Nanopartículas coloidais de ouro e prata e sua funcionalização com dibutil-dicalcogenetos

Abstract

Hybrid materials present interesting combination of the physical and chemical properties of organic and inorganic compounds in a single material that is widely employed in distinct technological applications. In the present work, silver and gold colloids were prepared by means of the Turkevich Method, and hybrid materials were obtained through the surface functionalization of gold nanoparticles with organochalcogen organic molecules (S, Se and Te). The as obtained nanoparticles were characterized by X-ray diffraction, ultravioletvisible absorption spectroscopy and scanning and transmission electron microcopies, while nanoparticles functionalization was observed by means of Xray photoelectron spectroscopy (XPS). During the synthesis, it was verified the influence of pH, temperature, reaction time and ammonium concentration, and results indicated that the reducing species concentration in solution is determined by the pH, influencing in the saturation, nucleation and particles growth process. After the nucleation stage, it was noted that the addtion of ammonium can stabilize the silver colloids, resulting in average particle sizes from 1.6 to 2.2 nm with narrow size distributuin. The XPS analyses revealed that the dibutil-diselenol molecules were more stable in the oxidation processes than of dibutil-ditiol and dibutil-ditellurol, presenting oxidized molecules of 6%, 34% and 92%, respectively.