High surface area TiO2–ZrO2 prepared by caustic solution treatment, and its catalytic efficiency in the oxidehydrogenation of para-ethyltoluene by CO2

Abstract

High surface area TiO₂–ZrO₂ (1 : 1) has been synthesized by co-precipitation—digestion method using KOH solution as a hydrolyzing agent as well as a digestion medium. The quenching of the mother liquor solution at elevated temperatures resulted in the amorphization of the TiO₂–ZrO₂ mixed oxide. The highest surface area obtained for TiO₂–ZrO₂ by the co-precipitation–digestion method is 256 m² g⁻¹ calcined at 600 °C with complete amorphous nature and having a particle size of less than 5 nm. Herein, we discuss the concept of amorphization of metal oxides based on the digestion times, supported by the characterization of the catalysts and its application in dehydrogenation of substituted benzene, mainly para-ethyltoluene to para-methylstyrene by CO₂ as soft oxidant which showed high conversion and selectivities of 69% and 96%, respectively.