NSF-DFG MISSION: Unraveling Structures and Dynamics of Plasmonic Catalysts by In Situ X-ray and Electron-Based Probing (CAPTURE)

Energy generation and storage, environmental remediation, and chemical manufacturing require materials that speed up important chemical reactions such as carbon fixation. Often these materials operate in complex, dynamic environments where their structures change. For designing robust high-performance catalysts that reduce energy consumption and waste, it is important to know the atomic-level structure of the catalyst under operating conditions so as to understand why a specific material catalyzes an important chemical reaction or why performance deteriorates under certain conditions. Principal Investigator Jain from University of Illinois at Urbana-Champaign and his collaborators from Humboldt University and Helmholtz-Zentrum in Berlin are using advanced characterization methods to image in real time the atomic structures of catalysts comprised of light-absorbing nanoparticles of metals that catalyze carbon fixation using light energy. Their research will lead to more robust catalysts for solar-powered carbon fixation and sustainable chemical manufacturing technologies. In the practice of heterogeneous catalysis, the surface structure, composition and/or oxidation state of the catalyst may change into the active form in response to operating conditions. Therefore, there is a need to probe the chemical state of catalysts in situ under the action of stimuli and reactive conditions. As one prime example, plasmonic nanostructures are known to exhibit superlative catalytic activity under light; however, such nanostructures can dynamically evolve in operando due to effects of plasmonic excitation, heat, and reactive environments. Principal Investigator Jain and collaborators will elucidate currently unknown active-state structures and dynamics of plasmonic nanocatalysts using a laser-coupled dynamic environmental transmission electron microscopy at UIUC complemented by high-resolution electron energy loss spectroscopy and in-situ X-ray absorption spectroscopy in Berlin. The team will probe hybrid nanostructures consisting of plasmonic absorbers with catalytic domains during plasmon-catalyzed carbon dioxide and carbon monoxide hydrogenation. The aim is to uncover the structures of the active states of these hybrid nanostructures and elucidate dynamic structural fluctuations that may underlie their catalytic activities. These insights will fill the current knowledge gap in structure–reactivity relationships for hybrid plasmonic catalysts. The success of this project may lead to design principles and protocols for more robust photocatalysts for solar-powered carbon dioxide reduction and sustainable synthesis of fuels and chemicals from carbon dioxide. The work may also advance the use of advanced electron microscopy methods in the chemical industry for examination of nanoparticle-based catalysts and train students for the research and development workforce. 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.