Template-free preparation of hollow Sb2S3 microspheres as supports for Ag nanoparticles and photocatalytic properties of the constructed metal-semiconductor nanostructures

A simple and convenient Ostwald ripening route to the morphology- and phase-controlled preparation of hollow Sb2S3 microspheres is developed. The hollow spheres are clusters of smaller microspheres if orange amorphous Sb2S3 colloid is used as the precursor, whereas, if starting from the yellow precursor, the products are regular hollow spheres. By selecting appropriate experimental conditions for ripening, the phase of the hollow Sb2S3 microspheres can be controlled. Amorphous and orthorhombic hollow spheres are prepared by ripening the colloidal precursors at ambient temperature and in an autoclave, respectively. The closed shell of hollow Sb2S3 spheres can be easily eroded by hydrochloric acid to form an open structure. By the in situ reduction of adsorbed Ag+ on the surface and interior of the hollow spheres, Ag nanoparticles are introduced into them, to form functional metal-semiconductor composites, the weight content of which is controlled by regulating the concentration of the Ag+ source and the adsorption time. The composite structures composed of Ag nanoparticles and hollow Sb2S3 spheres exhibit a remarkably enhanced absorption covering the UV and visible regions of the electromagnetic spectrum. A study of the photocatalytic properties of the composite structures demonstrates that exposure to both UV and visible light enables them to induce the rapid decomposition of 2-chlorophenol. The degradation rate increases with a larger weight content of Ag in the composite structure.