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

该奖项由化学系的化学催化计划资助。三一大学的Bert D.Chandler教授和Christopher J.Pursell教授研究了将廉价金属与金(Au)结合形成双金属纳米粒子催化剂的优势。该项目解决了寻找稀缺和昂贵的催化剂的需要，这些催化剂阻碍了大规模的化学生产。加深对双金属纳米粒子及其催化性能的基本了解，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，有可能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，在核心制备量身定制的纳米颗粒，在外部制备金。这包括寻找新的合成方法来从两种金属中组装数百个原子-这是一个具有挑战性的化学合成问题。其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，并测试新催化剂在一些工业重要反应中的性能改进。将研究与教育相结合为本科生提供了研究机会，让他们在这个全国重要的研究领域获得实践经验，并将他们培养成下一代科学家。新的纳米颗粒和催化剂合成技术被用来在氧化铝和二氧化钛上制备双金属纳米颗粒。主要目标是利用溶液纳米粒子合成的最新进展，开发合成具有挑战性的双金属核壳纳米粒子催化剂的新途径。基于动力学的分析技术正被用于评估新的催化剂，包括(I)故意中毒研究以评估活性中心的相对数量，(Ii)米氏分析中毒实验以评估硫醇中毒的影响，以及(Iii)Hammett关系以探测纳米颗粒表面电荷的变化。这些研究使新的催化剂之间的定量比较成为可能，并允许评估异金属对金纳米颗粒化学的影响。此外，这些研究正在解决有关催化活性中心性质的基本问题。本项目还对最近发现的Au/TiO2光催化剂的“宽带红外吸收”现象进行了扩展，并利用该现象表征了H2和CO在催化剂上的吸附强度。这些物理表征研究与详细的动力学研究相结合，使结构-性质-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，这些研究提供了关于如何使用其他过渡金属来调整Au纳米颗粒化学和催化剂的明确信息，(Ii)测试了最近的计算模型，以及(Iii)为Au基催化剂的潜在新应用提供了洞察力。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.