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 NiCoSe2/Ti3C2Tx hybrid hetero-structure with unique morphologies was performed using a hydrothermal protocol. The coexistence of the dual metal core in Ni-Co selenides and Ti3C2Tx MXene helps in realizing outclassing physicochemical properties. The two-dimensional (2D) hetero-structure provides an admirably smaller Tafel slope of 86 mV/dec, indicating the faster H2 evolution rate (Pt/C: 82 mV/dec) and overpotential of 62 mV at 10 mA/cm2 (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 NiCoSe2/MXene compared to pristine NiCoSe2. There is charge transfer from MXene Ti3C2Tx to NiCoSe2 leading to enhanced electronic states near the Fermi level responsible for enhanced catalytic activities and charge storage performance.