NiFe-Layered Double Hydroxide Synchronously Activated by Heterojunctions and Vacancies for the Oxygen Evolution...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Commercial hydrogen production relies on efficient electrocatalysts for water splitting.
• Earth-abundant transition metals are sought for cost-effective electrocatalyst development.
• Bifunctional electrocatalysts capable of both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are crucial.

Purpose of the Study:

• To develop novel earth-abundant transition-metal-based electrocatalysts with bifunctional OER/HER properties.
• To construct layered double hydroxide (LDH)-zinc oxide (ZnO) heterostructures with oxygen vacancies.
• To investigate the impact of ZnO deposition on the catalytic activity and active sites of NiFe-LDH.

Main Methods:

• Plasma magnetron sputtering of NiFe-LDH on Ni foam to create nanoflower structures.
• Synchronous construction of LDH-ZnO heterostructures and oxygen vacancies.
• Theoretical assessment using computational methods to confirm active site changes and charge transfer.

Main Results:

• Uniform distribution of ZnO nanoparticles on NiFe-LDH nanoflowers.
• Evidence of electron depletion at Ni cations and active site shift from Fe to Ni during OER.
• Achieved overall water splitting at 1.603 V in 1 M KOH using Ni/LDH-ZnO as anode and Ni/LDH as cathode.

Conclusions:

• A novel design for self-supported catalytic electrodes for efficient water splitting was revealed.
• Surface modification of catalytic materials through heterostructure formation and oxygen vacancies enhances performance.
• The developed electrocatalysts show significant promise for commercial hydrogen production.