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We report the synthesis of peroxo titanium carbonate complex solution as a novel water-soluble precursor for the direct synthesis of layered protonated titanate at room temperature. The synthesized titanates showed excellent removal capacity for Pb(2+) and methylene blue. Based on experimental observations, a probable mechanism for the formation of protonated layered dititanate sheets is also discussed.

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CeO2 as one of the most promising oxidation catalysts has attracted much attention because of its superior performance. The extent of oxidation properties is controlled by the ratio of Ce3+/Ce4+, particle size, and surface area. Here, a facile low-temperature aqueous solution-based chemical route for the synthesis of CeO2 and samarium-doped CeO2 (Sm−CeO2) nanoparticle aggregates, with high content of Ce3+ and surface area, using aqueous solution of ammonium carbonate complex of cerium is presented. The morphologies and structures of the prepared CeO2 nanoparticle were characterized by X-ray diffraction (XRD), thermal analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and hydrogen-temperature programmed desorption. The synthesized CeO2 and Sm−CeO2 nanoparticle aggregate showed significantly improved catalytic activity toward allylic oxidation to corresponding en-ones compared to bulk CeO2. The present method provides a new and facile strategy toward the synthesis of CeO2 and Sm−CeO2 nanoparticle aggregates with extensive applications.

Design of hierarchical nanostructures towards a specific morphology is an important research area due to their shape dependent properties. Here, 3D hierarchically assembled lotus shaped porous MnO 2 is synthesized using a simple aqueous solution based chelating agent (citric acid) mediated growth of MnCO 3 followed by calcination at 350 C. MnCO 3 in other shapes, such as rods, spheres and nanoaggregates, is also synthesized just by varying the chelating agents. It is observed that the geometry and strength of the chelating ligands has a crucial role in the controlled shape selective synthesis and based on this a probable chelating agent driven formation mechanism is discussed. The synthesized porous MnO 2 shapes exhibit excellent shape dependent catalytic oxidation of a-pinene to verbenone using molecular oxygen as the oxidant. The lotus shaped porous MnO 2 shows superior activity, with 94% conversion of a-pinene and 87% selectivity of verbenone, to that of other MnO 2 shapes. The activity is reasonably high compared to heterogeneous as well as homogeneous catalysts reported in the literature and bulk MnO 2 with respect to both their conversion and selectivity. The synthesized lotus shaped MnO 2 also showed good catalytic activity towards oxidation of allylic compounds to corresponding ene-ones using molecular oxygen as oxidant and is reusable.

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We present a new strategy for the fabrication of magneto-fluorescent nanoparticles designed for bimodal imaging. These hybrid nanostructures comprise an optically active semiconductor nanoparticle quantum dot core with tunable fluorescence, encapsulated within a hollow paramagnetic iron oxide shell that serves as an MRI contrast agent. The yolk–shell morphology enables incorporation of the semiconductor and magnetic domains into a single structure, while avoiding direct contact between them, which typically results in quenching of the desired optical fluorescence. We successfully demonstrate utilization of the ultrasmall (15 nm hydrodynamic size) magneto-fluorescent CdSe@CdS@Hollow-Fe2O3 nanoparticles for multimodal imaging of cells at the intracellular level.