A Non-equilibrium Flame Aerosol Process to Create High-entropy Nanomaterials
Abstract
High-entropy nanomaterials, incorporating five or more elements in a single phase, provide vast compositional diversity and fascinating characteristics such as lattice distortion, synergistic interactions among multiple elements, and altered kinetics of phase change. However, elemental immiscibility and crystal complexity have limited development of a general synthesis strategy for them. In this talk, I will describe a one-step, continuous, and scalable flame aerosol technique for synthesizing metastable and high-entropy nanomaterials. The far-from-equilibrium reaction kinetics, with material formation in milliseconds followed by rapid quenching, circumvents limitations of elemental immiscibility to enable production of both stable and metastable nanomaterials with an unprecedented diversity of compositions. The materials we have synthesized by this route span a broad spectrum of inorganic materials, including a metastable ceramic solid solutions, high-entropy nano-ceramics, supported high-entropy alloy nanoparticles, kinetically stabilized MOFs, and high-entropy MOFs. Meanwhile, it enables mixing of multiple elements, including transition metals, alkaline metals, lanthanides, noble metals, and p-block metals from the different regions of the periodic table, into a single-phase ceramic, alloy, or MOF. This provides a near-infinite compositional space for material design and optimization. The physical and chemical properties of materials, such as element type and ratio, crystal structure, particle size, specific surface area, and defect density, can be altered to meet a wide range of application needs. The produced metastable and high-entropy nanomaterials show excellent performance in energy, environment, and electronic applications including catalysis, electrochemistry, and gas sensing. Applications demonstrated to date include methane reforming, CO2 hydrogenation to CO or methanol, CO lean combustion, fuel cell catalysis, water electrolysis, H2 detection, and thermal insulation.
Bio
Mark Swihart is a SUNY Distinguished Professor of Chemical and Biological Engineering and Empire Innovation Professor in the RENEW Institute at the University at Buffalo (SUNY). He earned his B.S. from Rice University in 1992 and Ph.D. from the University of Minnesota in 1997, both in chemical engineering. After one year of post-doctoral research in mechanical engineering at the University of Minnesota, he joined the Department of Chemical and Biological Engineering at the University at Buffalo in 1998. His research interests center on the synthesis, processing, and applications of inorganic nanomaterials. He is a fellow of the American Association for the Advancement of Science and the American Institute of Chemical Engineers and has received awards from the American Chemical Society, American Institute of Chemical Engineers, American Association for Aerosol Research, and the Electrochemical Society.