Center: CCI Phase I: NSF Center for Multimodal Observations for Single Atom Imaging of Chemistry (MOSAIC)

University Of Chicago, Chicago IL

Investigators

Abstract

The NSF Center for Multimodal Observations for Single Atom Imaging of Chemistry (MOSAIC) is supported by the Centers for Chemical Innovation (CCI) Program of the Division of Chemistry. The ability to visualize chemical reactions at the single-atom level and in real time would be truly transformative to the field of chemistry. Scientific achievements in this area would allow scientists to understand reaction mechanisms and the relationships between molecular structures and their properties at previously inaccessible resolutions. MOSAIC will achieve these goals via 1) the nanofabrication of novel liquid cells with enhanced functionality and 2) the coupling of these liquid cells with electron microscopy to reveal new insights into chemical reactions at a range of scales, from atoms to clusters to 2D materials. Activities within this center will include collaboration with a wide range of companies to commercialize the MOSAIC platforms and rotations for mentees between different institutions to broaden scientific expertise. The center will utilize various programs to recruit and support underrepresented students. Public science communication and outreach will be enhanced through programs such as the “South Side Science Festival” and collaboration with some of the largest science museums in the country, as well as the creation of educational multimedia materials in collaboration with school districts and public libraries. MOSAIC’s real-time, single-atom level visualization will elucidate (i) reaction mechanisms at the finest level, such as the atomic or molecular configuration of intermediates, the pathways by which intermediates are converted into products, and rate-limiting steps in those pathways, and (ii) how properties change with the instantaneous atomistic structures during reactions or in response to external stimuli. Achieving breakthroughs in the visualization of chemical reactions at the single-atom level and in real time will depend upon the development of specialized liquid cell platforms with enhanced capabilities in scanning/transmission electron microscopy (S/TEM). MOSAIC will employ nanofabrication to permit the spatial control of liquid cell compartments, the thickness of the liquid, and the geometry of viewing windows, thereby allowing quantitative and high-resolution analysis of chemical reactions. MOSAIC will utilize these novel liquid cell platforms in a highly integrated research program that focuses on single-atom catalysis, cluster chemistry, nanocrystal synthetic chemistry, and surface coatings on 2D membranes using organic molecules with surface-specific reactivities. Liquid cell platforms will also be integrated with cutting-edge capabilities in S/TEM, such as atomic-resolution vibrational electron energy-loss spectroscopy (EELS) with chemical sensitivity to visualize bonds and valence states of elements, 4D-STEM to map structures and chemical bonding, and electron tomography for 3D structures. The data analysis approach and chemical interpretations will benefit from theory-guided information extraction using artificial intelligence/machine learning (AI/ML) and density functional theory modeling. 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.