Facile synthesis of pure monoclinic and tetragonal zirconia   nanoparticles and their phase effects on the behavior of supported   molybdena catalysts for methanol-selective oxidation

doi:10.1021/la800370r

CORC > 北京大学 > 化学与分子工程学院

	Facile synthesis of pure monoclinic and tetragonal zirconia nanoparticles and their phase effects on the behavior of supported molybdena catalysts for methanol-selective oxidation
	Li, Weizhen ; Huang, Hua ; Li, Hongjia ; Zhang, Wei ; Liu, Haichao
刊名	langmuir
	2008
关键词	OXIDE CATALYSTS SURFACE-AREA ZRO2 RAMAN TRANSFORMATION STABILIZATION MORPHOLOGY STABILITY EVOLUTION ETHANOL
DOI	10.1021/la800370r
英文摘要	Pure monoclinic (m) and tetragonal (t) zirconia nanoparticles were readily synthesized from the reaction of inorganic zirconium salts (e.g., hydrated zirconyl nitrate) and urea in water and methanol, respectively, via a facile solvothermal method. The role of the solvents was crucial in the formation of the pure ZrO2 phases, whereas their purity was essentially insensitive to other variables, including reaction temperature, reactant concentration, pH, and zirconium salts. Water as the solvent led to the transformation of hydrous ZrO2 precipitates initially formed with tetragonal structures to thermodynamically more stable m-ZrO2 via the dissolution-precipitation process, whereas methanol favored the removal of water molecules from the precursors via their reaction with urea, consequently maintaining the tetragonal structures. The obtained tetragonal samples were found to possess superior hydrothermal stability compared to those reported previously, which provides the possibility for systematically studying the effects of ZrO2 phases on many catalytic reactions involving water as a reactant or product. Using these pure m- and t-ZrO2 phases as supports, dispersed MoO, catalysts were synthesized at MoOx surface densities of similar to 5.0 Mo/nm(2), which is close to one monolayer of coverage. Characterization by X-ray diffraction and Raman spectroscopy confirmed that the pure ZrO2 phases remained unchanged in the presence of the MoOx domains and the MoO. domains existed preferentially as 2D polymolybdate structures. The catalysts were subsequently examined for selective methanol oxidation as a test reaction. m-ZrO2 support led to 2-fold greater oxidation rates than for t-ZrO2 support, reflecting the higher intrinsic reactivity of the MoO, domains on m-ZrO2. This is consistent with their higher reducibility probed by temperatureprogrammed reduction with H-2 (H-2 TPR). These observed effects of the ZrO2 phases provide the basis for designing catalysts with tunable redox properties and reactivity.; http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000258034500102&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701 ; Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary; SCI(E); EI; 58; ARTICLE; 15; 8358-8366; 24
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/262599]
专题	化学与分子工程学院
推荐引用方式 GB/T 7714	Li, Weizhen,Huang, Hua,Li, Hongjia,et al. Facile synthesis of pure monoclinic and tetragonal zirconia nanoparticles and their phase effects on the behavior of supported molybdena catalysts for methanol-selective oxidation[J]. langmuir,2008.
APA	Li, Weizhen,Huang, Hua,Li, Hongjia,Zhang, Wei,&Liu, Haichao.(2008).Facile synthesis of pure monoclinic and tetragonal zirconia nanoparticles and their phase effects on the behavior of supported molybdena catalysts for methanol-selective oxidation.langmuir.
MLA	Li, Weizhen,et al."Facile synthesis of pure monoclinic and tetragonal zirconia nanoparticles and their phase effects on the behavior of supported molybdena catalysts for methanol-selective oxidation".langmuir (2008).