CuO-CeO₂ nanocatalysts with varying CuO contents (1, 5, 9, 14 and 17 wt %) were prepared by one-step flame spray pyrolysis (FSP) and applied to CO oxidation. The influences of CuO content on the as-prepared catalysts were systematically characterized by X-ray diffraction (XRD), N₂ adsorption-desorption at −196 °C, field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and hydrogen-temperature programmed reduction (H₂-TPR). A superior CO oxidation activity was observed for the 14 wt % CuO-CeO₂ catalyst, with 90% CO conversion at 98 °C at space velocity (60,000 mL × g⁻¹ × h⁻¹), which was attributed to abundant surface defects (lattice distortion, Ce³⁺, and oxygen vacancies) and high reducibility supported by strong synergistic interaction. In addition, the catalyst also displayed excellent stability and resistance to water vapor. Significantly, in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS) showed that in the CO catalytic oxidation process, the strong synergistic interaction led readily to dehydroxylation and CO adsorption on Cu⁺ at low temperature. Furthermore, in the feed of water vapor, although there was an adverse effect on the access of CO adsorption, there was also a positive effect on the formation of fewer carbon intermediates. All these results showed the potential of highly active and water vapor-resistive CuO-CeO₂ catalysts prepared by FSP.

A series of nanocrystalline copper–manganese oxides (denoted as Cu_3−xMn_x, x = 0, 1, 1.5, 2, 2.5, 3, where x means the molar ratio of Cu and Mn) were successfully prepared by a facile citric acid sol–gel method. The combination of Cu²⁺ and Mn³⁺ is intensified and enhanced interface effects generated, which is beneficial for the catalytic oxidation of benzene. A series of analyses, such as X-Ray Diffraction (XRD), N₂ adsorption–desorption, X-ray photoelectron spectroscopy (XPS), and hydrogen temperature programmed reduction (H₂-TPR), were employed to further investigate the structural properties of the catalysts. An optimal Mn/Cu ratio of 2 forms CuMn₂O₄ spinels. CuMn₂ with CuMn₂O₄ spinel structure presents a larger specific surface area, smaller pore diameter as well as more lattice oxygen species, exhibiting remarkable activity and stability for the catalytic oxidation of benzene. On account of these factors, CuMn₂ possesses better low temperature reducibility and shows the best catalytic performance with 90% benzene conversion at 186 °C. The enhanced catalytic activity of CuMn₂ is attributed to the stabilization of CuMn₂O₄ active phases and the intensive synergistic effect between Cu–Mn oxides. To prove the effect of CuMn₂O₄ spinel structure on catalytic performance, a CuO/Mn₂O₃ mixed catalyst (molar ratio 1 : 1) was prepared and applied to benzene oxidation (T_90% = 198 °C), which indicates that the spinel structure has an encouraging effect on benzene catalysis. The catalytic properties of single copper oxide and manganese trioxide were also tested, the results show that CuMn₂O₄ has a crucial role in facilitating electronic transmission and mobility of the lattice oxygen.

The synergetic effect is promoted on Mn doped CuO–Ce O₂ catalyst to induce less carbon intermediates to enhance CO oxidation performance.

Porous ceramic membranes (PCMs) are considered as an efficient hot gas filtration material in industrial systems. Functionalization of the PCMs with high-efficiency catalysts for the abatement of volatile organic compounds (VOCs) during dust elimination is a promising way to purify the industrial exhaust gases. In this work, we prepared PCMs (porosity: 70%) in a facile sintering process and integrated Cu-doped Mn–Ce oxides into the PCMs as monolithic catalysts by the sol–gel method for benzene oxidation. Through this method, the catalysts are dispersed evenly throughout the PCMs with excellent adhesion, and the catalytic PCMs provided more active sites for the reactant gases during the catalytic reaction process compared to the powder catalysts. The physicochemical properties of PCMs and catalytic PCMs were characterized systematically, and the catalytic activities were measured in total oxidation of benzene. As a result, all the prepared catalytic PCMs exhibited high catalytic activity for benzene oxidation. Significantly, the monolithic catalyst of Cu_0.2Mn_0.6Ce_0.2/PCMs obtained the lowest temperature for benzene conversion efficiency of 90% (T₉₀) at 212 °C with a high gaseous hourly space velocity of 5000 h⁻¹ and showed strong resistance to high humidity (90 vol.%, 20 °C) with long-term stability in continuous benzene stream, which is caused by abundant active adsorbed oxygen, more surficial oxygen vacancy, and lower-temperature reducibility.

A novel solution deposition process has been developed to prepare thin crystalline ZrO₂ layers on particle surfaces. The thickness and morphology of the ZrO₂ layers can be controlled by using surfactants under different reaction conditions. A needle-shaped monoclinic ZrO₂ array was formed by a multi-step deposition process with surfactants. Hollow ZrO₂ capsules that were obtained by dissolving the nanoparticle cores exhibited obvious photocatalytic properties for the degradation of Rhodamine B. This is a general process that can form crystalline layers coated on matrix core particles in solution.