期刊
JOURNAL OF CATALYSIS
卷 276, 期 1, 页码 24-37出版社
ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI: 10.1016/j.jcat.2010.08.012
关键词
Selective oxidation; Methanol; Formaldehyde; Fe3-x-yVx square O-y(4) catalysts; Fe-V-O spinel type phases; Volatility; HRTEM; In situ XANES; XPS; XRD
资金
- The Swedish Research Council (VR)
- The Knut and Alice Wallenberg Foundation
- Lund University Sweden
A series of spinel-type Fe-V-O phases were prepared with V/Fe atomic ratios ranging from 0 to 1 and were used for methanol oxidation to formaldehyde X-ray powder diffraction shows that the basic spinel-type structure is retained after use of the samples in methanol oxidation Compared with the freshly prepared samples m- and ex situ analyses of the samples with XANES show that both V and Fe are oxidized under influence of methanol oxidation where octahedrally coordinated V3+ partially is oxidized to V4+ Simultaneously partial oxidation occurs of Fe2+ in tetrahedral and octahedral coordinations to form Fe3+. species XPS reveals that in general the surfaces with predominantly V5+ and Fe3+ species are more oxidized compared to the bulk Besides XRD HRTEM imaging confirms that the basic spinel type structure is stable in methanol oxidation Consequently the structure is very flexible allowing the cations to change oxidation state by forming canon vacancies without structural breakdown All preparations show activity of similar magnitude although great differences in selectivity to formaldehyde The best performing spinel catalyst is poor in vanadium with a V/Fe ratio of 1/14 indicating that isolated vanadia moieties perform better than polymeric vanadia structures The stable and flexible structure makes the spinel-type Fe-V-0 catalysts an interesting alternative to the presently used industrial catalyst consisting of a mixture of MoO3 and ferric molybdate Opposed to the industrial catalyst which suffers from Mo volatilization the spinel samples show no measurable volatilization of vanadium (C) 2010 Elsevier Inc All rights reserved
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据