The microstructural refinement and performance improvement of a nanoporous Ag/CeO₂catalyst for NaBH₄oxidation

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Nanoporous materials offer high surface areas for catalytic applications.
• Developing efficient catalysts for sodium borohydride oxidation is crucial for fuel cell technology.

Purpose of the Study:

• To investigate the effect of copper (Cu) and cerium (Ce) on the microstructure and catalytic activity of nanoporous silver (Ag) and Ag/CeO2 composite catalysts.
• To optimize the composition of Al-Ag precursor alloys for enhanced catalyst performance.

Main Methods:

• Melt-spinning of Al-Ag precursor alloys with varying Cu and Ce content.
• Dealloying, calcination, and corrosion processes to form nanoporous structures.
• Electrochemical measurements to evaluate catalytic properties for NaBH4 oxidation.

Main Results:

• Al84Ag8Cu8 alloy yielded the finest nanoporous Ag microstructure.
• Addition of Ce to Al84Ag8Cu8 resulted in Ag/CeO2 composites with CeO2 nanorods.
• The Al84Ag8Cu8Ce0.5 precursor produced the best-performing nanoporous Ag/CeO2 catalyst, showing a 2.5-fold increase in current density compared to Al84Ag8Cu8.
• Cu addition improved catalytic properties, while Ce further enhanced them, attributed to refined microstructures and strong Ag-CeO2 interactions.

Conclusions:

• Cu and Ce significantly refine the microstructure of nanoporous Ag and Ag/CeO2 catalysts.
• The optimized nanoporous Ag/CeO2 catalyst exhibits superior catalytic activity for NaBH4 oxidation.
• Refined microstructures, core-shell Ag-Cu phases, and Ag-CeO2 interfaces are key to enhanced catalytic performance.