Silver nanoparticle-decorated NiFe₂O₄/CuWO₄ heterostructure electrocatalyst for oxygen evolution reactions

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Developing efficient electrocatalysts is crucial for energy conversion technologies.
• Nickel-iron oxides and copper tungstates are promising materials for oxygen evolution reaction (OER).
• Silver nanoparticles can enhance catalytic activity through synergistic effects.

Purpose of the Study:

• To synthesize and characterize Ag nanoparticles decorated NiFe2O4/CuWO4 heterostructures.
• To investigate the effect of varying Ag loading on the electrochemical OER performance.
• To understand the structure-activity relationship for optimized OER catalysis.

Main Methods:

• Step-wise precipitation method for synthesizing Ag-loaded NiFe2O4/CuWO4 heterostructures.
• Electrochemical characterization using linear sweep voltammetry (LSV) in 1 M KOH.
• Analysis of overpotential, Tafel slope, and onset potential for OER performance evaluation.
• Long-term stability testing over 24 hours.

Main Results:

• The heterostructure with 5 wt% Ag loading exhibited optimal OER performance.
• Achieved a low overpotential of 1.60 V vs. RHE at 10 mA cm-2 with a Tafel slope of 44.5 mV dec-1.
• Demonstrated excellent stability over 24 hours with minimal overpotential increase.
• Enhanced performance attributed to synergistic effects, diverse oxygen-vacant sites, and improved charge transfer kinetics.

Conclusions:

• Optimized Ag loading on NiFe2O4/CuWO4 heterostructures significantly enhances OER activity and stability.
• The developed composite presents a promising strategy for cost-effective, next-generation electrocatalysts.
• Engineering microstructure and optimizing noble metal loading are key for advanced energy applications.