Understanding the Active Sites in Selective Alcohol Synthesis with Promoted Rh Catalysts

了解促进 Rh 催化剂选择性醇合成中的活性位点

• 批准号: 1067020
• 负责人: Robert Klie
• 金额: $ 30万
• 依托单位: University of Illinois at Chicago
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1067020&HistoricalAwards=false
• 关键词: Understanding; Active; Sites; Selective; Alcohol

1067020KlieOne of the largest societal challenges of our time is the quest for alternative fuel resources that will reduce our current greenhouse-gas emissions and dependence on foreign crude-oil. Of particular interest has been the production of ethanol from cellulosic biomass as a fossil fuel additive/replacement. However, traditional fermentation routes to alcohols are often slow and inefficient, while chemical routes to alcohols are dominated by acid catalyzed processes which generate significant waste. Principal Investigators Robert F. Klie and Randall Meyer from the University of Illinois at Chicago believe an alternative route is the best choice, if it can be made to be an efficient catalytic process. In this proposal, the viability of converting syngas derived from gasified lignin (which is abundant, cheap, and has few competing applications) to ethanol and other alcohols using heterogeneous nano-catalysts will be studied. The key is to harness the unique activity of rhodium for oxygenate production in the Fischer-Tropsch reaction. The PIs will concentrate on developing a fundamental understanding of how efficient synthesis of ethanol can be achieved on promoted rhodium catalysts. Unfortunately, the majority of CO hydrogenation studies using unpromoted Rh catalysts have demonstrated a strong selectivity for methane with a low oxygenate selectivity. A significant improvement with regard to alcohol selectivity is necessary. According to the PIs, the key for improvement of this process lies in unlocking the secrets of catalyst promoters. The PIs are convinced that substantial gains can be made through a detailed investigation of active sites responsible for highly selective and active conversion of syngas into alcohol. If the site can be unambiguously identified then synthesis methods can be developed to properly target its creation, resulting in the highly active and selective catalyst desired. Characterization methods are key to this. However there is an information gap between the extensive information that can be extracted from the many conventional spectroscopic techniques (without the ability to define the location), and what can be obtained from traditional microscopy techniques (without the ability to characterize composition and bonding). In order to circumvent these limitations, the PIs will combine their expertise in two dissimilar areas, chemical engineering and condensed matter physics to form an interdisciplinary research team. The combination of Z-contrast imaging, electron energy loss spectroscopy (EELS), and first-principles modeling using density-functional theory (DFT) can potentially fill this "information gap. The strengths of this effort lie in the PIs ability to synthesize promoted Rh nano-catalysts, characterize their atomic and electronic structures on the atomic scale and correlate these with the selective alcohol formation using ab initio density functional theory (DFT) calculations. To achieve this goal, the PIs will combine their expertise in two dissimilar areas, chemical engineering and condensed matter physics to form an interdisciplinary research team. This research aims at contributing basic materials science knowledge that will aid the understanding and development of new capabilities for potential next generation nano-catalysts. An important feature of this program is the integration of research and education through the training of students in both experimental and theoretical materials science. This will be of great value to the graduate students in the groups. In addition the school and the PIs are well-integrated into very strong minority and STEM programs which are a feature of the broader educational impacts of this project.

1067020Klie 我们这个时代最大的社会挑战之一是寻求替代燃料资源，以减少我们当前的温室气体排放和对外国原油的依赖。特别令人感兴趣的是从纤维素生物质生产乙醇作为化石燃料添加剂/替代品。然而，传统的醇发酵途径通常缓慢且低效，而醇的化学途径主要是酸催化过程，会产生大量废物。伊利诺伊大学芝加哥分校的首席研究员 Robert F. Klie 和 Randall Meyer 认为，如果可以将其变成高效的催化过程，那么替代路线就是最佳选择。在该提案中，将研究使用非均相纳米催化剂将气化木质素（丰富、廉价且几乎没有竞争应用）衍生的合成气转化为乙醇和其他醇的可行性。关键是利用铑的独特活性在费托反应中产生含氧化合物。 PI 将集中于对如何在促进的铑催化剂上实现乙醇的高效合成有一个基本的了解。不幸的是，大多数使用未促进的 Rh 催化剂进行的 CO 加氢研究已证明对甲烷具有很强的选择性，而含氧化合物的选择性较低。醇选择性方面的显着改进是必要的。 PI表示，改进这一工艺的关键在于解开催化剂促进剂的秘密。 PI 相信，通过对负责高选择性和主动地将合成气转化为酒精的活性位点进行详细研究，可以取得实质性成果。如果可以明确识别该位点，则可以开发合成方法来正确定位其生成，从而产生所需的高活性和选择性催化剂。表征方法是关键。然而，从许多传统光谱技术（无法定义位置）中提取的大量信息与从传统显微镜技术（无法表征成分和键合）中获得的信息之间存在信息差距。为了规避这些限制，PI 将结合化学工程和凝聚态物理这两个不同领域的专业知识，组建一个跨学科研究团队。 Z 对比度成像、电子能量损失光谱 (EELS) 和使用密度泛函理论 (DFT) 的第一原理建模的结合可以潜在地填补这一“信息空白”。这项工作的优势在于 PI 能够合成促进的Rh 纳米催化剂在原子尺度上表征其原子和电子结构，并使用从头算密度泛函理论 (DFT) 计算将其与选择性醇的形成相关联。结合化学工程和凝聚态物理这两个不同领域的专业知识，形成一个跨学科研究团队，这项研究旨在贡献基础材料科学知识，这将有助于理解和开发潜在的下一代纳米催化剂的新功能。该项目的特点是通过对学生进行实验和理论材料科学方面的培训，将研究和教育融为一体。这对于课题组的研究生来说将会有很大的价值。此外，学校和 PI 很好地融入了非常强大的少数族裔和 STEM 项目，这是该项目更广泛的教育影响的一个特点。