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TiO2–graphene (TiO2–GE) nanocomposites were prepared by the sol–gel method with different mass ratios of graphene (0–2% wt %). With the MnO X active component loaded by means of ultrasonic impregnation, the catalysts exhibited excellent structure and electrical properties, which favored the catalytic reaction. All the catalysts were characterized by XRD, SEM, TEM, BET, FT-IR, XPS, and Raman spectroscopy. The results indicated that the reduction of graphene oxide and formation of graphene in TiO2–GE supports and TiO2–graphene were readily indexed to anatase TiO2 in all samples. Various valences of manganese species coexisted in MnO X /TiO2–GE catalysts. Especially, nonstoichiometric MnO X /Mn on the surface of composite catalyst was beneficial to the electron transfer; therefore, the redox performance of the catalyst was improved. The MnO X /TiO2–0.8%GE catalyst exhibited good resistance to simultaneous H2O and SO2, as well as to only H2O, with an optimum Mn mass ratio of 7 wt %. All the samples showed excellent N2 selectivity.

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Abstract:A series of 9%CeO x -MnO x /TiO 2 -GO nanocomposites with different molar ratios of Ce/Mn were synthesized by the sol-gel and ultrasonic impregnation methods and characterized by field emission scanning electron microscope (FESEM), high resolution transmission electron microscopy (HRTEM), N 2 adsorption (BET) analysis, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FT-IR). The results showed that various valences of Ce and Mn oxides were uniformly distributed on the surface of TiO 2 -GO multilayered supports. The coexistence of various valences of Ce and Mn oxides can improve the redox performance of the catalyst. With the introduction of Ce, the amount of MnO 2 and non-stoichiometric MnO x /Mn, the total oxygen and chemisorbed oxygen content, and the electron transfer ability of the catalyst increased significantly. When the molar ratio of Ce/Mn was 0.3, the catalysts exhibited high selective catalytic reduction activity (more than 99% at 180 • C) and N 2 selectivity. The presence of hydrophilic groups on the surface of the GO was considered as the critical factor influencing the H 2 O resistance of the catalyst. Due to the pre-sulfuring process of GO, serious sulfation of the active component can be prevented, and the catalyst exhibited excellent SO 2 resistance.