Hybrid ceria and chitosan supported nickel nanoparticles: A recyclable nanocatalytic system in the reduction of nitroarenes and the synthesis of benzopyran derivatives in green solvent

Mesoporous, highly temperature resistant, magnetically separable, bimetallic, and organic-based photoluminescent nanocatalyst has been prepared. Chitosan can act efficiently as a support material for preparing nanocatalysts. Hybrid ceria, that is, iron-doped-cerium oxide (Fe@CeO2), was prepared via coprecipitation method. Chitosan-iron-doped-ceria nanocomposite was prepared and kept in a solution of NiCl2 to adsorb Ni2+ ions, which were then reduced with NaBH4 to accumulate nickel nanoparticles. The characterization of nanocatalyst was performed using different techniques such as X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscope (HR-TEM), energy dispersive X-ray spectra (EDX), Brunauer-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA) analysis. The catalyst was found to have a very small size about 2-3 nm and having a large surface area of about 121 m(2) g(-1), which was stable up to 800 degrees C. It was also found to be photoluminescent. The catalyst thus prepared is useful for the reduction of nitroarenes, which is a toxic compound that is often found as a pollutant in the environment, to anilines, key intermediates for the fine chemical, agrochemical, and pharmaceutical industries. Also, nanocatalyst was used for the synthesis of various substituted tetrahydrobenzo[b]pyrans, which is an essential structural component in various natural products, in good to excellent yields.

Automated summary

A mesoporous, highly temperature resistant, magnetically separable, bimetallic, and organic-based photoluminescent nanocatalyst was prepared using chitosan as a support material. The catalyst exhibited excellent catalytic activity and stability, and was capable of reducing toxic nitroarenes to anilines, which are key intermediates for fine chemical, agrochemical, and pharmaceutical industries. Additionally, the nanocatalyst was effective in synthesizing various substituted tetrahydrobenzo[b]pyrans in good to excellent yields, which are essential structural components in various natural products.