High entropy rare-earth Prussian blue analogues for boosting oxygen evolution catalysis

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing efficient catalysts for the oxygen evolution reaction (OER) in alkaline media is critical for energy applications.
• Metal-organic frameworks (MOFs) offer tunable structures for catalytic applications.
• High-entropy materials show promise in enhancing catalytic performance through synergistic effects.

Purpose of the Study:

• To introduce high-entropy technology into metal-organic frameworks for improved OER performance.
• To synthesize and characterize novel high-entropy porous coordination polymers (PBAs).
• To evaluate the electrocatalytic activity and stability of the developed catalyst in alkaline environments.

Main Methods:

• A facile, one-step room-temperature co-precipitation method was employed for catalyst synthesis.
• X-ray photoelectron spectroscopy (XPS) and elemental mapping were used for material characterization.
• Electrocatalytic performance was assessed through cyclic voltammetry and chronoamperometry in alkaline solutions.

Main Results:

• The synthesized high-entropy PBA, NiFeLaMoCo-PBA, exhibited a cubic-like crystal structure.
• NiFeLaMoCo-PBA demonstrated excellent OER activity with an overpotential of 244 mV at 10 mA cm⁻² and a Tafel slope of 32 mV dec⁻¹.
• The catalyst maintained stability for 48 hours at a current density of 50 mA cm⁻² in 1 M KOH.

Conclusions:

• The strategic incorporation of multiple metal elements (Fe, La, Mo) into the high-entropy PBA architecture significantly enhances OER activity and stability.
• Multimetallic synergistic effects and optimized electronic structures contribute to the improved catalytic performance.
• NiFeLaMoCo-PBA presents a promising, cost-effective electrocatalyst for efficient OER in alkaline media.