A series of CuO-based catalysts supported on the α-MnO₂ nanowire were facilely synthesized and employed as the CO oxidation catalysts. The achieved catalysts were systematically characterized by XRD, SEM, EDS-mapping, XPS and H₂-TPR. The catalytic performances toward CO oxidation had been carefully evaluated over these CuO-based catalysts. The effects of different loading methods, calcination temperatures and CuO loading on the low temperature catalytic activity of the catalyst were investigated and compared with the traditional commercial MnO₂ catalyst with a block structure. It was found that the slenderness ratio of a CuO/α-MnO₂ nanowire catalyst decreases with the increase in CuO loading capacity. The results showed that when CuO loading was 3 wt%, calcination temperature was 200 °C and the catalyst that was supported by the deposition precipitation method had the highest catalytic activity. Besides, the α-MnO₂ nanowire-supported catalysts with excellent redox properties displayed much better catalytic performances than the commercial MnO₂-supported catalyst. In conclusion, the CuO-based catalysts that are supported by α-MnO₂ nanowires are considered as a series of promising CO oxidation catalysts.

The Ni-based catalysts have a wide range of industrial applications due to its low cost, but its activity of CO₂ methanation is not comparable to that of precious metal catalysts. In order to solve this problem, Ni-based mesoporous Ce_0.8Zr_0.2O₂ solid solution catalysts doped with rare earth were prepared by the incipient impregnation method and directly used as catalysts for the methanation of CO₂. The catalysts were characterized systematically by X-ray powder diffraction (XRD), N₂ physisorption, transmission electron microscopy (TEM), energy-dispersed spectroscopy (EDS) mapping, X-ray photoelectron spectroscopy (XPS), H₂ temperature programmed reduction (H₂-TPR), CO₂ temperature programmed desorption (CO₂-TPD), and so on. The results show that Ni is highly dispersed in the mesoporous skeleton, forming a strong metal-skeleton interaction. Therefore, under the condition of CO₂ methanation, the hot sintering of metallic Ni nanoparticles can be effectively inhibited so that these mesoporous catalysts have good stability without obvious deactivation. The rare earth doping can significantly increase the surface alkalinity of catalyst and enhance the chemisorption of CO₂. In addition, the rare earth elements also act as electron modifiers to help activate CO₂ molecules. Therefore, the rare earth doped Ni-based mesoporous Ce_0.8Zr_0.2O₂ solid solution catalysts are expected to be an efficient catalyst for the methanation of CO₂ at low-temperature.