Microplasma-assisted green synthesis of glucose-stabilized silver nanoparticles: a dual-functional platform for SERS detection and synergistic reduction of binary dyes

Abstract

A rapid and environmentally sustainable approach for synthesizing glucose-stabilized silver nanoparticles (G-AgNPs) was developed using an atmospheric-pressure microplasma process that completely eliminates the need for conventional chemical reductants and surfactants. The synergistic interaction between plasma-generated reactive species and glucose molecules enabled the one-step formation of uniformly dispersed AgNPs exhibiting dual morphologies—spherical (∼8 nm) and hexagonal (∼16 nm)—with distinct localized surface plasmon resonances (LSPR) centered at ∼403 nm. These nanostructures produced abundant electromagnetic “hot spots,” functioning as highly sensitive and reproducible SERS substrates capable of detecting Rhodamine 6G at concentrations as low as 10⁻⁹ M (enhancement factor = 8.31 × 10⁷, RSD = 4.85%, n = 9). Simultaneously, the G-AgNPs demonstrated excellent catalytic activity toward the NaBH₄-assisted reduction of methylene blue (MB) and rhodamine B (RhB), following pseudo-first-order kinetics with rate constants of k_MB = 0.111 min⁻¹ and k_RhB = 0.071 min⁻¹ for single-dye systems, and k_MB = 0.085 min⁻¹ and k_RhB = 0.068 min⁻¹ for the binary mixture (R² ≥ 0.97). The enhanced redox performance is consistent with a Langmuir–Hinshelwood-type surface-mediated mechanism, in which the glucose shell promotes electrostatic adsorption, mediates interfacial electron transfer, and enhances the colloidal stability of the AgNPs. By coupling plasmonic amplification with efficient catalytic reduction, the proposed microplasma-glucose strategy introduces a novel dual-functional nanoplatform for trace-level molecular detection and sustainable pollutant remediation.