RUI: Preparation and Kinetic Characterization of New Bimetallic Au-M Selective Hydrogenation Catalysts

该奖项由化学学部化学催化项目资助。三一大学的伯特·d·钱德勒教授和克里斯托弗·j·珀塞尔教授得到资助，研究将廉价金属与金（Au）结合形成双金属纳米颗粒催化剂的优势。该项目解决了寻找稀缺和昂贵催化剂替代品的需要，这些催化剂不利于大规模化学生产。提高对双金属纳米颗粒及其催化性能的基本认识，有可能通过提供更便宜的材料和消费品以及减少污染和工业废物，对美国催化工业和国民经济产生积极影响。该项目包括用一种廉价的金属，如铜、镍和铁，在核心和金在外面制备定制的纳米粒子。这包括寻找新的合成方法来组装两种金属的几百个原子——这是一个具有挑战性的化学合成问题。目标是评估合成方法，了解廉价金属如何改变金的催化化学性质，并测试新催化剂在一些重要工业反应中的性能。将研究与教育相结合为本科生提供了研究机会，使他们在这个国家重要的研究领域获得实践经验，并培养他们成为下一代科学家。新的纳米粒子和催化剂合成技术被用于制备氧化铝和二氧化钛上的双金属纳米粒子。主要目标是利用溶液纳米颗粒合成的最新发展，开发合成具有挑战性的双金属核-壳纳米颗粒催化剂的新路线。基于动力学的分析技术正在被用于评估新的催化剂，包括(i)故意中毒研究，以评估活性位点的相对数量；（ii）中毒实验的Michaelis-Menten分析，以评估硫醇中毒的影响；（iii）哈米特关系，以探测纳米颗粒表面电荷的变化。这些研究使催化剂之间能够进行新的定量比较，并允许评估异质金属对金纳米颗粒化学性质的影响。此外，这些研究正在解决有关催化活性位点性质的基本问题。该项目还扩展了最近发现的Au/TiO2催化剂的“宽带红外吸收”，并利用这一现象来表征催化剂对H2和CO的吸附强度。这些物理表征研究，结合详细的动力学研究，使结构-性能-活性关系的发展成为可能，指导研究人员设计下一代催化剂。特别是，这些研究(i)提供了关于如何使用其他过渡金属调整金纳米粒子化学和催化剂的明确信息，（ii）测试了最近的计算模型，（iii）为金基催化剂的潜在新应用提供了见解。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This award is funded by the Chemical Catalysis Program in the Division of Chemistry. Professors Bert D. Chandler and Christopher J. Pursell of Trinity University are supported to investigate the advantages of combining inexpensive metals with gold (Au) to form bimetallic nanoparticle catalysts. The project addresses the need to find alternatives to scarce and expensive catalysts which are prohibitive to large-scale chemical production. Improving the fundamental understanding of bimetallic nanoparticles and their catalytic properties has the potential to positively impact both the U. S. catalysis industry and the national economy by providing cheaper materials and consumer products as well as reducing pollution and industrial waste. The project involves preparing tailored nanoparticles with an inexpensive metal, such as copper, nickel and iron, at the core and Au on the outside. This includes finding new synthetic means to assemble a few hundred atoms from two metals - which is a challenging chemical synthesis problem. The goals are to evaluate synthetic methods, understand how the inexpensive metal alters the catalytic chemistry of gold, and test the new catalysts for improved performance in some industrially important reactions. Integrating the research with education provides research opportunities for undergraduate students, giving them hands on experience in this nationally important area of research and training them to be the next generation of scientists. New nanoparticle and catalyst synthesis techniques are being employed to prepare bimetallic nanoparticles on alumina and titania. The primary goal is to take advantage of recent developments in solution nanoparticle synthesis to develop new routes to synthetically challenging bimetallic core-shell nanoparticle catalysts. Kinetics -based analytical techniques are being used to evaluate the new catalysts including (i) intentional poisoning studies to evaluate relative numbers of active sites, (ii) Michaelis-Menten analysis of poisoning experiments to evaluate the effects of thiol poisoning, and (iii) Hammett relationships to probe changes in nanoparticle surface charge. These studies enable new quantitative comparisons between catalysts and allow for assessing heterometals affect the chemistry of Au nanoparticles. In addition, these studies are addressing fundamental questions regarding the nature of the catalytic active sites. This project also expands on a recent discovery of "broad band IR absorption" for Au/TiO2 catalysts, and uses this phenomenon to characterize the strength of H2 and CO adsorption on the catalysts. These physical characterization studies, combined with detailed kinetics studies, are enabling the development of structure-property-activity relationships that guide researchers in designing the next generation of catalysts. In particular, these studies are (i) providing clear information regarding how Au nanoparticle chemistry and catalysts can be tuned using other transition metals, (ii) testing recent computational models, and (iii) providing insight into potential new applications for Au based catalysts.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.