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

An important strategy for the reduction of levels of CO2 in the atmosphere is to utilize this greenhouse gas as a reagent molecule in catalytic reactions for the synthesis of widely used chemical products. CO2 utilization is therefore the "chemical fixation" of this greenhouse gas and should therefore be considered as an integral part of atmospheric carbon dioxide management because such chemical conversion can not only add value to CO2 capture and sequestration but also have economic societal and environmental benefits. Here, we investigate the use of high-performance catalysts for the dehydrogenation of propane by CO2 to the industrially important 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 different catalyst morphologies, structures, and catalytic properties as compared to the widely used "impregnation" synthesis protocol. The one-pot synthesis method provides a more uniform and highly dispersed catalytically active phase in which and the Cr species are more effectively involved in the dehydrogenation process. The introduction of Ca oxide as a promoter in the catalytic process increases both the overall propane dehydrogenation conversion and propylene selectivity and, importantly, also reduces the level of detrimental carbon deposition on the catalyst particles leading to enhanced stability and performance.