Cobalt Intercalated Layered NiFe Double Hydroxides for the Oxygen Evolution Reaction

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Layered double hydroxides (LDHs) are promising electrocatalysts.
• Oxygen evolution reaction (OER) is crucial for energy conversion.
• NiFe LDHs show good OER activity but can be improved.

Purpose of the Study:

• To enhance the electrocatalytic activity of NiFe LDHs for OER.
• To investigate the effect of cobalt incorporation on NiFe LDH performance.
• To elucidate the mechanism behind the enhanced activity.

Main Methods:

• Combined experimental (electrochemical measurements) and theoretical (density functional theory) approaches.
• Synthesis of cobalt-modified NiFe LDHs via coprecipitation and/or intercalation.
• Electrocatalytic testing for OER at various cobalt loadings.

Main Results:

• Cobalt-modified NiFe LDHs exhibit enhanced OER activity compared to pristine NiFe LDHs.
• Overpotentials for Co-modified NiFe LDHs range from 290-322 mV.
• The best catalyst, cobalt intercalated NiFe LDH, achieved an overpotential of ~265 mV at 10 mA cm^-2 with 99% Faradaic efficiency and long-term stability.
• DFT calculations confirmed cobalt's role in tuning electronic structure for optimal intermediate binding.

Conclusions:

• Systematic cobalt incorporation is an effective strategy to enhance NiFe LDH electrocatalytic activity for OER.
• Cobalt modification optimizes the electronic structure of NiFe LDHs, facilitating OER.
• Co-modified NiFe LDHs represent advanced electrocatalysts for efficient oxygen evolution.