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

• Published in: Catalysis letters 2021-05, Vol.151 (5), p.1385-1396
• Main Authors: Chen, Ziyi, Wu, Xiaomin, Yang, Boyin, Huang, Zhiwei, Shen, Huazhen, Jing, Guohua
• Format: Article
• Language: English
• Subjects: Ammonia; Bimetals; Catalysis; Catalysts; Catalytic converters; Cerium oxides; Charge transfer; Chemical reduction; Chemical synthesis; Chemistry; Chemistry and Materials Science; Electron transfer; Industrial Chemistry/Chemical Engineering; Low temperature; Manganese; Metal oxides; Organometallic Chemistry; Physical Chemistry; Selective catalytic reduction; Vanadium; X ray photoelectron spectroscopy
• ISSN: 1011-372X; 1572-879X
• DOI: 10.1007/s10562-020-03387-6

Submonolayer-supported catalysts exhibited excellent activity for ammonia selective catalytic reduction (NH 3 –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 VO x –MnO x /CeO 2 ) was successfully synthesized. The optimal catalytic temperature was found to shift to lower temperature with increasing VO x –MnO x loading amount under the submonolayer coverage. The 5 wt% 3DOM VO x –MnO x /CeO 2 catalyst with submonolayer coverage exhibited the best catalytic performance, achieving a NO conversion of more than 95% at 250 °C. It was found that three-dimensional CeO 2 endowed the material with a high specific surface and highly ordered mesoporous channels, which could highly disperse VO x –MnO x below one monolayer coverage. Based on NH 3 –TPD, H 2 –TPR, Raman and XPS characterization, an increase in VO x –MnO x 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 VO x –MnO x /CeO 2 catalyst showed the highest number of acidic sites that for NH 3 activation and the fastest electron transfer required for oxygen to be regenerated. Therefore, the 5 wt% 3DOM VO x –MnO x /CeO 2 catalyst with submonolayer coverage generated a significantly enhanced catalytic performance, which made it desirable for NO removal applications. Graphic Abstract