Facile synthesis of heterogeneous recyclable Pd/CeO2/TiO2 nanostructured catalyst for the one pot hydroxylation of benzene to phenol

Abstract

In this work we adopted, a facile method to synthesis Pd/CeO2/TiO2 nanocomposite in large scale and evaluated its catalytic property towards the benzene hydroxylation into phenol. The as-synthesized Pd/CeO2/TiO2 composite was vigilantly investigated using XRD, SEM, TEM, elemental mapping, XPS, TGA and BET studies. The uniformly dispersed Pd/CeO2/TiO2 with size 5–20 nm shows the high benzene conversion of 73% with 95% selectivity of phenol at 80 °C. The influence of various reaction conditions such as role of solvents, temperature, benzene to peroxide molar ratio, reaction time, etc were specifically investigated. The catalyst also showed pronounced photocatalytic activity for hydroxylation of benzene under the visible light conditions. The heterogeneity of the catalyst was additionally confirmed by Sheldon’s hot filtration test where no leaching up to 5 cycle, confirming the heterogeneity of the catalyst.