Tunable Control of Bimetal Alloys from Geo-Inspired Perovskite Oxides

非技术描述：由于两种金属之间的协同作用，双金属纳米粒子在光学、传感和催化等领域显示出巨大的应用前景。然而，定制和控制负载型双金属纳米颗粒的性能的能力仍然是一个存在的挑战。该项目的重点是开发一类过渡金属掺杂的复合氧化物，能够在还原条件下通过结构转变形成双金属纳米颗粒。然而，对这一过程的机制仍缺乏根本性的了解。这些实验工作将被用来理解双金属纳米颗粒的形成与它们的体缺陷化学和反应环境的函数。外联机会包括举办工程创业讲习班，目的是让人数不足的工程专业学生更多地参与。这项工作为化学工程、材料科学和固态化学的本科生和研究生提供了令人兴奋的研究。此外，学生可能会在半导体或能源行业找到工作。技术细节：受地质启发的钙钛矿材料，即那些精选的钙钛矿氧化物家族(LaFeO3，SrTiO3等)，利用金属掺杂剂的离子传输在还原环境中形成纳米颗粒。形成的纳米颗粒具有内在的热稳定性，这些钙钛矿氧化物丰富的缺陷化学可以用来定制双金属合金纳米颗粒的尺寸和组成。该项目包括三项研究，以获得对出溶现象的基本见解：1)阐明控制双金属纳米颗粒出溶的相关参数；2)确定操纵体缺陷化学如何改变纳米颗粒的尺寸和组成；以及3)使用原位光谱和显微研究来了解纳米颗粒的成核和生长机制。研究生和本科生将在国家实验室使用最先进的工具进行培训，例如原位X射线吸收光谱分析。教育努力促进工程转学学生参与研究和创业。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。

NON-TECHNICAL DESCRIPTION: Bimetallic nanoparticles show great promise for various applications ranging from optical, sensing, and catalysis due to synergistic interactions between the two metals. However, the ability to tailor and control the properties of supported bimetallic nanoparticles is still an existing challenge. This project focuses on developing a family of transition metal-doped complex oxides capable of forming bimetallic nanoparticles through structural transformations under exposure to reducing conditions. However, a fundamental understanding of the mechanism of this process is still lacking. The experimental efforts will be used to understand the formation of bimetallic nanoparticles as a function of their bulk defect chemistry and reaction environment. Outreach opportunities include an engineering entrepreneurship workshop geared towards increasing the participation of underrepresented engineering students. This work offers exciting research for undergraduate and graduate students in chemical engineering, material science, and solid-state chemistry. In addition, students will likely find employment in the semiconductor or energy sectors. TECHNICAL DETAILS: Geo-inspired perovskite materials, those within a select family of perovskite oxides (LaFeO3, SrTiO3, etc.), use the ionic transport of metal dopants to form nanoparticles under a reducing environment. The nanoparticles formed are inherently thermally stable, and the rich defect chemistry of these perovskite oxides can be used to tailor the size and composition of bimetallic alloy nanoparticles. The project encompasses three studies to gain fundamental insights into the exsolution phenomena: 1) Elucidate the relevant parameters to control the exsolution of bimetal nanoparticles; 2) Determine how manipulation of the bulk defect chemistry can change the size and composition of nanoparticles; and 3) Use in-situ spectroscopic and microscopic studies to understand the nucleation and growth mechanism of nanoparticles. Graduate and undergraduate students will be trained using state-of-the-art tools such as in-situ x-ray absorption spectroscopy at national laboratories. Educational endeavors promote the participation of engineering transfer students in research and entrepreneurship.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.