将n-pentane异构活性与WO(x) /ZrO2的表面密度相关
Nikolaos Soultanidis1, Wu Zhou, Antonis C Psarras
1Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, USA.
支持的氧化催化剂在使用无形前体时表现出最佳的n-pentane异构化活性. 较高的化温度通过形成活性Zr-WO(x) 集群来提高催化性能.
科学领域:
- 催化剂是一种催化剂.
- 材料科学 材料科学 材料科学
- 表面化学 表面化学
背景情况:
- 硫黄氧化物在上 (WO(x) /ZrO(2)) 是一个关键的酸催化剂模型.
- 它在烯异构和酒精脱水中的活性显示了火山形状对表面密度的依赖.
- 然而,它在更苛刻的反应中的表现,如n-pentane异构化,尚未在表面密度方面进行探索.
研究的目的:
- 研究n-pentane异构活性和WO(x) /ZrO(2) 的选择性.
- 确定表面密度,支前体类型和化温度对催化剂性能的影响.
- 了解结构变化及其与催化行为的相关性.
主要方法:
- 使用无形ZrO (x) (OH) (4-2x) 和晶体ZrO (x) (2) 前体合成WO (x) /ZrO (x).
- 对n-pentane异构化活性和选择性的评估.
- 分析的表面密度,支类型和化温度的影响.
- 使用偏差校正的高分辨率扫描传输电子显微镜 (STEM) 和胺吸附红外光谱学进行了表征.
主要成果:
- 无形ZrO (x) (OH) (4-2x) 支产生了WO (x) / ZrO (2) (WZrOH),其峰值活性在5.2W·nm (-2).
- 水晶ZrO(2) 的支持导致了几乎不活跃的催化剂 (WZrO(2)).
- 在773-973K的化使催化活性增加了多达两倍,与通过STEM观察到的0.8-1nm Zr-WO (x) 集群的形成相关.
- 布伦斯特酸度保持不变,而易斯酸度随着化温度的增加而下降.
- 催化剂活动在前2小时内达到峰值,这表明Zr-WO(x) 集群的激活过程.
结论:
- 选择的基支前体显著影响WO(x) /ZrO(2) 催化性能为n-pentane异构化.
- 无形石的前体在实现高活性方面优越.
- 优化的化条件促进了活性Zr-WO(x) 集群的形成,提高了催化效率.
- 观察到的失活或激活行为需要进一步调查活跃站点的动态性质.
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