Fabrication of MnOx-CeO2/cordierite catalysts doped with FeOx and CuO for preferable catalytic oxidation of chlorobenzene

Improved activity and stability for chlorobenzene oxidation over ternary Cu-Mn-O-Ce solid solution supported on cordierite

A series of CuMnO_x/CeO₂/cordierite and CuMnCeO_x/cordierite catalysts prepared by a complex method with citric acid were investigated for the performance of chlorobenzene (CB) oxidation. The effects of the molar ratio of Mn/Cu, transition metal oxide loading, calcination temperature and time were investigated as the main investigation factor for the performance. Meanwhile, XRD, SEM, BET, H₂-TPR, O₂-TPD and XPS were conducted to characterize the physicochemical properties of these catalysts. The results demonstrated that CuMnO_x/CeO₂/cordierite catalysts prepared by step-by-step synthesis with the Cu/Mn molar ratio of 5:2 exhibited a high activity (T₉₀ = 350 °C), owing to the incorporation of CuO and MnO_x for forming CuMn₂O₄ spinel oxide supported on CeO₂ surface. More importantly, CuMnCeO_x/cordierite catalysts prepared by one-step exhibited the highest oxidation activity (T₉₀ < 300 °C) attributed to the low H₂ reduction temperature and desorption energy of surface oxygen, and the formed Cu-Mn-O-Ce solid solution and CeO₂ promoted the high dispersion of CuMnO_x in the supported catalysts. In addition, the possible oxidation mechanism was described to demonstrate the by-products generation and oxygen transfer of CuMnCeO_x catalysts.

Research Progress of a Composite Metal Oxide Catalyst for VOC Degradation

Volatile organic compounds (VOCs) are atmospheric pollutants that have been of concern for researchers in recent years because they are toxic, difficult to remove, and widely sourced and easily cause damage to the environment and human body. Most scholars use low-temperature plasma biological treatment, catalytic oxidation, adsorption, condensation, and recovery techniques to treat then effectively. Among them, catalytic oxidation technology has the advantages of a high catalytic efficiency, low energy consumption, high safety factor, high treatment efficiency, and less secondary pollution; it is currently widely used for VOC degradation technology. In this paper, the catalytic oxidation technology for the degradation of multiple types of VOCs as well as the development of a single metal oxide catalyst have been briefly introduced. We also focus on the research progress of composite metal oxide catalysts for the removal of VOCs by comparing and analyzing the metal component ratio, preparation method, and types of precursors and the catalysts' influence on the catalytic performance. In addition, the reason for catalyst deactivation and a correlation between the chemical state of the catalyst and the electron distribution are discussed. Development of a composite metal oxide catalyst for the catalytic oxidation of VOCs has been proposed.

Decomposition of gaseous chlorobenzene using a DBD combined CuO/α-Fe2O3 catalysis system

Copper oxide and hematite (CuO/α-Fe₂O₃) composite catalysts were prepared by using goethite as precursor adopted impregnation way and applied to the dielectric barrier discharge (DBD) catalytic decomposition of gaseous chlorobenzene. The CuO/α-Fe₂O₃ composite was characterised by X-ray diffraction, Brunauer-Emmett-Teller method, scanning electron microscopy and X-ray photoelectron spectrometer technique. The decomposition efficiency and energy yield of gaseous chlorobenzene in DBD catalysis system were studied by a function of gas flow rate, initial concentration and input voltage. The results showed that the CuO/α-Fe₂O₃ composite catalyst exhibited remarkable performance on chlorobenzene decomposition when the molar ratio was 0.4 and calcination temperature was 450°C. When the chlorobenzene initial concentration was 230 mg m^-3, the chlorobenzene decomposition efficiency and mineralisation rate on the DBD catalysis system reached 73.33% and 63.37%, respectively, its decomposition and mineralisation efficiency were enhanced about 20.5% and 16.61%, respectively, compared with the bare DBD system, and it also benefited to significantly reduce the ozone and NO₂ by-products. The possible pathway of chlorobenzene decomposition in the DBD catalytic hybrid system was proposed based on the products analysis.