Synergistic interface engineering of nickel-iron layered double hydroxide/metal-organic framework heterostructure as superior bifunctional electrocatalyst for overall water splitting

Advancing high-performance and durable bifunctional electrocatalysts capable of mutually driving oxygen/hydrogen evolution reaction (OER/HER) represents pivotal step towards sustainable hydrogen production. This study proposes an innovative three-dimensional porous heterostructure catalyst (NiFe-LDH/MOF/NFF) by encapsulating NiFe-metal organic framework (NiFe-MOF) on nickel-iron foam (NFF) with NiFe-layered double hydroxide (NiFe-LDH) nanosheets via a continuous solvothermal-hydrothermal method. The resulting heterostructure exhibits abundant interfaces with more exposed active sites and optimized electronic configurations, where the enhanced interfacial charge transfer facilitates to enhance bifunctional catalytic performance in alkaline media. The catalyst establishes exceptional OER property with low overpotentials for OER ( η 10  = 190 mV, η 100  = 204 mV and η 500  = 237 mV) and HER ( η 10  = 98 mV). DFT calculations elucidate that the superior performance stems from the LDH/MOF interfacial electron redistribution, synergistic Ni-Fe site interactions and optimized adsorption energetics to reaction intermediates. When employed as an overall water splitting system, it merely requires low voltages of 1.527 and 1.687 V to drive 10 and 100 mA cm −2 with a robust stability for over 120 h. It highlights great potential in alkaline freshwater and simulated seawater electrolysis applications. The interfacial electronic modulation provides a valuable guidance for rational designing electrocatalysts for future energy conversion applications.