Mesoporous KIT-6 supported Cr and Co-based catalysts for microwave-assisted non-oxidative ethane dehydrogenation

Abstract

In the present study, mono and bi-metallic catalysts containing Cr and Co were prepared by impregnating the hydrothermally prepared mesoporous KIT-6 support with 5–10 wt% total metal content. The well-ordered three-dimensional mesoporous structure of the KIT-6 support was confirmed by small angle X-ray diffraction (XRD) patterns. N2 adsorption-desorption analysis results showed that the mesoporous structure of KIT-6 was preserved after metal loading. Structural bonds of KIT-6 support and prepared catalysts were determined by Fourier-transform infrared (FT-IR) spectroscopy. The pyridine adsorbed diffuse reflectance FT-IR (DRIFT) spectroscopy results revealed the presence of Lewis acid sites on the surface of the catalysts. Activity experiments were carried out in a microwave-heated continuous-flow fixed bed reactor system at temperature range of 350–650 °C and feed ratios of Ethane/Argon: 1/2, 1/1, 2/1 with a gas hourly space velocity (GHSV) of 18,000 ml/h.gcat. The 5Cr@KIT-6 catalyst exhibited high ethane conversion (63.5%) while the highest ethylene/hydrogen ratio (0.98) was obtained with the 2.5Cr2.5Co@KIT-6 catalyst at 450 °C. It was concluded that high temperatures (above 450 °C) facilitate the formation of side reactions and the production of aromatic compounds. The high catalytic activities of mesoporous catalysts were thought to be due to hot spots in the microwave reactor system.

Excess-Methane CO2 Reforming over Reduced KIT-6-Ni-Y Mesoporous Silicas Monitored by In Situ XAS–XRD

“…After modification with Ni, the height of the hysteresis loop decreased compared to KIT-6, whereas the width of the hysteresis loops remarkably increased after yttrium addition. The former can be linked with a decrease in pore volume, whereas the expansion of the hysteresis can be due to the change in the structure of pores caused by metal loading . The detailed textural parameters are given in Table .…”

“…The former can be linked with a decrease in pore volume, whereas the expansion of the hysteresis can be due to the change in the structure of pores caused by metal loading. 25 The detailed textural parameters are given in Table 1 . The bare KIT-6 support exhibited a relatively large specific surface area of 733 m 2 /g, as well as a high pore volume of 0.88 cm 3 /g.…”