Unique Multi-Hetero-Interface Engineering of Fe-Doped Co-LDH@MoS 2 -Ni 3 S 2 Nanoflower-Based Electrocatalyst for Overall Water-Splitting: An Experimental and Theoretical Investigation.

Herein, a self-supported, robust, and noble-metal-free 3D hierarchical interface-rich Fe-doped Co-LDH@MoS 2 -Ni 3 S 2 /NF heterostructure electrocatalyst has been prepared through a controllable two-step hydrothermal process. The resultant electrode shows low overpotential of ~95 mV for hydrogen evolution reaction (HER), ~220 mV for the oxygen evolution reaction (OER), and the two-electrode system requires only a cell voltage of ~1.54 V at 10 mA cm -2 current density, respectively. Extensive ab initio calculations were carried out to find out the overpotential for HER, orbital interaction through the determination of electron density of states and quantification of charge transfer by Bader charge analysis. The computed overpotential matched closely with the experimental data. The superior HER performance of the tri-layer is enhanced due to the charge transfer (1.7444 e) to Fe-doped Co-LDH from Ni 3 S 2 -MoS 2 hybrid. This research strategy paves an effective pathway for affordable green H 2 production and future efficient non-precious bifunctional electrocatalyst design for overall water electrolysis.