Unconventional Noble Metal Nanoparticles with Enhanced Catalytic Properties: A Combined Experimental and Theoretical Study

具有增强催化性能的非常规贵金属纳米颗粒：实验与理论相结合的研究

• 批准号: 1505135
• 负责人: Simon Humphrey
• 金额: $ 39.11万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1505135&HistoricalAwards=false
• 关键词: Unconventional; Noble; Metal; Nanoparticles; Enhanced

With support from the Macromolecular, Supramolecular and Nanochemistry program in the Division of Chemistry, the goal of this project is to prepare new metal nanoparticle catalysts for energy and environmental applications. Many large-scale catalytic processes are responsible for the formation of fuels, polymers and textiles, drugs and food additives, and are used in the remediation of toxins and environmental pollutants, and many of these require precious metal catalysts. Precious metals are both scarce and expensive. It is, therefore, of critical importance to find ways to prepare catalysts that require less precious metal, whilst maintaining the catalytic performance and also reducing the amount of waste by-products that are formed. Metal nanoparticles are discrete entities consisting of just a few hundred to a few thousand atoms. They might appear to be small fragments or as pieces "cut-away" from bulk metals. However, they are known to have properties that are superior to bulk metal, including enhanced catalytic behavior. For important chemical reactions that occur on metal surfaces, precious metal nanoparticles are very attractive because they have very large surface areas compared to their volumes, resulting in improved efficiency. In this project, the research groups of Dr. Simon Humphrey and Dr. Graeme Henkelman at the University of Texas at Austin are combining their expertise to prepare precious metal nanoparticles with previously unstudied structures, and to explain how the structures result in improved catalytic properties. A major goal of this research activity is to prepare nanoparticles based on mixtures of metals (alloys) that permits the dilution of very expensive metals with cheaper and more available metals, while also achieving improved catalytic properties. Another goal is to use microwave heating as a cheaper and faster way to prepare the nanoparticles. This project also incorporates important educational goals that are aimed at inspiring undergraduate students to actively participate in aspects of the research. A new microwave materials synthesis Freshman Research Initiative (FRI) stream is being introduced at the University of Texas - Austin, which enables undergraduates to engage in laboratory-based research, and promotes a deeper appreciation for scientific research. This is a collaborative project between a materials synthesis and catalysis group (Simon Humphrey) and a theoretical modeling group (Graeme Henkelman) at the University of Texas at Austin. The major objectives of this research activity are to synthesize metal nanoparticles (MNPs) with defined compositions, to test the MNPs in model catalytic reactions relating to industrially-relevant large-scale chemical transformations, and to use detailed and state-of-the-art theoretical approaches to gain a deep understanding of the relationships between surface reactivity and MNP structure. Experiment and theory are combined to elucidate general trends in reactivity as a direct function of composition; this ultimately provides important information that can be applied to direct the synthesis of other new MNPs with desired reactivity. The project features the preparation of a variety of novel metal nanoparticles (MNPs) using an innovative and technologically-relevant microwave-assisted method. Compared to classical methods, microwave-assisted synthesis allows for faster reaction times, easier scale-up, and can also allow access to products that cannot otherwise be obtained. Microwave heating is becoming popular in organic chemistry and the biosciences, but it has still yet to be fully exploited in materials and inorganic chemistry. In this project, microwave synthesis is exploited to gain access to MNPs with defined size and surface structure, and with unusual hybrid core-shell and alloy compositions. The surface chemistry of these previously unstudied MNPs are explored through model reaction studies including vapor- and liquid-phase reactions including hydrocarbon hydrogenation, carbonylation, and NOx reduction. Another goal of this project is the development of new theoretical approaches that can provide a more accurate description of surface reactivity than is presently available. This project also incorporates important educational goals that are aimed at inspiring undergraduate students to actively participate in aspects of the research. A new microwave materials synthesis Freshman Research Initiative (FRI) stream is being introduced at the University of Texas - Austin, which enables undergraduates to engage in laboratory-based research, and promotes a deeper appreciation for scientific research.

在化学系高分子、超分子和纳米化学项目的支持下，该项目的目标是制备用于能源和环境应用的新型金属纳米颗粒催化剂。 许多大规模催化过程负责形成燃料、聚合物和纺织品、药物和食品添加剂，并用于修复毒素和环境污染物，其中许多需要贵金属催化剂。 贵金属既稀缺又昂贵。 因此，找到制备需要较少贵金属的催化剂的方法至关重要，同时保持催化性能并减少形成的废副产物的量。 金属纳米颗粒是由几百到几千个原子组成的离散实体。 它们可能看起来是小碎片，或者是从大块金属上“切下来”的碎片。 然而，众所周知，它们具有优于块体金属的性能，包括增强的催化性能。 对于金属表面发生的重要化学反应，贵金属纳米粒子非常有吸引力，因为与体积相比，它们具有非常大的表面积，从而提高了效率。 在该项目中，德克萨斯大学奥斯汀分校的 Simon Humphrey 博士和 Graeme Henkelman 博士的研究小组将他们的专业知识结合起来，制备具有以前未研究过的结构的贵金属纳米粒子，并解释这些结构如何提高催化性能。 这项研究活动的主要目标是制备基于金属（合金）混合物的纳米颗粒，该纳米颗粒允许用更便宜和更容易获得的金属稀释非常昂贵的金属，同时还实现改进的催化性能。 另一个目标是使用微波加热作为制备纳米颗粒的更便宜和更快的方法。 该项目还包含重要的教育目标，旨在激励本科生积极参与研究的各个方面。 德克萨斯大学奥斯汀分校正在推出一种新的微波材料合成新生研究计划（FRI），该计划使本科生能够参与基于实验室的研究，并促进对科学研究的更深层次的认识。 这是德克萨斯大学奥斯汀分校材料合成和催化小组（Simon Humphrey）和理论建模小组（Graeme Henkelman）之间的合作项目。 这项研究活动的主要目标是合成具有确定成分的金属纳米颗粒（MNP），在与工业相关的大规模化学转化相关的模型催化反应中测试 MNP，并使用详细和最先进的技术理论方法来深入了解表面反应性与 MNP 结构之间的关系。 实验和理论相结合，阐明反应性的总体趋势作为组成的直接函数；这最终提供了重要的信息，可用于指导合成具有所需反应性的其他新型 MNP。 该项目的特点是使用创新且技术相关的微波辅助方法制备各种新型金属纳米颗粒（MNP）。 与经典方法相比，微波辅助合成可以实现更快的反应时间、更容易的放大，并且还可以获得通过其他方式无法获得的产品。 微波加热在有机化学和生物科学中越来越流行，但在材料和无机化学中尚未得到充分利用。 在该项目中，利用微波合成来获得具有特定尺寸和表面结构以及不寻常的混合核壳和合金成分的 MNP。 通过模型反应研究探索了这些以前未研究过的 MNP 的表面化学，包括气相和液相反应，包括烃加氢、羰基化和氮氧化物还原。 该项目的另一个目标是开发新的理论方法，可以提供比目前可用的更准确的表面反应性描述。该项目还包含重要的教育目标，旨在激励本科生积极参与研究的各个方面。 德克萨斯大学奥斯汀分校正在推出一种新的微波材料合成新生研究计划（FRI），该计划使本科生能够参与基于实验室的研究，并促进对科学研究的更深层次的认识。