Synergistic Effect of Zinc and Iron in the CO₂-Assisted Oxidative Dehydrogenation of Propane

The CO2-assisted oxidative dehydrogenation (CO2-ODH) of C3H8 provides a promising process for producing C3H6 and utilizing CO2. In this study, the combination of zinc and iron demonstrated a synergistic effect, leading to improved catalytic activity and stability. The importance of the reducibility of ZnFe2Ox/S-1 has been highlighted through auxiliary experiments and comprehensive characterizations. The presence of sodium additives is found to hinder the reduction of ZnFe2Ox/S-1 by inducing strong interactions. Furthermore, during the initial stage of the reaction, the reduction process initiates the catalytic activity and promotes CO2 conversion through decarbonization reactions. The precursor of ZnFe2O4 and the strong interaction between Zn and Fe species, along with the formation process of alpha-Fe from inside to outside, effectively prevent the occurrence of the reforming reaction and suppress the coking deactivation of ZnFe2Ox/S-1. This study provides fundamental insights into Zn- and Fe-based catalysts in the CO2-assisted oxidative dehydrogenation reaction.