Stabilized Rh0-nanoparticles-Montmorillonite clay composite: Synthesis and catalytic transfer hydrogenation reaction

• Montmorillonite clay is activated with mineral acid to generate nanopores of desired dimension.
• Rh0-nanoparticles are generated into the modified Montmorillonite clay.
• The supported Rh0-nanoparticles are found excellent catalyst in transfer hydrogenation of carbonyl compounds to corresponding alcohols.
• The used catalyst is recyclable for several catalytic runs without significant lost in activity.

Rh0-nanoparticles of around 5 nm size distributed homogeneously into the nanopores of acid activated Montmorillonite clay were generated by incipient wetness impregnation of RhCl3, followed by reduction with ethylene glycol. Acid activation of the Montmorillonite clay was carried out by treating with H2SO4 under controlled condition to increase the surface area by generating nanopores upto about 10 nm sizes, which act as a host and stabilize nanoparticles into the pores. The synthesized Rh0-nanoparticles-clay composites characterized by PXRD, SEM-EDX, HRTEM, XPS and N2-adsorption confirm generation of Rh0-nanoparticle below 5 nm size and fully reduced to metallic state. The supported metal nanoparticles serve as efficient heterogeneous catalyst for reduction of some important aromatic carbonyl compounds leading to corresponding alcohols through transfer hydrogenation up to 100% conversion (GC) and selectivity, where isopropanol was used as both solvent and reductant. The catalyst remained active for several runs without significant loss of its catalytic activities.

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