Catalytic Oxidative Decomposition of Dimethyl Methyl Phosphonate over CuO/CeO2 Catalysts Prepared Using a Secondary Alkaline Hydrothermal Method

Abstract

Bimetallic synergism plays an important role in lattice-doped catalysts. Therefore, lattice-doped bimetallic CuO/CeO2 catalysts were prepared by secondary alkaline hydrothermal reaction. During this process, the CeO2 nanomaterials were partially dissolved and recrystallized; thus, Cu ions were doped into the CeO2 lattice. The physical and chemical properties of CeO2, CuO/CeO2, and CuO were investigated. H2 temperature-programmed reduction characterization showed that the oxidation activity of CuO/CeO2 was significantly improved. X-ray photoelectron spectroscopy results showed that electron transfer occurred between Ce and Cu in the CuO/CeO2 catalyst. Additionally, Raman characterization confirmed the strong interaction between Cu and Ce. After CuO was loaded, the thermal catalytic decomposition performance of the catalyst was significantly improved with respect to the sarin simulant dimethyl methyl phosphonate (DMMP); with an increase in the Cu/Ce ratio, the performance first strengthened and then weakened. Additionally, the reaction tail gas and catalyst surface products were analyzed using mass spectrometry and ion chromatography, and the changes in the surface products during the thermal catalytic decomposition of DMMP were characterized at different temperatures using in situ diffuse reflectance infrared Fourier transform spectroscopy. Finally, the catalytic reaction pathways of DMMP on CeO2, CuO/CeO2, and CuO were inferred. The study results not only demonstrate an effective catalyst for the removal of nerve agent but also a feasible preparation method for lattice-doped bimetallic catalysts in the field of environmental protection.