Flower-like Al2O3-supported iron oxides as an efficient catalyst for oxidative dehydrogenation of ethlybenzene with CO2.

An Al 2 O 3 support with flower-like morphology was used as the support of iron oxide catalyst for oxidative dehydrogenation of ethylbenzene with CO 2 . A commercial Al 2 O 3 was also used for comparison. These catalyst materials were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), N 2 physisorption, H 2 temperature programmed reduction (H 2 -TPR), cyclic voltammetry (CV), electron paramagnetic resonance (EPR), X-ray photoelectron spectroscopy (XPS) and CO 2 temperature programmed desorption (CO 2 -TPD) techniques. It was found that the concentration of O 2− anions on the flower-like Al 2 O 3 surface was significantly higher than that on the commercial Al 2 O 3 surface, leading to large amounts of highly dispersed Fe x O y clusters on flower-like Al 2 O 3 in contrast with large Fe 2 O 3 particles mainly present on commercial Al 2 O 3 . A possible formation mechanism of the small Fe x O y clusters was proposed. The catalytic results indicated that the highly dispersed Fe x O y clusters possessed an excellent catalytic activity, since the ethylbenzene conversion over Fe 2 O 3 /flower-like Al 2 O 3 was 1.6 times higher than that over Fe 2 O 3 /commercial Al 2 O 3 . This work provides a new route for designing supported iron catalysts that are widely used, and flower-like Al 2 O 3 is expected to be a promising catalyst support for oxidative dehydrogenation of ethylbenzene with CO 2 . [ABSTRACT FROM AUTHOR]