Effect of TiO2 on the structure and catalytic behavior of iron–potassium oxide catalyst for dehydrogenation of ethylbenzene to styrene

The effect of TiO2 addition on the structure and catalytic behavior of iron–potassium catalyst for ethylbenzene dehydrogenation to styrene was investigated. The catalysts were characterized by X-ray diffraction (XRD), temperature-programmed reduction technique (TPR), X-ray photoelectron spectra (XPS) and Mössbauer spectroscopy. XRD and Mössbauer results showed that the addition of TiO2 increased the number of active phase KFeO2 of catalyst and improved the dispersion of CeO2 promoter, whereas excessive addition inhibited the formation of K2Fe22O34, the precursor of active phase KFeO2. TPR and XPS results indicated that appropriate addition of TiO2 decreased the reduction temperature of catalyst and deactivation of catalyst was correlated with the ration between Fe3+ and Fe2+. Activity test showed that Ti promoter increased the initial activity of catalyst. An appropriate amount of Ti would increase the catalyst activity, whereas the excessive addition of Ti deteriorated the catalyst stability.