The CeOX and MnOX nanocrystals supported on TiO2-graphene oxide catalysts and their selective catalytic reduction properties at low temperature

Abstract

A series of 9%CeOx-MnOx/TiO2-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), N2 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 TiO2-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 MnO2 and non-stoichiometric MnOx/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 N2 selectivity. The presence of hydrophilic groups on the surface of the GO was considered as the critical factor influencing the H2O 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 SO2 resistance.