Billakanti Srinivas

The focus of the work is the synthesis of SnS₂ nanomaterials with (peg-SnS₂NF) and without (sf-SnS₂NR) the involvement of the organic template and the comparative study of their catalytic activities. The synthesis of these materials was achieved in a single-step procedure aided by hexamethyldisilazane (HMDS). These nanoparticles were subjected to X-ray diffraction, transmission electron microscopy, scanning electron microscopy, Raman spectroscopy, and UV–vis spectroscopy analyses to investigate their structural, topographical, surface, and optical properties. The present work suggests that the surfactant-free SnS₂ nanoring (sf-SnS₂NR) catalyst has lower surface area compared to the poly(ethylene glycol)-stabilized SnS₂ nanoflower (peg-SnS₂NF) catalyst but shows high activity under visible light for the photoreduction of Cr(VI) and the photocatalytic degradation of organic dyes. The work exposed the importance of the clean surfaces on the catalyst and is expected to have a high impact on the photocatalytic activity of the SnS₂ nanomaterial. The study also endorses the utility of the HMDS-assisted synthetic method for the production of multifunctional semiconductor tin disulfide nanomaterials with multiple potential applications.

The synthesis of surface‐clean nanoparticles of Ni ₃ S ₄ , which is a rare phase of nickel sulphides, is described. Nanoparticles were synthesized in a single step via hexamethyldisilazane (HMDS) –assisted method using NiCl ₂ and thiourea as starting materials. This synthetic method yielded phase pure, spherical Ni ₃ S ₄ nanoparticles of mean size 17 ± 4 nm having clean surfaces. The nanoparticles were characterized thoroughly by data obtained from Powder X‐ray diffraction (PXRD), Fourier‐transform infrared spectra (FT‐IR), Energy dispersive X‐ray analysis (EDAX) and Transmission electron microscopy (TEM) analyses. Since newly produced Ni ₃ S ₄ nanoparticles in our reaction had exposed surfaces, the catalytic behaviour of these particles was assessed by using it as a catalyst in the reduction reaction of aromatic nitro groups. We have demonstrated Ni ₃ S ₄ nanoparticle as a versatile catalyst for the nitro hydrogenation of both activated and deactivated nitrobenzenes using hydrazine as a hydrogen source to yield corresponding amines in high yield (∼90 %). The heterogeneous catalyst, Ni ₃ S ₄ nanoparticles was recycled more than ten times without any change in its activity. We have ascribed the enhanced catalytic activity of these Ni ₃ S ₄ nanoparticles to their clean surfaces without any surfactant molecules around them.