Preparation Of The â…¡-â…¥ Metallic Sulfide Nanoparticles By Electrochemical Method And Their Properties

TheⅡ-Ⅵmetallic sulfide(CdS,ZnS) nanoparticle is one kind of an important semiconductor material with some particular photoelectrical properties. It is of great importance for photoelectrochemical biosensors, luminescent probes, photoelectrocatalysis, solar cells and other opo-electronic products. Recently, with the development of nanotechnology, the significant status of CdS and ZnS Quantum Dots has drawn much attention and a great number of synthetic methods have been developed. The diameter, density, uniformity, structure and other properties of particles depend on the preparing conditons and methods.In this paper, we firstly explored a convenient route to prepare cadmium sulfide (CdS) nanoparticle. CdS nanoparticle was directly deposited on the ITO surface by cyclic voltammetry (CV) using CdCl2 and Na2S2O3 as electrolyte. We studied several factors, including the potential range, the concentration of electrolyte and the sweep segment of CV,that influence the diameter, density, uniformity and structure of the nanoparticles. The prepared CdS nanoparticle was characterized by scanning electron microscope (SEM), UV-Vis spectroscopy and X-ray diffraction (XRD). When the CdS nanoparticle was electrodeposited from 0.1M CdCl2 and 0.02M Na2S2O3 mixed electrolyte in the range of -0.2V to -0.8V for 40 segment at 50℃, the average diameter of CdS nanoparticles are about 60 nm with uniformity and dispersibility.Secondly, Zinc sulfide (ZnS) nanoparticle was prepared using ZnCl2 and Na2S2O3 as electrolyte according to the preparation method of CdS. At the same time, the core-shell and alloy nano-modified electrodes of CdS and ZnS were also fabricated. Afterwards, these QDs modified electrodes were used to study the photoelectrocatalytic reaction to methyl orange (MeO) which is a typical organic pollutant. The results indicate that ITO/CdS, ITO/ZnS electrode, their core-shell and alloy nano-modified electrode all have a photoelectrocatalytic effect on MeO more or less. The current of CV and I-T both increased significantly after illuminating. And the ITO/CdS electrode has the highest current both before and after illuminating. The I-T current of ITO/ZnS modified electrode increased about 89% when light was on, which is the highest among those electrodes. It reveals that the ITO/ZnS modified electrode has the most apparent photoelectrocatalytic effect on MeO.Finally, the glucose oxidase (GOD) was immobilized on the ITO/ZnS nano-modified electrode using sol-gol method. The direct electron transfer between GOD and electrode was realized. Besides, we studied the CV effect of different enzyme electrodes. The result revealed that the ITO/ZnS/SG-GOD electrode has the most significant CV effect among these electrodes. ITO/ZnS/SG-GOD electrode appears a pair of an evident oxidation-reduction peak at -0.429V and -0.398V. The difference between the cathodic and anodic peak potentials is 31mV and the Eo is -0.414V. The electrochemical behaviors of the ITO/ZnS/SG-GOD electrode were studied under the optimized condition and the ks was evaluated to be 5.73s-1.