Heavy metals impregnated TiO2 catalysts for the multi-pollution reduction of coal-fired flue gas

作者：Chen, Yin; Liao, Yanfen^*; Chen, Lin; Chen, Shunkai; Chen, Zhuofan; Ma, Xiaoqian

来源：Journal of Environmental Chemical Engineering, 2021, 9(5): 105822.

DOI：10.1016/j.jece.2021.105822

• Air pollutants
• NH3-SCR
• VOCs
• Mechanism
• Green environment

The synergistic conversion of VOCs and NO in SCR region of power plants is still a challenge and its catalytic redox mechanism needs to be further understood. Heavy metal oxide loading can effectively expand the lowtemperature VOCs and NO potency of catalysts. Here, a series of single heavy metal oxide (CeOX, CrOX, and MnOX) modified TiO2 catalysts were prepared to study their performance of removing VOCs (benzene and toluene) and NO between 260 degrees C and 420 degrees C. The catalytic potency was thoroughly investigated, and their physicochemical properties were assessed by a variety of instruments. Performance evaluation of catalysts found that CrOX/TiO2 achieved over 99% VOCs removal and 78.20% denitration efficiency at 340 degrees C, which was hopeful to be applied to industrial SCR areas. The excellent performance of CrOX/TiO2 should be attributed to the strong redox capacity and abundant surface active oxygen. Also, the in-situ DRIFTS results verified that the NH3SCR reaction of CrOX/TiO2 catalyst at 340 degrees C was governed by the combination of the Eley-Rideal mechanism and the Langmuir-Hinshelwood mechanism. More importantly, it confirmed that alkoxides, benzoates, and anhydrides are the main intermediates, indicating that the reaction pathway may be as follows: benzene -> benzoquinone ->center dot center dot center dot CO2 and H2O, and toluene -> benzyl alcohol -> benzaldehyde -> benzoic acid ->center dot center dot center dot -> CO2 and H2O.