Green synthesis, characterisation of Au and Ag nanoparticles by various bioextracts and their usability at graphite electrode modification

In this study, the biosynthesis of Au and Ag nanoparticles (AuNp and AgNp) with a green chemistry approach was performed by using bioextracts of various fruits and vegetables (Lycopersicon esculentum (LE), Cucumis sativus (CS), Malus domestica (MD), Cucurbita pepo (CP), Apiumgraveolens var. rapaceum (AVR), Prunus cerasifera (PC), Oleraceae var. botrytis (OVB)). In the determination of optimum experimental conditions, the parameters such as the type and concentration of bioextract, concentration of metal ion solutions, the ratio of metal ion solution to bioextract, pH, reaction time and temperature were found to be significant. The characterisation of AuNp and AgNp synthesized by providing the most appropriate experimental conditions was performed by UV-Vis., SEM, EDX, XPS and FTIR techniques. The characterisation study showed that, AuNp and AgNp were successfully synthesized and detailed information was obtained about their stabilities, sizes, homogeneities etc. In the final step, the usability of the green synthesized nanoparticles in the modification of pencil graphite electrodes (PGE) was investigated. Electrochemical characterisation of AuNp/GE and AgNp/GE electrodes was performed using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. The obtained results and calculated electrochemical parameters showed that these modified electrodes have better conductivity, electron transfer rate and electrocatalytic activity.