Selective oxidation of styrene over nanostructured cerium–bismuth mixed oxide catalysts

Abstract

In this study, we have prepared CeO₂, Bi₂O₃, and ceria–bismuth mixed oxide (Ce_0.8Bi_0.2O₂, Ce_0.7Bi_0.3O₂, and Ce_0.5Bi_0.5O₂) catalysts using a coprecipitation method. The synthesized catalysts were characterised to understand their structure, morphology, and surface area using a variety of physicochemical characterization techniques namely, XRD, BET surface area analysis, Raman spectroscopy, SEM, TEM, XPS, and H₂-TPR. All catalysts were evaluated for the oxidation of styrene in a round bottomed flask using TBHP as the oxidant. The Bi-doped ceria (Ce_0.7Bi_0.3O₂) catalyst showed higher oxygen vacancies and redox behaviour which is consistent with its superior catalytic activity for styrene oxidation and epoxide product selectivity. Catalytic activity parameters like temperature, reaction time, catalyst amount, substrate/oxidant ratio, and nature of solvent were optimized to obtain better conversion of styrene and selectivity to styrene epoxide.