Hierarchically integrated NiFe LDH/Ni3S2 on Ni foam as a highly efficient electrocatalyst for alkaline oxygen evolution
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In this work, a hierarchical NiFe-LDH/Ni3S2@Ni-foam heterostructure was rationally constructed on conductive Ni foam viaa two-step hydrothermal strategy and evaluated as an efficient oxygen evolution reaction (OER) electrocatalyst. Thioureaassistedsulfurization of Ni foam produced vertically aligned Ni3S2 nanosheets, which served as a highly conductive and porousscaffold. Subsequent hydrothermal growth of NiFe layered double hydroxide (LDH) nanosheets on the Ni3S2 surface resultedin an intimately coupled NiFe-LDH/Ni3S2@Ni-foam nanoarchitecture. X-ray diffraction and FE-SEM analyses confirmed thesuccessful formation of both Ni3S2 and NiFe-LDH phases and revealed a well-defined hierarchical nanosheet network. XPSfurther demonstrated the coexistence of Ni²⁺ and Fe³⁺ species and suggested strong interfacial electronic coupling betweenNiFe-LDH and Ni3S2. Benefiting from the synergistic combination of the conductive Ni₃S₂ backbone and the highly active NiFe-LDH nanosheets, the NiFe-LDH/Ni₃S₂@Ni-foam electrode exhibited superior OER performance, delivering overpotentials of315 and 325 mV at 50 and 100 mA·cm-2, respectively, along with a low Tafel slope of 72 mV·dec⁻¹, thereby outperformingboth Ni₃S₂@Ni-foam and NiFe-LDH@Ni-foam. Electrochemical impedance spectroscopy and ECSA analysis further revealedreduced charge-transfer resistance and significantly increased active surface area for the heterostructured sample. This studyprovides a simple and effective strategy for designing high-performance OER electrocatalysts via interfacial engineering ofsulfide and LDH nanostructures.
Abstract
In this work, a hierarchical NiFe-LDH/Ni3S2@Ni-foam heterostructure was rationally constructed on conductive Ni foam viaa two-step hydrothermal strategy and evaluated as an efficient oxygen evolution reaction (OER) electrocatalyst. Thioureaassistedsulfurization of Ni foam produced vertically aligned Ni3S2 nanosheets, which served as a highly conductive and porousscaffold. Subsequent hydrothermal growth of NiFe layered double hydroxide (LDH) nanosheets on the Ni3S2 surface resultedin an intimately coupled NiFe-LDH/Ni3S2@Ni-foam nanoarchitecture. X-ray diffraction and FE-SEM analyses confirmed thesuccessful formation of both Ni3S2 and NiFe-LDH phases and revealed a well-defined hierarchical nanosheet network. XPSfurther demonstrated the coexistence of Ni²⁺ and Fe³⁺ species and suggested strong interfacial electronic coupling betweenNiFe-LDH and Ni3S2. Benefiting from the synergistic combination of the conductive Ni₃S₂ backbone and the highly active NiFe-LDH nanosheets, the NiFe-LDH/Ni₃S₂@Ni-foam electrode exhibited superior OER performance, delivering overpotentials of315 and 325 mV at 50 and 100 mA·cm-2, respectively, along with a low Tafel slope of 72 mV·dec⁻¹, thereby outperformingboth Ni₃S₂@Ni-foam and NiFe-LDH@Ni-foam. Electrochemical impedance spectroscopy and ECSA analysis further revealedreduced charge-transfer resistance and significantly increased active surface area for the heterostructured sample. This studyprovides a simple and effective strategy for designing high-performance OER electrocatalysts via interfacial engineering ofsulfide and LDH nanostructures.