Probing the Structure-property Relationship of Core/Shell Bimetal Nanoparticles as a Model Catalyst

探讨核/壳双金属纳米颗粒作为模型催化剂的结构-性能关系

• 批准号: 1134535
• 负责人: Michael Wong
• 金额: $ 29.99万
• 依托单位: William Marsh Rice University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2016-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1134535&HistoricalAwards=false
• 关键词: Probing; Structure; property; Relationship; Core

AbstractTechnical ImpactThe combination of two metals to make a bimetallic catalyst frequently leads to a more catalytically active material than either constituent metal. Besides higher activities, bimetallic catalysts can have improved selectivities and greater deactivation resistance. The catalytic chemistry that explains how bimetallic enhancement arises is not well explained. Depending on the chemical reaction, the enhancement can be attributed to a geometric effect, an electronic effect, or a mixed metal site effect. The difficulties in determining the source of catalytic enhancement are numerous: enhancement could be due to a combination of these effects; the bimetallic nanostructure is not well-controlled at the synthesis level; there may be a metal-support interaction; or the studied bimetallic nanostructure can reconfigure during the chemical reaction.So, how to develop a greater understanding of bimetallic catalysts so that they may be exploited appropriately is a significant question. Professor Michael Wong at William Marsh Rice University in Houston has an approach to developing more of this understanding. Wong intends to focus on a model of a bimetallic catalyst in which metallic nanoparticles of one metal are the support for the second active metal. The interaction is built-in and controllable, and amenable to the analysis of the bimetallic nanostructure using spectroscopic methods near reaction conditions; and culminating in the quantification of their catalytic properties under reaction conditions that do not modify the nanostructure. The model system is based on previous studies using palladium metal supported on gold nanoparticles, and the model test reaction is the catalysis in the water phase of trichloroethene hydrodechlorination. Continued innovations in catalysis technology rely on the development of novel materials and the rigorous elucidation of reactivity dependence on catalyst nanostructure.PdAu bimetallic catalysis has shown some promise as a new technology for water-phase hydrodechlorination. This technology is important for pollution control in groundwater, a source for 50% of US drinking water.Broader ImpactThis proposal describes a three-year research and teaching plan consisting of multidisciplinary training of graduate and undergraduate students in materials chemistry, heterogeneous catalysis, chemical engineering fundamentals, and colloid science. Three new educational and community outreach activities are proposed: a yearly NanoDays demonstration at the Children's Museum of Houston, a local-area high school teachers development program in coordination with the NSF-sponsored RET program at Rice, and a lab module design project incorporated into the graduate-level kinetics/reactor engineering course. This award is being funded jointly by the CBET Catalysis and Biocatalysis Program and the CHE Catalysis Program.

技术影响将两种金属组合制成双金属催化剂，通常会产生比任何一种组成金属更具催化活性的材料。双金属催化剂除了具有更高的活性外，还可以具有更高的选择性和更强的抗失活能力。解释双金属增强如何产生的催化化学没有得到很好的解释。根据化学反应的不同，这种增强可以归因于几何效应、电子效应或混合金属位效应。确定催化增强的来源有很多困难：增强可能是由于这些效应的结合；双金属纳米结构在合成水平上没有得到很好的控制；可能存在金属-载体相互作用；或者所研究的双金属纳米结构在化学反应中可以重新配置。因此，如何更好地了解双金属催化剂，以便适当地开发它们是一个重要的问题。休斯敦威廉·马什·赖斯大学的迈克尔·王教授有一种方法可以更好地理解这一点。王打算专注于一种双金属催化剂的模型，其中一种金属的金属纳米颗粒是第二种活性金属的载体。这种相互作用是内置的和可控的，并且可以在反应条件附近使用光谱方法分析双金属纳米结构；最终在不改变纳米结构的反应条件下对其催化性能进行量化。该模型体系是在前人研究的基础上，以金属钯负载金纳米粒子为基础，以三氯乙烯水相催化加氢脱氯反应为模型实验反应。催化技术的不断创新有赖于新材料的开发和催化剂纳米结构对反应活性依赖性的严格阐明。PdAu双金属催化作为一种新的水相加氢脱氯技术显示出了一定的前景。这项技术对控制地下水的污染非常重要，地下水是美国50%的饮用水的来源。该提案描述了一个为期三年的研究和教学计划，包括对材料化学、多相催化、化学工程基础和胶体科学的研究生和本科生进行多学科培训。建议开展三项新的教育和社区外展活动：休斯顿儿童博物馆的年度NanoDays演示；与美国国家科学基金会赞助的莱斯RET计划协调的当地高中教师发展计划；以及纳入研究生一级动力学/反应堆工程课程的实验室模块设计项目。该奖项由CBET催化和生物催化计划和CHE催化计划联合资助。