Ni-O₄ as Active Sites for Efficient Oxygen Evolution Reaction with Electronic Metal-Support Interactions

Area of Science:

• Catalysis
• Materials Science
• Electrochemistry

Background:

• Single-atom catalysts (SACs) are crucial for efficient electrocatalysis.
• Optimizing the metal site structure is key for enhancing the oxygen evolution reaction (OER).

Purpose of the Study:

• To synthesize and investigate oxygen-doped nickel SACs anchored on porous carbon (Ni-O-G).
• To explore the Ni-O4 active sites for improved OER performance.
• To understand the electronic effects of Ni-O4 coordination on OER kinetics.

Main Methods:

• Synthesis of Ni-O-G using molten salts (ZnCl2 and NaCl) as templates.
• Electrocatalytic testing for OER performance evaluation.
• Characterization techniques and density functional theory (DFT) calculations.

Main Results:

• Achieved an overpotential of 238 mV at 10 mA cm-2 for Ni-O-G, demonstrating advanced OER activity.
• Identified the unique Ni-O4 structure as the active site.
• DFT calculations revealed enhanced metal-support interaction due to Ni-O4 coordination.

Conclusions:

• The Ni-O4 coordination facilitates OER kinetics by bringing Ni closer to the Fermi level.
• This study presents a novel strategy for modulating Ni SACs structure and improving OER activity.
• Highlights the impact of coordination elements on intrinsic OER activity.