Engineering B-Site Configurational Entropy in Perovskite Oxides for Enhanced Alkaline Oxygen Evolution Reaction

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Lanthanum-based perovskite oxides exhibit sluggish oxygen evolution reaction (OER) kinetics.
• High-entropy composition design can potentially overcome these kinetic limitations.

Purpose of the Study:

• To investigate the effect of B-site configurational entropy on lanthanum-based perovskite oxides for OER.
• To synthesize and characterize low-, medium-, and high-entropy perovskite oxides (HEPOs).

Main Methods:

• Sol-gel combustion synthesis of LaCoO3, La(FeCoNi)O3, and La(MnFeCoNiCu)O3.
• Characterization of morphology, crystal structure, and electronic environment.
• Electrochemical evaluation of OER performance in alkaline media.

Main Results:

• High-entropy design led to reduced particle size, modulated B-site valence states, and enriched oxygen vacancies.
• Synergistic effects among active sites and activated lattice oxygen participation were observed.
• The HEPO demonstrated a low overpotential (303 mV at 10 mA cm⁻²), small Tafel slope (43 mV dec⁻¹), and excellent stability (>100 h).

Conclusions:

• B-site configurational entropy plays a crucial role in enhancing OER activity in perovskite oxides.
• High-entropy design is a promising strategy for developing advanced OER electrocatalysts.
• The study provides insights into structure-property relationships for efficient OER catalysis.