Chromium oxide supported on MCM-41 as a highly active and selective catalyst for dehydrogenation of propane with CO2 Original Research Article

Incipient wetness technique was used for a preparation of MCM-supported chromium oxide materials with a Cr loading ranging from 0.7 to 13.7 wt%. The obtained samples were characterized by XRD, UV–vis-DRS, H2-TPR and BET, and tested as catalysts in dehydrogenation of propane with CO2. The catalytic reaction was studied in a flow apparatus at 773–923 K. All the tested catalysts exhibited a good catalytic performance in the dehydrogenation of propane with CO2. The best results were achieved over the sample containing 6.8 wt% of Cr. In this case, the selectivity to propene was above 80%, while the conversion of propane increased from 21% (at 773 K) to 62% (at 923 K). The promoting effect of CO2 on the yield of propene was found for all the studied catalysts. This effect was discussed on the basis of temperature-programmed reaction of CO2 with H2 as well as H2-TPR experiments after regeneration of the reduced catalyst with pure CO2. It was suggested that one of reasons of a higher yield of propene observed in the presence of CO2 compared to that measured in the absence of CO2 was coupling of the dehydrogenation of propane with the reverse water–gas shift reaction.