One-Pot Synthesis of Ca Oxide-Promoted Cr Catalysts for the Dehydrogenation of Propane Using CO₂

Abstract

An important strategy for the reduction of levels of CO2 in the atmosphere is to utilise it as a reagent molecule in catalytic reactions for the synthesis of high-value chemical products. Here we investigate the use of high-performance catalysts for the dehydrogenation of propane by CO2 to the industriallyimportant molecule, propylene. Cr-based catalysts with a Ca oxide promoter on a ZrO2 support have been prepared using a "one-pot" synthesis procedure. A range of structural and spectroscopic techniques revealed that this synthetic procedure produces a different catalyst morphology and structure and catalytic properties as compared to the widely -used "impregnation" synthesis protocol.The one-pot synthesis method provides a more uniform and well-dispersed catalytically active phase and the Cr species then appear more effectively involved in the dehydrogenation process. The introduction of Ca oxide as a promoter in the catalytic process increases both the overall propane conversion and propylene selectivity and, importantly, also reduces the level of carbon deposition on the catalyst particles leading to enhanced stability and performance.

Light olefin synthesis from a diversity of renewable and fossil feedstocks: state-of the-art and outlook

“…Additional inhibition of carbon deposition can be also reached by promoting the catalyst by CaO, which increases both the conversion and the selectivity of ODH. 153 Al-Mamoori 154 et al proposed an interesting approach for CO 2 -ODH involving physically mixing of the Cr/H-ZSM-5 catalyst with a K-Ca oxide-carbonate mixture. The two-step process, in which the K-Ca component catches CO 2 , while the Cr catalyst dehydrogenates ethane, allowed achieving a selectivity to ethylene of 88% at the 25% ethane conversion.…”

Enhancing catalytic activity of Cr2O3 in CO2-assisted propane dehydrogenation with effective dopant engineering: a DFT-based microkinetic simulation

“…Due to the complex nature of CO 2 , most of the previous literature focuses on the chromium active site and its relation with performance. 15,[19][20][21] Previously, we have explored the direct and indirect effects of CO 2 in the PDH process. The CO 2 participates in the dehydrogenation process in adsorbed and dissociated forms.…”

A critical evaluation of the catalytic role of CO2 in propane dehydrogenation catalyzed by chromium oxide from a DFT-based microkinetic simulation

“…Among soft oxidants, CO 2 is the most widely examined one. 10,[12][13][14] The use of CO 2 as an oxidant not only improves the catalytic performance but also reduces the greenhouse gas emissions. Therefore, it is a win-win solution.…”

“…The available discussions of CO 2 are also showing contradictions. 5,12,19,26 The absence of a deep understanding of CO 2 catalytic capabilities has significantly hindered the resolution of the reaction mechanism and rational optimization.…”