene sheets acted as a conductive agent and their large surface area facilitated ion transport by ensuring short conductive pathways at the electrode–electrolyte interface. Moreover, the strong contact and electrical coupling with charge transfer between Ag-NPs and V2CT x MXene provided much higher water-splitting performance and structural stability as well as low charge transfer resistance, which eventually enhanced the intrinsic activity of the catalyst. This HER reaction followed the Volmer–Heyrovsky mechanism for H2 production at the cathode. The dispersion of Ag-NPs increases the Raman signals of V2CT x for the hybrid, demonstrating the surface-enhanced activity of Raman scattering. The three-dimensional frame structure of nickel foam helped in easing the release of oxygen and hydrogen gas bubbles from the reaction sites.