Sonochemical-assisted synthesis of highly stable gold nanoparticles catalyst for decoloration of methylene blue dye

Abstract

Gold nanoparticles (AuNPs) can be easily synthesised using several methods for various applications in the industrial and medical sectors. However, their performance as a catalyst has not yet to be appropriately studied and optimised due to large size distribution and high agglomeration property. In this work, AuNP were synthesized by a sonochemical method using sodium citrate as a reducing agent and capping material. A Vibra-Cell ultrasonic solid horn with a half-inch tip size, frequency of 20 kHz and different ultrasound output powers (12, 20 and 36 W) was used in the synthesis. The as-synthesized AuNPs exhibited a spherical morphology with smooth geometry, excellent stability and high monodispersity after 10 min of sonication. AuNPs sizes decreased with increased sonication output power, which implies that the particle size, surface plasmon resonance, stability and monodispersity of the AuNPs depended on ultrasound output power and reaction time. Overall, this study showed that the sonochemical synthesis of AuNPs was an easy and controllable approach and can be potentially applied to fabricate other nanosized particles. AuNP's catalytic efficiency for the degradation of methylene blue has a fast decoloration rate of about 10 min.