No abstract

MnÀ Ni oxides supported on ordered mesoporous alumina (OMA) catalysts were applied to the NH 3 À SCR of NO x at lowtemperature compared with MnÀ Ni oxides supported on commercial γ-Al 2 O 3 . The NO x conversion and N 2 selectivity of MnÀ Ni/OMA were superior to the MnÀ Ni/γ-Al 2 O 3 in the temperature window of 90~240°C. BET, XRD, NH 3 À TPD, NO + O 2 À TPD, Pyridine-IR, H 2 À TPR, and XPS were performed to characterized the physicochemical properties of the catalysts. The characterization results manifested that supports conduct a significant part on the structural and catalytic properties of catalysts for NH 3 À SCR performance. Compared with MnÀ Ni/Al 2 O 3 , the super SCR performances of MnÀ Ni/OMA could be ascribed to not only the higher dispersion of MnO x but also more abundant Lewis acid sites, and the increase in redox capacity since the extremely primary MnO 2 phase on catalyst's surface. Furthermore, in situ DRIFTs were conducted to detect the SCR-reaction mechanism over the two catalysts. Results demonstrate that although the OMA support can greatly enhance the catalytic activity of MnÀ Ni/OMA catalysts, the reaction mechanism over MnÀ Ni/OMA does not alter in comparison with MnÀ Ni/Al 2 O 3 . Namely, the concurrence of Langmuir-Hinshelwood (LÀ H) and Eley-Rideal (EÀ R) mechanism, among which the EÀ R mechanism plays a dominant role.[a] Dr.

No abstract

No abstract