Collaborative Research: Predicting Support-Wetting and Electronic Structure to Enable the Rational Synthesis of Metal-Cluster Catalysts with Controlled Reactivity

Professor Linxiao Chen at the University of North Texas (UNT) and Professors Jean-Sabin McEwen, Simone Raugei, and Colin Lehman-Chong at Washington State University (WSU) are studying the shape of extremely small metal clusters on a catalyst surface. Small clusters are often more efficient than larger particles in advanced chemical manufacturing. Their performance is strongly influenced by their shape and electronic structure, which are not well understood. The team aims to predict these two factors using simple, easily accessible parameters. This understanding will guide the synthesis of flattened clusters to enhance their efficiency in a broad range of important chemical reactions, reducing the cost of chemical production across sectors including fuels, polymers, and fine chemicals. Such outcomes will enhance the economic competitiveness of advanced chemical manufacturing in the United States. The UNT team will synthesize, characterize, and test the catalytic performance of these clusters, while the WSU team will carry out theoretical calculations to complement experimental results. Educationally, this collaborative effort will support and train students at UNT and WSU across multiple levels, providing interdisciplinary research experience through regular collaboration and student exchange. Outreach activities, including the use of interactive printouts generated from computational models and hands-on LEGO-style tools, will promote public dissemination of these findings and spark interest in STEM disciplines. Professor Linxiao Chen at the University of North Texas (UNT) and Professors Jean-Sabin McEwen, Simone Raugei, and Colin Lehman-Chong at Washington State University (WSU) will establish a descriptor-based predictive framework for 1) the support-wetting tendency (shape) and 2) the electronic structure of sub-nanometer supported metal clusters. The UNT team will combine low-energy ion scattering, high-energy-resolution fluorescence detection X-ray absorption spectroscopy, resonant inelastic X-ray scattering, and X-ray photoemission spectroscopy to characterize cluster properties and correlate them with the kinetics of model catalytic reactions. The WSU team will focus on density functional theory calculations coupled with first-principles spectral simulations and a predictive Concerted Coupling Model to establish and predict wetting trends from the electronic structure. The central hypothesis is that the shape and electronic state, and thus catalytic reactivity, of supported sub-nanometer metal clusters are governed by a small set of thermodynamic descriptors, namely the formation enthalpy of the most stable oxide, work function, and electronegativity, which can be systematically modulated by the properties of the metal, support, and adsorbates. This project will enable the rational, data-guided synthesis of well-dispersed catalysts with tunable activity and selectivity, addressing a long-standing challenge in heterogeneous catalysis and enabling validation in representative catalytic reactions. 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.