Engineering cation vacancies in high-entropy layered double hydroxides for boosting the oxygen evolution reaction

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• High-entropy layered double hydroxides (HE-LDHs) are recognized for their potential as electrocatalysts.
• Existing HE-LDHs often exhibit unsatisfactory catalytic activity and stability for the oxygen evolution reaction (OER).
• The high-entropy and cocktail effects contribute to the promise of HE-LDHs.

Purpose of the Study:

• To design and synthesize novel HE-LDHs with improved electrocatalytic performance for the OER.
• To investigate the role of cation vacancies in enhancing the activity and stability of HE-LDHs.

Main Methods:

• Synthesis of FeCoNiCuZn layered double hydroxides (LDHs) incorporating rich cation vacancies.
• Electrochemical characterization to evaluate OER performance, including overpotentials and stability.
• Density Functional Theory (DFT) calculations to understand the mechanism of activity enhancement.

Main Results:

• The designed FeCoNiCuZn LDHs achieved low overpotentials of 227, 275, and 293 mV at current densities of 10, 100, and 200 mA cm⁻², respectively.
• The electrocatalyst demonstrated excellent stability, with almost no decay observed over 200 hours at 200 mA cm⁻².
• DFT calculations confirmed that cation vacancies optimize the adsorption energy of OER intermediates, boosting intrinsic activity.

Conclusions:

• Introducing cation vacancies into HE-LDHs significantly enhances their electrocatalytic activity and stability for the OER.
• FeCoNiCuZn LDHs with cation vacancies represent a promising class of electrocatalysts for efficient energy conversion.
• The findings provide valuable insights into the rational design of advanced catalysts for the oxygen evolution reaction.