Combination of Experimental and Theoretical Investigations of MnOx/Ce0.9Zr0.1O2 Nanorods for Selective Catalytic Reduction of NO with Ammonia

详细信息    查看全文

• 作者：Phornphimon Maitarad ; Dengsong Zhang ; Ruihua Gao ; Liyi Shi ; Hongrui Li ; Lei Huang ; Thanyada Rungrotmongkol ; Jianping Zhang
• 刊名：The Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：May 16, 2013
• 年：2013
• 卷：117
• 期：19
• 页码：9999-10006
• 全文大小：539K
• 年卷期：v.117,no.19(May 16, 2013)
• ISSN：1932-7455

文摘

Manganese oxides (MnO_x) supported on Ce_0.9Zr_0.1O₂ (MnO_x/Ce_0.9Zr_0.1O₂) nanorods were synthesized and tested for low-temperature selective catalytic reduction of NO with ammonia. The catalysts were characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and hydrogen temperature-programmed reduction. The structure and morphology results show that the MnO_x was highly dispersed on the surface of Ce_0.9Zr_0.1O₂ nanorods. Various species, such as Mn²⁺, Mn³⁺, and Mn⁴⁺, were exposed due to a strong interaction between manganese and cerium oxides. Thus, the MnO_x/Ce_0.9Zr_0.1O₂ nanorods exhibited a better catalytic performance (90% NO conversion at 150 掳C) compared with that of the as-prepared Ce_0.9Zr_0.1O₂ nanorods. Density functional theory (DFT) calculations clearly demonstrated that the MnO_x on the surface of supporting nanorods or Mn@CeO₂(110) could easily form an oxygen vacancy distortion. Furthermore, the Mn@CeO₂(110) model in the DFT analysis showed a prominent effect on the NO and NH₃ adsorption which resulted in a stronger nitrite intermediate (NOO*) formation and more attractive interaction with the NH₃ gas compared with those observed with the CeO₂(110) model. Therefore, a thorough understanding of the structure and catalytic performance of MnO_x/Ce_0.9Zr_0.1O₂ nanorods was successfully achieved by a combination of experimental and theoretical studies.