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.

我们这个时代最大的社会挑战之一是寻求替代燃料资源，以减少我们目前的温室气体排放和对外国原油的依赖。特别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是缓慢和低效的，而醇的化学途径主要是酸催化的过程，产生大量的废物。首席研究员罗伯特·F。来自伊利诺伊大学芝加哥分校的Klie和Randall Meyer认为，如果能够使其成为一种有效的催化过程，那么替代路线是最好的选择。在该提案中，将研究使用非均相纳米催化剂将来自气化木质素（其丰富、便宜且几乎没有竞争应用）的合成气转化为乙醇和其他醇的可行性。关键是利用铑在费托反应中的独特活性来生产铑。PI将集中于发展如何有效地合成乙醇的基本理解可以实现促进铑催化剂。不幸的是，大多数使用未促进的Rh催化剂的CO加氢研究已经证明了对甲烷的强选择性和低的选择性。在醇选择性方面的显著改进是必要的。据PI称，改进这一过程的关键在于解开催化剂促进剂的秘密。 PI相信，通过对负责将合成气高选择性和活性转化为醇的活性位点进行详细研究，可以获得实质性的收益。如果该位点可以明确识别，则可以开发合成方法以适当地靶向其产生，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，在可以从许多常规光谱技术（没有能力定义位置）提取的大量信息与可以从传统显微镜技术（没有能力表征成分和键合）获得的信息之间存在信息差距。为了规避这些限制，PI将联合收割机结合他们在两个不同领域的专业知识，化学工程和凝聚态物理，形成一个跨学科的研究团队。Z衬度成像、电子能量损失谱（EELS）和使用密度泛函理论（DFT）的第一性原理建模的组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）计算将这些与选择性醇形成相关。为了实现这一目标，PI将联合收割机结合他们在两个不同领域的专业知识，化学工程和凝聚态物理，形成一个跨学科的研究团队。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能力。该计划的一个重要特点是通过对学生进行实验和理论材料科学培训，将研究和教育相结合。这将是非常有价值的研究生群体。此外，学校和PI很好地融入了非常强大的少数民族和STEM计划，这是该项目更广泛的教育影响的一个特点。