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 molybde-num 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 het-erogeneous 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.

Automated summary

In this study, a simple one-pot hydrothermal method was used to construct a highly conductive and hydrophilic 3D porous celosia-like heterogeneous framework. The framework exhibited excellent activity in oxygen and hydrogen evolution reactions. Density functional theory calculations showed that the framework could optimize electron transfer rate and improve the adsorption energy of active sites, thereby enhancing its catalytic activity.