Submonolayer Vanadium and Manganese Binary Metal Oxides Supported on Three-Dimensionally Ordered Mesoporous CeO2 for Efficient Low-Temperature NH3-SCR

Submonolayer-supported catalysts exhibited excellent activity for ammonia selective catalytic reduction (NH3-SCR) and have attracted great interest. Here, a catalyst based on three-dimensional ordered mesoporous (3DOM) CeO(2)supported by a submonolayer of vanadium and manganese bimetal oxides (3DOM VOx-MnOx/CeO2) was successfully synthesized. The optimal catalytic temperature was found to shift to lower temperature with increasing VOx-MnOx loading amount under the submonolayer coverage. The 5 wt% 3DOM VOx-MnOx/CeO2 catalyst with submonolayer coverage exhibited the best catalytic performance, achieving a NO conversion of more than 95% at 250 degrees C. It was found that three-dimensional CeO2 endowed the material with a high specific surface and highly ordered mesoporous channels, which could highly disperse VOx-MnO(x)below one monolayer coverage. Based on NH3-TPD, H-2-TPR, Raman and XPS characterization, an increase in VOx-MnOx content under the submonolayer coverage resulted in an enhancement of the surface acidity, redox capacity, number of oxygen vacancy defects and charge transfer. In particular, the 5 wt% 3DOM VOx-MnOx/CeO2 catalyst showed the highest number of acidic sites that for NH3 activation and the fastest electron transfer required for oxygen to be regenerated. Therefore, the 5 wt% 3DOM VOx-MnOx/CeO2 catalyst with submonolayer coverage generated a significantly enhanced catalytic performance, which made it desirable for NO removal applications. [GRAPHICS] .

Automated summary

Submonolayer-supported catalysts based on 3DOM CeO(2) loaded with VOx-MnOx exhibit excellent activity for NH3-SCR, with the 5 wt% 3DOM VOx-MnOx/CeO2 catalyst showing the best catalytic performance achieving over 95% NO conversion at 250 degrees C.