Catalytic combustion of propane over Zr-modified Co₃O₄ catalysts: An experimental and theoretical study

As one of the domain volatile organic compounds (VOC), short chain alkane is an obstacle for low-temperature purification. Here, cobalt-zirconium oxides catalysts in a range of Co/Zr ratios were synthesized by sol-gel method for the catalytic combustion of propane. The result indicates that the catalyst with a ratio of Co to Zr of 4 (Co4Zr1) not only exhibits the superior catalytic performance with 90% conversion at 242 C, but also maintains high thermal stability and water resistance. The synergistic effect between Co and Zr over cobalt zirconium oxides catalysts contributes to the high increase of catalytic activity, which are relevant to the formation of ZrO2-Co3O4 solid solution. Additionally, the introduced Zr leads to more surface Co3+ species and surface-absorbed oxygen over Co4Zr1 catalyst. Moreover, high-resolution transmission electron microscopy (HRTEM) reveals Co4Zr1 catalyst exposes abundant (220) crystal face. Density functional theory (DFT) suggests that Co3O4 (220) shows lowest adsorption energy (-0.71 eV) and the formation of oxygen defects will reduce the adsorption energy (-1.03 eV). All these results confirm that the CoxZry catalysts are promising alternative for propane degradation and provide important guiding significance for the design of catalysts and catalytic combustion kinetics.