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.