Dr. Steven Tait, Indiana University

Host: Dr. Huang

The central theme of materials chemistry is the dependence of function on structure with the challenge to design composition and structure to achieve novel function. In molecular materials, the selection and positioning of specific functional groups will direct packing and stacking, which determine the electronic and chemical properties of molecular thin films and semiconductors. Design of molecular ligands for metal-organic complexation at surfaces can address the long-standing grand challenge of high selectivity in heterogeneous catalysis. Our group is working to develop principles of on-surface molecular self-assembly1 and of metal-organic complexation2 to gain new insight into molecular layers and new chemical activity at metal single-site catalysts.3 This work involves close collaboration with multiple research groups to synergistically combine talent in design, synthesis, sample preparation, characterization, analysis, theory, and computational modeling. Our group uses a range of surface characterization tools to interrogate these systems under well-controlled environments, including scanning probe microscopy, photoelectron spectroscopy, vibrational spectroscopy, and mass spectrometry. We investigate systems under a variety of conditions: solution/solid interface, ultra-high vacuum, and flow reactor conditions at high temperature and high pressure. Here, I will report on recent results in several aspects of this work. We have demonstrated the impact of conformational entropy in impeding self-assembly, but that this can be overcome with appropriate selection of co-solutes. Metal-organic complexes at surfaces can be designed to achieve single-site metal centers in which we can observe redox isomerism, control of metal oxidation state, transmetallation, and chemical spillover to the support. We have transferred this design concept for single-site catalysts to high-surface-area powder oxide supports and shown that these can operate as effective catalysts in solution and under gas flow conditions. Ongoing work will seek to extend understanding of these systems to achieve molecular thin films and single-site catalysts of greater complexity.

Professor Steven Tait is the Herman T. Briscoe Professor of Chemistry, Adjunct Professor of Physics, Chair of the Department of Chemistry, and Associate Director of the Electron Microscopy Center at Indiana University. He obtained a Bachelor of Science degree in Honors Physics and University Honors from Brigham Young University (Utah, U.S.A.) in 2000. He went on to graduate studies at the University of Washington, where his doctoral studies were co-supervised by Prof. Charlie Campbell in Chemistry and Prof. Sam Fain in Physics. During his graduate students, he received a fellowship to conduct research in the labs of Dr. Bruce Kay and Dr. Zdenek Dohnalek at Pacific Northwest National Laboratory in eastern Washington state. His doctoral work explored the desorption kinetics of small alkanes from solid surfaces, methane dissociation on Pd nanoparticles and the growth and sintering kinetics of Pd nanoparticles on aluminum oxide. He completed his PhD in 2005 and moved to Stuttgart, Germany for postdoctoral work with Prof. Dr. Klaus Kern at the Max Planck Institute for Solid State Research. There he studied the self-organization of supramolecular nanometer-scale structures at surfaces, especially systems formed by metal-organic coordination. Those studies were sponsored by fellowship awards from the Alexander von Humboldt Foundation and the Max Planck Society. In 2008, he moved to Indiana University to establish an independent research group in surface chemistry, catalysis, and nanoscience. He teaches courses in general chemistry, physical chemistry, and surface chemistry and was recognized in 2022 with IU’s James P. Holland and Morley Award for Exemplary Teaching and Service. Prof. Tait serves on several regional and national committees, including the executive committee of the American Chemical Society Division of Colloid and Surface Chemistry, the ACS Society Committee on Publications, and the AVS Prairie Chapter Executive Board. He serves on the editorial board for the journal Surface Science and is an editor of Surface Science Reports. Prof. Tait has held visiting appointments at the University of Warwick (International Visiting Fellow, Institute for Advanced Study) and at the University of Science and Technology of China (Visiting Fellow, Chinese Academy of Sciences). Prof. Tait has organized multiple special topics symposia at national ACS meetings.

Prof. Tait's research group applies an interdisciplinary and collaborative approach to advance surface chemistry and catalysis toward novel solutions to global energy challenges. The Tait lab makes use of molecule designs to program specific architectures at surfaces. Metal-ligand complexation methods have been developed to generate novel single-atom catalysts for selective hydrocarbon chemistry. They also examine fundamental aspects of supramolecular self-assembly and materials design. The Tait lab combines detailed surface analysis of model systems in pristine environments with catalytic characterization and rate analysis under high pressure or ambient conditions.