Structure鈥揂ctivity Relationships of NiO on CeO2 Nanorods for the Selective Catalytic Reduction of NO with NH3: Experimental and DFT Studies

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• 作者：Phornphimon Maitarad ; Jin Han ; Dengsong Zhang ; Liyi Shi ; Supawadee Namuangruk ; Thanyada Rungrotmongkol
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：May 8, 2014
• 年：2014
• 卷：118
• 期：18
• 页码：9612-9620
• 全文大小：620K
• 年卷期：v.118,no.18(May 8, 2014)
• ISSN：1932-7455

文摘

CeO₂ nanorods impregnated with 2.5 atom % of NiO (NiO/CeO₂ nanorods) were successfully synthesized and examined as catalysts for the NH₃-selective catalytic reduction (NH₃-SCR) of nitric oxide (NO). The catalytic activity of NiO/CeO₂ nanorods resulted in up to 90% NO conversion at 250 掳C, which is superior to that of pure CeO₂ nanorods or NiO nanoparticles. Subsequently, extensive studies of the NiO/CeO₂-catalyzed reduction of NO were conducted using X-ray photoelectron spectroscopy, hydrogen temperature-programmed reduction, temperature-programmed desorption, and density functional theory periodic calculations. Compared to that of the pure CeO₂ nanorods, the results demonstrated that the NiO/CeO₂ nanorods resulted in (i) a higher concentration of Ce³⁺ chemical species, (ii) a larger amount of active O_伪, (iii) lower temperature reducibility, (iv) a lower amount of energy required for oxygen vacancy distortion, and (v) a significant adsorption of and strong interaction between NO and NH₃ molecules. Our findings therefore elucidated considerable details of the structural properties of the NiO/CeO₂ nanorods that were decisive for achieving a highly efficient conversion of NO by the NH₃-SCR process at low temperatures.