Electrophoresis deposition of Au nanoparticles on FTO electrode for As(III) detection

Abstract

Gold nanoparticles (AuNPs) were synthesized via redox reaction, using EDTA as a protecting and reducing agent, with HAuCl₄, as precursor and seed solution. The appropriate reaction condition was found out, with the ratio of EDTA:HAuCl₄ 10:1, 40 µL of seed solution and stirring time of 5 minutes. The UV-Vis spectroscopy observed that the appearance of two absorption peaks were at 574 and 755.5 nm with the average size of AuNPs was 64.5 nm, the zeta potential was positive. The synthesized AuNPs were deposited on FTO electrode by electrophoresis deposition. The results of solid UV-Vis and SEM images showed that the spherical AuNPs ranging from 40 to 60 nm were deposited onto FTO to fabricate the AuNPs/FTO electrodes. The electrochemical activity of AuNPS/FTO were investigated based on the redox reaction of hydroquinone; the CV results showed the electrode with applied potential at 20 V for 60 minutes has the superior performance. The analysis of As(III) were conducted by AS-SWV technique. The results showed that AuNPs/FTO electrode enable to detect As(III) at the concentrations higher than 5 ppb that is suitable for the WHO standard of domestic water.