Carbon dioxide reduction in tandem with light-alkane dehydrogenation

A greenhouse gas and mild oxidant, CO2 can effect the oxidative dehydrogenation (CO2-ODH) of light alkanes over heterogeneous catalysts. These catalysts are bifunctional in that they mediate CO2 reduction while oxidizing the alkanes, most notably the C-2-C-4 components in shale gas. In this way, one obtains CO and alkenes as value-added products. Although desirable, this transformation has proven challenging in terms of catalyst design, with most catalysts for the CO2-ODH being metal oxides that typically undergo rapid deactivation. More recently, bimetallic catalysts have been identified as promising systems to activate alkanes by either selectively cleaving C-H bonds to produce alkenes or breaking all the C-C and C-H bonds to produce the dry reforming products CO and H-2. This Review describes general trends in the CO2-ODH of light alkanes. We will also outline how to use a combined approach involving flow reactor experiments, in operando characterization and density functional theory to determine whether a catalyst is intrinsically active for CO2-ODH or dry reforming.