The 3D porous “celosia” heterogeneous interface engineering of layered double hydroxide and P-doped molybdenum oxide on MXene promotes overall water-splitting

Exploiting efficient and economical electrocatalysts is indispensable for promoting the sluggish kinetics of overall water-splitting. Herein, we ingeniously designed a simple one-pot hydrothermal method to construct a 3D porous "celosia-like" heterogeneous framework of FeCo-layered double hydroxide (FeCo-LDH) and P-doped molybdenum oxide (P-MoO3) grown in-situ on MXene-modified nickel foam substrate (denoted as P-MoO3 FCL MXene/NF), with high conductivity, highly hydrophilic properties, and favorable kinetics. Density functional theory calculations (DFT) demonstrate that the electronic engineering tuning of electron dissipation and aggregation at the heterogeneous interface of P-MoO3 and FeCo-LDH optimizes the electron transfer rate of the active site and the d-band center near the Fermi level, thereby reducing the adsorption energy of H and O reaction intermediates (H*, OH*, OOH*) and improves the intrinsic catalytic activity. As expected, benefiting from the strong chemical and electron synergistic effect between heterogeneous structures, the synthesized P-MoO3 FCL MXene/NF heterogeneous framework exhibits excellent activity for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) with a low overpotential of 179 mV and 118 mV at 10 mA cm−2, respectively, and Faraday efficiency of up to 96 %. Significantly, the overpotential of 1.53 V is enough to drive a current density of 10 mA cm−2 in a two-electrode configuration which is greatly superior to other bifunctional electrocatalysts.