Phase Evolution on the Hydrogen Adsorption Kinetics of NiFe‐Based Heterogeneous Catalysts for Efficient Water Electrolysis.

Transition metal layered double hydroxides, especially nickel‐iron layered double hydroxide (NiFe‐LDH) shows significant advancement as efficient oxygen evolution reaction (OER) electrocatalyst but also plays a momentous role as a precursor for NiFe‐based hydrogen evolution reaction (HER) catalysts. Herein, a simple strategy for developing Ni‐Fe‐derivative electrocatalysts via phase evolution of NiFe‐LDH under controllable annealing temperatures in an argon atmosphere is reported. The optimized catalyst annealed at 340 oC (denoted NiO/FeNi3) exhibits superior HER properties with an ultralow overpotential of 16 mV@10 mA cm−2. Density functional theory simulation and in situ Raman analyses reveal that the excellent HER properties of the NiO/FeNi3 can be attributed to the strong electronic interaction at the interface of the metallic FeNi3 and semiconducting NiO, which optimizes the H2O and H adsorption energies for efficient HER and OER catalytic processes. This work will provide rational insights into the subsequent development of related HER electrocatalysts and other corresponding compounds via LDH‐based precursors. [ABSTRACT FROM AUTHOR]