Molecular insights on benzoic acid, 3-hydrazino-4-methyl-, ethyl ester-modified gold nanoparticles for improved SERS sensing and photocatalytic degradation of dye contaminants

This study reports the biosynthesis of gold nanoparticles (AuNPs) for the dual purposes of sensing and degrading organic dye pollutants in textile wastewater. Fruit extracts of Averrhoa carambola (AC) and Morus alba (MA) were used as reducing and stabilizing agents in the biosynthesis of AuNPs. Spherical MA-AuNPs and AC-AuNPs measured 16 nm and 21 nm, respectively, with characteristic surface plasmon resonance peaks at 541 nm and 543 nm. FTIR and Raman spectroscopy revealed functional group modifications involved in bioreduction. Density Functional Theory (DFT) calculations were employed to investigate the molecular interaction between benzoic acid-3-hydrazino-4-methyl-ethyl ester (C₁₀H₁₄N₂O₂) and Au₂ clusters, elucidating the enhanced inhibitory action attributed to AC- and MA-extracts, as confirmed by GC–MS analysis. The C₁₀H₁₄N₂O₂-functionalized AuNPs'performance as a Surface-Enhanced Raman Scattering (SERS) sensor and photocatalytic substrate was investigated using commercial dyes (CR, MB, Rh B, and CV) in wastewater.