Interfacial Electronic Interactions Between Ultrathin NiFe-MOF Nanosheets and Ir Nanoparticles Heterojunctions Leading to Efficient Overall Water Splitting

Creating specific noble metal/metal-organic framework (MOF) heterojunction nanostructures represents an effective strategy to promote water electrolysis but remains rather challenging. Herein, a heterojunction electrocatalyst is developed by growing Ir nanoparticles on ultrathin NiFe-MOF nanosheets supported by nickel foam (NF) via a readily accessible solvothermal approach and subsequent redox strategy. Because of the electronic interactions between Ir nanoparticles and NiFe-MOF nanosheets, the optimized Ir@NiFe-MOF/NF catalyst exhibits exceptional bifunctional performance for the hydrogen evolution reaction (HER) (eta 10 = 15 mV, eta denotes the overpotential) and oxygen evolution reaction (OER) (eta 10 = 213 mV) in 1.0 m KOH solution, superior to commercial and recently reported electrocatalysts. Density functional theory calculations are used to further investigate the electronic interactions between Ir nanoparticles and NiFe-MOF nanosheets, shedding light on the mechanisms behind the enhanced HER and OER performance. This work details a promising approach for the design and development of efficient electrocatalysts for overall water splitting. A meticulously designed heterojunction bifunctional catalyst Ir@NiFe-MOF/NF, derived from anchoring Ir nanoparticles in NiFe-MOF/NF nanosheet arrays, exhibits a robust Ir & horbar;O & horbar;Ni/Fe interface interaction confirmed by XPS, Raman, and XAFS analyses. Such interaction augments H2O and intermediate adsorption, resulting in the superior HER and OER activities of the catalyst, which can serve as a promising bifunctional candidate for efficient electrocatalytic water splitting. image