Nanocrystalline Pt-CeO2 as an efficient catalyst for a room temperature selective reduction of nitroarenes

Abstract

We have developed a new synthesis strategy to prepare Pt nanoparticles with size between 2 and 5 nm supported on CeO₂ nanoparticles with size between 30 and 60 nm by the hydrothermal method in the presence of the surfactant cetyltrimethyl ammonium bromide (CTAB) and a polymer (PVP). It was found that the catalyst is highly active for the chemoselective hydrogenation of nitro compounds in aqueous medium in the presence of molecular hydrogen at room temperature (25 °C). The catalyst was characterized by XRD, ICP-AES, XPS, BET-surface area measurements, SEM, TEM and EXAFS. Different reaction parameters like reaction time, catalyst ratio, Pt loading etc. were studied in detail. The investigation revealed that the site of Pt plays a crucial role in the activity by favouring the reduction of nitro-compounds. The catalyst shows >99.9% conversion of nitro-compounds with 99% selectivity of amino compounds. The reusability of the catalyst was tested by conducting the experiment with the same catalyst and it was found that the catalyst does not change its activity and selectivity even after five reuses.