Green Synthesis of Silver Nanoparticles Using Penicillium Species: pH-Dependent Formation and Catalytic Performance

Abstract

Background: The utilization of Penicillium species for the environmentally friendly synthesis of silver nanoparticles has demonstrated effectiveness, as supported by experimental evidence. This method offers a sustainable alternative for nanoparticle production.

Purpose: The goal of this study was to look into the influence of pH on the optical characteristics, structural attributes, and catalytic performance of silver nanoparticles synthesized using Penicillium species. Understanding the pH dependency provides insights into controlling and optimizing nanoparticle properties.

Research Methodology: Silver nanoparticle synthesis was confirmed through visual inspection and UV-visible spectroscopy, displaying an absorption band for surface plasmon resonance between 408 and 415 nm. Fourier-transform infrared spectroscopy identified biomolecules responsible for nanoparticle stabilization and reduction. X-ray diffraction analysis confirmed the tiny-particles' cubic crystalline structure. The size distribution and shape of the nanoparticles were clarified by transmission and scanning electron microscopy. Photoluminescence spectroscopy examined luminescence properties, while catalytic activity was assessed through methylene blue reduction.

Findings: Higher pH values led to a blue shift and surface plasmon resonance curve that is sharper, influencing the intensity and location of the absorption peak. The nanoparticles exhibited a cubic crystalline structure with a crystallite size of approximately 16.69 nm. They appeared spherical, uniformly distributed, and ranged from 9 to 19 nm in size. Luminescence characteristics were observed, with emission peaks at 530 nm upon excitation at 400 nm. The nanoparticles demonstrated efficient catalytic activity, evidenced by rapid methylene blue reduction when sodium borohydride is present.