Catalytic Hydrogenation Reactions on Molybdenum Oxide

• 作者: A. Katrib A. M. Mohamed F. Al-Kharafi H. Al-Kandari S. Al-Kandari
• 来源期刊: 催化剂现代研究(英文)
• 学科: 化学
• 关键词: MoO2-x(OH)y CATALYST XPS Acid-Metal FUNCTIONS HYDROGENATION 2-Propanol
• 年，卷（期）: 2015,（1）
• 页码范围: 36-42
• 页数: 7页
• 分类号: O6

摘要

Partially reduced molybdenum trioxide deposited on titania under hydrogen at 673 K for 12 h ena- bled to convert several surface atomic layers to the catalytically active bifunctional (metal-acid) MoO2-x(OH)y/TiO2 (MoTi) structure. The formed metallic function is the result of π bonding between adjacent Mo-Mo atoms placed along the C-axis of the rutile structure of MoO2. Delocalization of these π electrons produces a wire like atomic metal. This resembles in a way, the small Pt particles deposited on a support. Moreover, dissociated hydrogen atoms are bonded to sample surface oxygen to produce Brønsted acid Mo-OH function(s). These metal-acidic properties have been tested for several catalytic reactions requiring one or bothcatalytic functions. In this order, 2-propanol species could be considered as a model test of the acidic function via dehydration of the molecule to propene, while hydrogenation of the produced propene to propane is performed by the metallic function. Moreover, hydrogenation of 2-propanol to acetone, requires relatively strong metallic function. In this order, addition of small amount of alkali metal like rubidium will suppress the acidic function in MoO2-x(OH)y/TiO2 and enhance the metallic function strength. The performance of the metallic function alone in this case will be evaluated. Titanium dioxide is employed in this catalytic system as a support. It does not have any catalytic effect. Association of XPS-UPS, ISS sur-face techniques with catalytic performances of this catalytic MoTi system will be presented.