Chromium catalysts supported on carbon nanotubes and graphene nanoflakes for CO2-assisted oxidative dehydrogenation of propane

CO2-assisted oxidative dehydrogenation of propane (ODP) is a promising approach for addressing two great modern challenges: effective CO2 utilization and propylene synthesis. In this work different carbon materials were for the first time used as supports for Cr-based catalysts of CO2-assisted ODP. Carbon nanotubes (CNTs), jellyfish-like graphene nanoflakes (GNFs), and their oxidized and N-doped derivatives were tested and compared with a commercial activated carbon. The best activities and propylene yield up to 25% were observed for the oxidized CNT- and pristine GNF-supported catalysts. The stability of these two catalysts against destruction and particle sintering during tests was confirmed by Raman spectroscopy. High activity and stability of the oxidized CNT- and pristine GNF-supported catalysts was explained by their macro- and mesoporosity that enhance diffusion of reagents and products and by the highest surface graphitization degree confirmed by XPS. These catalysts showed much better performance than the activated carbon-supported catalyst. Therefore, GNFs and CNTs can be considered as effective supports of the CO2-ODP catalysts.