Rational Design of Dynamic Bimetallic NiCoSe2/2D Ti3C2Tx MXene Hybrids for a High-Performance Flexible Supercapacitor and Hydrogen Evolution Reaction

Herein, intelligent construction of an NiCoSe 2 /Ti 3 C 2 T x hybrid heterostructure with unique morphologies was performed using a hydrothermal protocol. The coexistence of the dual metal core in Ni–Co selenides and Ti 3 C 2 T x MXene helps in realizing outclassing physicochemical properties. The two-dimensional (2D) heterostructure provides an admirably smaller Tafel slope of 86 mV/dec, indicating the faster H 2 evolution rate (Pt/C: 82 mV/dec) and overpotential of 62 mV at 10 mA/cm 2 (Pt/C: 52 mV/dec). Our heterostructure devices demonstrate a specific energy density of 32.05 Wh kg –1 coupled with a power density of 0.2 kW kg –1 and maintain 15.39 Wh kg –1 coupled with a power density of 0.92 kW kg –1 . The experimental results underpin new profitable opportunities and scale up deployment of the bifunctional electrodes. Further, the experimental findings were supported through density functional theory (DFT) simulations in terms of a lower overpotential and higher quantum capacitance for the heterostructure NiCoSe 2 /MXene compared to pristine NiCoSe 2 . There is charge transfer from MXene Ti 3 C 2 T x to NiCoSe 2 leading to enhanced electronic states near the Fermi level responsible for enhanced catalytic activities and charge storage performance.