在由支的金属集群催化的基化过程中观察连接物效应
1Department of Chemical Engineering and Materials Science, University of California, Davis 95616, USA.
Nature
|February 8, 2002
概括
支持的团通过从反应物中形成特定的配体来催化反应. 改变支材料,比如从MgO到gamma-Al2O3,通过改变连接体-支相互作用,显著增强了催化活性.
科学领域:
- 不同质的催化剂.
- 有机金属化学 有机金属化学
- 表面科学是一门科学.
背景情况:
- 同质的催化剂和酶通过金属协调激活反应物.
- 支金属集群的性能取决于支和吸附物.
- 支持影响通常归因于电子效应,忽视了化学结合.
研究的目的:
- 在催化过程中直接观察支的团结构.
- 为了识别烯化过程中形成的碳化合物配体.
- 了解在调整催化活动中的支和连接体之间的相互作用.
主要方法:
- 支持金属集群的直接结构观测.
- 使用光谱学识别连体物种.
- 用不同的支材料进行催化试验 (MgO与玛-Al2O3对比).
主要成果:
- 和H2在团上形成烯和化物连接体.
- 形成反应性中间体,削弱集群支持相互作用.
- 从MgO切换到玛-Al2O3支持增加了十倍的活性.
- 支持选择影响着联体结和联体丰度.
结论:
- 支金属集群的催化性能可以通过支选择进行调整.
- 配体支持相互作用至关重要,它们相互影响.
- 直接观察揭示了支持集群催化机制.
相关概念视频
05:12Murine Nasal Lavage Fluid Collection without Blood Contamination
1.7K
The present protocol describes a novel method for avoiding blood contamination in murine nasal lavage fluid (NLF). Since this method ensures the NLF collection without blood contamination, it allows for more accurate detections of immunological components and various respiratory...
1.7K
03:40Nasolacrimal Lavage as a Treatment for Ocular Surface Toxic Soup Syndrome
1.1K
OSTSS leads to pooled inflammatory mediators in the tear film, causing symptoms like epiphora and discomfort. Here, we present a case where therapeutic nasolacrimal lavage every 2 months resolved epiphora and itchiness, suggesting its efficacy as a therapeutic intervention for OSTSS. Additionally, we report subjective improvements in symptoms in 3 additional...
1.1K
04:35Saline Lavage for Sampling of the Canine Nasal Immune Microenvironment
880
Saline nasal lavage can be used to sample the canine nasal immune microenvironment. Because the approach is relatively non-invasive and does not disrupt the nasal tissues, it can be performed serially. Cells and proteins collected from the nasal lavage technique can be processed for various laboratory analyses.
880
08:47Symptom Assessment of Patients with Allergic Rhinitis Using an Allergen Exposure Chamber
2.9K
A protocol for conducting a challenge in an allergen exposure chamber (AEC) facility is presented. AECs have proven to be safe and effective tools for the induction of allergic symptoms or as an endpoint in the efficacy testing of allergen immunotherapy due to their ability to maintain stable particle concentrations and environmental...
2.9K
06:49Reduced Itraconazole Concentration and Durations Are Successful in Treating Batrachochytrium dendrobatidis Infection in Amphibians
12.0K
Batrachochytrium dendrobatidis infection in amphibians can be eliminated using a reduced concentration (0.0025%) and shorter duration (five minute baths for six days) of itraconazole than is generally used. Less mortality and fewer negative side effects were observed using this modified treatment...
12.0K
07:15Intranasal Administration of CNS Therapeutics to Awake Mice
61.4K
A method to intranasally administer drugs to awake mice for the purpose of targeting the brain is described. This method allows for repeat dosing over long periods using intranasal administration of drug without anesthesia, and nose-to-brain delivery with minimal systemic...
61.4K