Acta Montanistica Slovaca (Dec 2004)
Mechanochemical Synthesis of Nanocrystalline CdS in a Laboratory and Industrial Mill
Abstract
Nanocrystalline materials have been of interest of more than 20 years and this interest is still increasing. The preparation and characterization of different chalcogenides have attracted a considerable attention due to their important nonlinear properties, luminiscent properties and other important physical and chemical properties. The main cause is in their unusual properties based on the high concentration of atoms in interfacial structures and the relatively simple ways of their preparation. Nanoparticles of semiconductors have many potential applications in the area of advanced materials. These materials can be synthesized via solid state reactions where the recovery degree can be strongly enhanced by the intervention of mechanical activation. Mechanochemical synthesis belongs among the synthesis route which can effectively control and regulate the course of solid state reactions.This paper describes structural and surface properties of cadmium sulphide nanoparticles synthesized in a planetary mill and in an eccentric vibratory mill. The main aim of this paper was to illustrate the potential of this technique for the large-scale production of CdS nanopowder.CdS nanoparticles were successfully synthesized by the mechanochemical route from the cadmium acetate and natrium sulphide. Structure properties of the as-prepared products were characterized by X-ray powder diffraction. X-ray diffraction patterns reveal the crystalline nature of CdS nanoparticles. Hexagonal ¿-CdS greenockite together with cubic hawleyite À-CdS are present among the products of mechanochemical synthesis. The methods of SEM, particle size analysis and low temperature nitrogen sorption were used to analyze the surface composition. The SEM measurements show the aggregates of small nanocrystals in which particle sizes of 5-9 nm were estimated by ScherrerLs formula.The cadmium sulphide nanoparticles are obtained in the simple step, making the process attractive for industrial applications. Industrial ball mills capable of processing large quantities are readily available, consequently the scaling up of the mechanochemical process is possible. The presented solid-state reaction opens its application also for the engineering area of advanced materials synthesis
