Tunable Control of Bimetal Alloys from Geo-Inspired Perovskite Oxides

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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.