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This work describes photocatalytic application of γ-alumina (γ-Al2O3) surface-anchored palladium and palladium oxide nanoparticles (Pd-γ-Al2O3 and PdO-γ-Al2O3 NPs) synthesized by a novel co-precipitation technique. The palladium(0) NPs (Pd-γ-Al2O3) were formed by calcination of the sample in inert medium, whereas PdO NPs (PdO-γ-Al2O3) were obtained by calcination of the sample in atmospheric oxygen. As-synthesized Pd-γ-Al2O3 and PdO-γ-Al2O3 NPs are characterized by X-ray diffraction, Fourier transform-infrared spectroscopy, field emission scanning electron microscopy and photoluminescence (PL) spectra. The PL spectra of Pd-γ-Al2O3 and PdO-γ-Al2O3 NPs display visible-light emissions from 450 to 500 nm at room temperature. This work aims to study the photocatalytic degradation of organic dye pollutants, including bromocresol green (BCG), bromothymol blue, methylene blue and methyl orange using Pd-γ-Al2O3 and PdO-γ-Al2O3 NPs as potential photocatalysts. Experimental parameters, including the admitting concentration of the organic dye solution, Pd-γ-Al2O3 and PdO-γ-Al2O3 photocatalyst dosage, and pH, were varied to ascertain favorable conditions for photocatalytic degradation. The results indicate that the organic dye BCG is completely (100%) degraded in aqueous solution under ultraviolet light, compared with the other organic dyes. Furthermore, Pd-γ-Al2O3 NPs showed better photocatalytic performance than PdO-γ-Al2O3 NPs. The possible photocatalytic degradation mechanism of the organic dyes by Pd-γ-Al2O3 and PdO-γ-Al2O3 photocatalysts is proposed. The studies reveal that Pd and PdO NPs anchored on the γ-Al2O3 surface are promising and effective catalysts for photocatalytic degradation of organic dyes.

Recently, organic ligands have been shown to play a significant role in optical and electronic properties of CdSe quantum dots and also in solar cell applications. We report organic dithiols as novel capping ligands for CdSe quantum dots (QDs). The organic dithiol compounds were designed in such a way that the two thiol groups of a dithiol (acts as a bidentate ligand) can bond directly to an inorganic CdSe QD surface which passivate effectively to show high optical efficiency by promoting interfacial charge transfer. This work would offer a direct and effective pathway to synthesize CdSe QDs that attaches dithiol ligands with aromatic functionality while maintaining the size and shape control of the CdSe QDs. The structure, crystallinity, and optical properties of the dithiol-capped CdSe QDs were analyzed by XRD, TEM, and photoluminescence. The covalent immobilization of dithiols onto CdSe QDs was confirmed by XPS, FT-IR, TGA, XRD and TEM characterizations. Further, the influence of dithiol-type capping ligands on the optical properties of highly luminescent CdSe QDs was investigated. It has been found that the growth rate and the photoluminescence intensity of CdSe QDs were strongly dependent on the type of dithiol ligands. We also experimentally investigated the use of dithiol-capped CdSe QDs in solar cells. The dithiol shell allows for the electron transport from the surface of the QDs, evidenced by better performance as CdSe QDs sensitized solar cells. The power conversion efficiency (η) of CdSe QDs reached up to 0.65%.

Separation of enantiomers of a chiral compound is one of the most interesting and challenging tasks because of their identical physical and chemical properties. Magnetic materials possessing chiral functionality on their surface can not only exhibit magnetic properties but also recognize chirality. Fe3O4@ZrO2 core–shell nano-materials have not been reported previously for chiral separation of racemates. Zirconia has been shown to be the most stable oxide mechanically, thermally and chemically, and shows better physical and chemical properties among inorganic metal oxides. The present work explores core–shell microspheres consisting of a Fe3O4 magnetic core covered by a zirconia shell (Fe3O4@ZrO2) which are immobilized with cellulose tris(3,5-dimethylphenylcarbamate) to get chiral zirconia magnetic microspheres (CZMMs). As-synthesized CZMMs have been applied for the separation of racemic chiral drugs and the results indicate the CZMMs are potential chiral nanomaterials for enantioseparations. Most importantly the synthesized CZMMs have shown an excellent recyclability and can be used for further chiral separations of different kinds of racemates.