Co3O4-SiO2纳米复合材料:一种非常活跃的CO氧化催化剂,具有不寻常的催化行为
Chun-Jiang Jia1, Manfred Schwickardi, Claudia Weidenthaler
1Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany.
Journal of the American Chemical Society
|June 24, 2011
概括
一种新型的氧化物-酸盐催化剂在低温下对一氧化碳 (CO) 氧化具有异常活力. 催化剂表面的水吸附解释了异常的温度依赖活性,这是异质催化剂中罕见的现象.
科学领域:
- 材料科学 材料科学 材料科学
- 催化剂是一种催化剂.
- 表面化学 表面化学
背景情况:
- 一氧化碳 (CO) 的氧化对于环境修复和工业过程至关重要.
- 开发高效的CO氧化催化剂,特别是在低温下,仍然是一个重大挑战.
- 纳米复合材料为催化应用提供了独特的特性.
研究的目的:
- 为了合成和表征一个高表面积的氧化- (Co(3) O(4) -SiO(2)) 纳米复合材料催化剂.
- 为了研究CO氧化过程中Co(3) O(4) -SiO(2) 纳米复合物的催化活性.
- 为了了解观察到的催化剂的异常温度依赖活性.
主要方法:
- 使用活性炭作为模板制备Co(3) O(4) -SiO(2) 纳米复合材料.
- 对一系列温度范围内的CO氧化催化活性的评估.
- 在现场扩散反射里埃变换红外光谱 (DRIFT) 用于研究表面物种和吸附现象.
主要成果:
- 纳米复合材料Co(3) O(4) -SiO(2) 催化剂表现出非常高的CO氧化活性,即使在-76°C.
- 观察到一个不寻常的U形温度-活动曲线,在正常的料气体条件下,最低转换值约为80°C.
- 催化剂在特定温度范围内显示出负的明显激活能量,这是CO氧化催化剂中罕见的观察结果.
结论:
- Co(3) O(4) -SiO(2) 纳米复合材料是CO氧化的一种高度活跃的催化剂,特别是在低温下.
- 催化剂表面上水分子的吸附是观察到的异常温度依赖活动的原因.
- 现场DRIFT光谱学证实了水吸附在改变催化剂行为中的作用.
相关概念视频
Heterogeneous Catalysis
Heterogeneous catalysis involves a catalyst in a different phase from the reactants. It is a process where the catalyst and the reactants are in distinct phases, typically solid and gas or liquid.Most heterogeneous catalysts are metals, metal oxides, or acids. The list includes transition metals like iron (Fe), cobalt (Co), nickel (Ni), palladium (Pd), platinum (Pt), chromium (Cr), manganese (Mn), tungsten (W), silver (Ag), and copper (Cu). These metals possess partially vacant d orbitals that...
Catalysis
The presence of a catalyst affects the rate of a chemical reaction. A catalyst is a substance that can increase the reaction rate without being consumed during the process. A basic comprehension of a catalysts’ role during chemical reactions can be understood from the concept of reaction mechanisms and energy diagrams.
Catalysis
Catalysis influences the rate of chemical reactions by providing an alternative reaction pathway with lower activation energy. A catalyst speeds up a reaction, but it is not consumed during the process. The fundamental principle of catalysis is the ability of a catalyst to alter the reaction mechanism, often introducing a more efficient pathway than the uncatalyzed process.In a catalyzed reaction, the catalyst participates directly in the reaction mechanism. It interacts with reactants to form...

