SYNTHESIS AND CHARACTERIZATION OF COMPOSITES BASED ON HALLOYSITE AND BISMUTH NANOESTRUCTURES

Abstract

In this work, nanocomposites based on halloysite nanotubes have been synthesized and characterized. Halloysite is a phyllosilicate with multilayer nanotubular structure. Halloysite nanotubes are a low-cost alternative with similar morphology over carbon nanotubes. In addition, the tubular structure is combined with differences in reactivity between the external surface and internal surface. The nanocomposites were synthesized by the impregnation of precursors over halloysite nanotube surface, after that nanoparticle growth was done in situ. The characterization of the nanocomposites included several spectroscopic techniques such as electronic absorption spectroscopy (UV-Vis). Also, X-ray diffraction was used for structure characterization. The morphology of the nanocomposites was study with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In addition, energy dispersive spectroscopy (EDS) was used in order to determine composition and identify distribution of elements over halloysite. The results indicated that Bi2S3 nanoparticles (Bi2S3 NPs) were successfully deposited on the surface of halloysite nanotubes (HNTs). Bi2S3 nanoparticles synthesized over halloysite surface have a greater diameter than particles synthesized without HNTs as a support; reduction in the peak wide of diffraction patterns and decrement in the bandgap energy value. The development of these nanocomposites account to maintain nanoparticles dispersed all over halloysite and avoiding particle agglomeration. Lastly, halloysite nanotubes contribute to maintain size control and a narrow size distribution of nanoparticles.