The influence of dopants on the catalytic activity of hematite in the ethylbenzene dehydrogenation

The effect of neodymium, lanthanum, aluminum and zirconium on the textural and catalytic properties of hematite was studied in this work, which aimed to develop catalysts to ethylbenzene dehydrogenation, in the presence of steam, the main commercial route to obtain styrene. Hematite and magnetite were found in fresh and spent catalysts, respectively. All dopants increased the specific surface area of the fresh and spent catalysts and made them more resistant against reduction, but only aluminum avoided sintering during reaction. The dopants increased the catalytic activity per area of hematite, except aluminum which acted only as a textural promoter. The selectivity was decreased due to zirconium and lanthanum while the other dopants did not change this parameter. The neodymium-containing catalyst showed high levels of activity and selectivity and was able to work up to 530 °C, without deactivation, being the most promising with regard to styrene production.

The effect of neodymium, lanthanum, aluminum and zirconium on the textural and catalytic properties of hematite was studied to develop catalysts to ethylbenzene dehydrogenation to produce styrene. The neodymium-containing catalyst showed high activity and selectivity and was able to work up to 530 °C, without deactivation, being the most promising for styrene production. Figure shows activity of the catalysts in ethylbenzene dehydrogenation as a function of time at different temperatures for neodymium-doped iron oxide. () 490 °C; (■) 510 °C; (▴) 530 °C and (●) 550 °C. Figure optionsDownload as PowerPoint slide