Oxidative dehydrogenation and dry reforming of n-butane with CO2 over NiFe bimetallic catalysts

The oxidative dehydrogenation of n-butane to 1,3-butadiene using CO2 as a soft oxidant is investigated over oxide-supported NiFe bimetallic catalysts. Dry reforming of n-butane with CO2 to syngas is also studied under identical conditions for comparison. The Ni(1)ire(3)/CeO2 catalyst is identified as a promising catalyst for the oxidative dehydrogenation to 1,3-butadiene via the C-H bond cleavage, while the Ni3Fe1/CeO2 catalyst mainly promotes the dry reforming pathway via the C-C bond scission. The oxidation states of Ni and Fe are determined by X-ray absorption fine structure (XAFS) measurements under reaction conditions. Density functional theory (DFT) calculations are performed to further understand the different reaction pathways. Furthermore, the effect of oxide supports is studied for the Ni1Fe3 bimetallic catalysts, showing that highly reducible supports, CeO2 and CeO2-ZrO2, promote the production of 1,3-butadiene, whereas the ZrO2 support significantly suppresses the oxidative dehydrogenation.