Gold Nano-Particles Modified Ito Electrode By Electrochemistry And Photoelectrocatalysis To Formaldehyde

The chemically modified electrodes have been a hot topic since they were developed in the middle of1970’s. When some mediators were modified on the electrode, it could be used to facilitate the electron transfer and catalyze the electrochemical reaction. It has been widely applied in many areas such as life science, environmental science, analytical science and material science, etc. Small size of nano-materials produced many specific optical and electricl phenomena. On the other hand, gold nano-particles (AuNPs) have been widespread concerned in recent years because of its excellent biological compatible and superior catalytic performance.In this paper, an effective approach to deposit AuNPs directly on indium tin oxide (ITO) surface through electrochemical method is reported. Gold nano-particles modified ITO electrode was obtained as following processes:A novel AuNPs modified ITO electrode was prepared with the seed mediated growth method. Firstly a seeded AuNPs was modified on the ITO surface, then HAuCl4were reduced directly on Au nano-seeds modified ITO surface using constant potential electrolysis. The prepared electrode was characterized by UV-VIS, AFM, SEM and electrochemical motheds. The experimental results showed that AuNPs were successfully deposited and flower-like structures were obtained on modified ITO films. The diameter of these flower-like structures was in the range of80～120nm, good dispersibility. The electrode had good stability and repeatability.The electrocatalytic and photoelectrocatalytic behavior of formaldehyde on the AuNPs modified ITO electrodes with the seed mediated growth method was investigated by cyclic voltammetry (CV).The experimental results demonstrated that the AuNPs modified ITO electrodes with the seed mediated growth method had a better catalytic effect on the electrochemical oxidation and photoelectrochemical oxidation of formaldehyde than common AuNPs modified ITO electrodes. Good synergistic effect was observed when the electrocatalysis and the photocatalysis were combined, especially the current signal intensity of photoelectrocatalytic oxidation of formaldehyde was bigger than electrocatalysis alone. The photoelectrochemical determination of formaldehyde was performed in0.1M NaOH solution. In the range of10mg/L to100mg/L, the peak current was linearly proportional to the concentration of formaldehyde. The detection limit was estimated to be0.29mg/L...