Catalytic Reduction of 4-Nitrophenol Using Silver Nanoparticles with Adjustable Activity

Area of Science:

• Materials Science
• Nanotechnology
• Catalysis

Background:

• Silver nanoparticles (AgNPs) are widely used in catalysis and biomedical applications.
• Developing stable, well-characterized AgNPs is crucial for reliable comparative studies.
• The polyol process is a common method for synthesizing metal nanoparticles.

Purpose of the Study:

• To synthesize and characterize ultrasmall core-shell silver nanoparticles for use as reference materials.
• To investigate the catalytic activity of these AgNPs with different surface stabilizers.
• To demonstrate the potential for surface functionalization with biomolecules.

Main Methods:

• Upscaled modification of the polyol process for nanoparticle synthesis.
• Small-angle X-ray scattering (SAXS) for core size analysis.
• Dynamic light scattering (DLS) for hydrodynamic size and PDI determination.
• Surface functionalization by exchanging poly(acrylic acid) (PAA) with biomolecules like glutathione (GSH) and bovine serum albumin (BSA).
• Catalytic evaluation of the reduction of 4-nitrophenol to 4-aminophenol.

Main Results:

• Successfully synthesized ultrasmall core-shell AgNPs with a mean silver core radius of 3.0 nm and a shell thickness of 7.0 nm.
• Achieved excellent colloidal stability (>6 months) with PAA coating.
• Demonstrated high catalytic activity (436 ± 24 L g(-1) s(-1)) with PAA stabilization, the highest reported for AgNPs.
• Showed significant reduction in catalytic activity upon surface modification with GSH (77.6 ± 0.9 L g(-1) s(-1)) and BSA (3.47 ± 0.50 L g(-1) s(-1)).

Conclusions:

• The developed ultrasmall core-shell AgNPs serve as effective reference materials.
• Surface modification significantly impacts the catalytic activity of AgNPs.
• PAA-stabilized AgNPs exhibit superior catalytic performance for 4-nitrophenol reduction.