Eco-friendly synthesis of carob- and ginger-modified gold nanoparticles for enhanced catalytic applications

This study aimed to investigate the catalytic performance of gold nanoparticles (AuNPs) obtained by using ginger and carob antioxidant plants as reducing and stabilizing agents. In the first stage of the study, AuNPs were successfully produced using these herbal extracts via a green synthesis method, without the need for toxic chemicals, in a sustainable, economical, rapid, energy-efficient, and easy way. In the second stage, the structural analysis and catalytic applications of the obtained AuNPs were investigated. Advanced techniques such as Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), UV-Vis spectroscopy, and energy dispersive X-ray spectroscopy (EDX) were used to elucidate the morphological, optical, and structural properties of AuNPs in detail. In UV-Vis analyses, the observation of characteristic surface plasmon resonance (SPR) peaks in the range of 532-540 nm confirmed that AuNPs were successfully synthesized. In the catalytic application dimension of the study, the efficiency of the obtained AuNPs in the degradation of common industrial dyes such as rhodamine B, methyl orange, and methylene blue with NaBH₄ reduction was investigated. The nanoparticles exhibited high catalytic performance in the reduction of the dyes in question, and the reaction processes were completed in a short time (approximately 8-12 min). The kinetics of these reduction reactions were evaluated within the framework of the Michaelis-Menten kinetic model; important parameters such as reaction rate constants (k) and half-life (t_1/2) were calculated. The calculated values of K_M = 3.45 mg L^-1 and <i>v</i> _max = 0.78 mg L^-1 min^-1 for Gng-AuNPs reveal that this catalyst exhibits higher affinity for dyes and operates more efficiently at lower concentrations. The findings obtained reveal that AuNPs synthesized using plant antioxidants not only offer an environmentally compatible production process, but also, due to their high catalytic efficiency, provide a potential alternative for the removal of environmental pollutants. In this respect, these nanoparticles offer innovative and applicable solutions in the field of sustainable chemistry and environmental technologies.