Oxidative dehydrogenation of ethane with carbon dioxide over Cr2O3/SBA-15 catalysts: the influence of sulfate modification of the support

Abstract

Unmodified and sulfate-modified SBA-15-supported Cr 2 O 3 catalysts were prepared by impregnation method. The physico-chemical properties of the supports and catalysts were determined by nitrogen adsorption/ desorption, powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), laser-Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), UV-Vis diffuse reflectance spectroscopy (UV-DRS), inductively coupled plasma optical emission spectroscopy (ICP-OES), transmission electron microscopy (TEM) and temperature-programmed reduction (TPR) techniques. Oxidative dehydrogenation of ethane to ethylene (ODE) with CO 2 as oxidant was carried out on these catalysts in a fixed-bed reactor at temperatures in the range of 600-700°C and at atmospheric pressure. The changes in structural and textural properties because of sulfate modification were identified. Sulfate modification affected the nature of interaction of CrO x species with the SBA-15 support. During the evaluation, it was observed that sulfate modification enhances ethane conversion and ethylene selectivity of the catalyst. Better dispersion of CrO x and the increase in Cr 6? /Cr 3? ratio seem to be the reasons for the higher performance of the sulfate-modified catalysts compared to that of the unmodified catalyst.

Atomically synergistic Zn-Cr catalyst for iso-stoichiometric co-conversion of ethane and CO2 to ethylene and CO

“…The Zn 3 Cr 1 /SSZ-13 ABC catalyst displayed the best performance among all tested catalysts, with the highest C 2 H 6 conversion (19.8%), CO 2 conversion (18.7%), turnover frequency (TOF) of C 2 H 4 formation (0.77 mol mol Zn+Cr −1 h −1 ), as well as excellent C 2 H 4 selectivity (93.0%) and (94.4%). Previous studies have mainly focused on achieving high ethane conversion and ethylene selectivity in co-conversion of ethane and CO 2 by co-feeding excess CO 2 at CO 2 /ethane ratios of 2–6 49 – 53 . In the ICEC process the C 2 H 4 selectivity and are two important factors for evaluating the success of catalyst development.…”

Advanced zeolite and ordered mesoporous silica-based catalysts for the conversion of CO2to chemicals and fuels

“…Accordingly, a chromium sulfate modified SBA-15 material with 6% sulfate and 5% Cr (5 wt% Cr/S-SBA-15) was prepared by impregnation. 1076 TEM images indicated that sulfation induced a higher and homogeneous dispersion of Cr species in the monolayer and with smaller particle size, while XPS and Raman spectra revealed an increase of the Cr 6+ /Cr 3+ ratio after sulfate modification which drastically influenced the catalytic activity. The TPR profile showed a shift of the reduction peak towards higher temperature, attributed to stronger interaction between Cr species and SBA-15, leading to higher dispersion.…”

A Low Carbon Route to Ethylene: Ethane Oxidative Dehydrogenation with Co2 on Embryonic Zeolite Supported Mo-Carbide Catalyst

“…For the ODH-CO 2 reaction, precious metals, oxide [31], and carbide [30]-based catalysts are reported. Most of the catalytic systems are based on Pt [32], Ni [33], Co [34], Cr [35,36], Fe [37] oxides deposited on zeolite or oxide carriers.…”