The Teixeira Research Group has a diverse set of research interests, primarily focused on utilizing the fundamentals of reaction engineering to understand heat, mass and kinetic limitations in complex systems. These approaches are being applied to the fields of Catalysis, Materials Science, Energy and Pharmaceuticals.
Prospective catalyst design requires understanding of reaction fundamentals (thermodynamics, kinetics, and transport). By layering reaction theory, catalytic reactions can be driven to non-thermodynamically preferred products by introducing kinetic/transport limitations. Utilizing microfluidic devices, microcrystallization becomes possible for single crystals mechanistic studies to better understand the complex and dynamic nucleation, templating and growth mechanisms involved in zeolite, MOF and organic crtstal growth. Classical surface science models consider activated reactions that can often be limited by strong or weak surface coverages. By applying modern reaction engineering techniques, operating outside of this classical thermodynamically-limmited domain may enable a new pathway for synthetic fuels and chemicals. At high heat flux and temperatures (T > 500 C), woody biomass decomposes into a liquid melt that exhibits interesting fluid mechanics, kinetics and heat transfer phenomena. Here, an aerosol droplet was simulated and experimentally validated to describe the mechanims for non-volatile species entrainment in bio-oils. Zeolites are microporous materials with a network of interconnected pores. By understanding the growth mechanism and examining surface characteristics and transport limitations, we gain insight into understanding the materials and informing the next generation syntheses.
Current Research Focus:
1. Zeolite Crystallization
Zeolites are amazing materials that exhibit well-defined crystallinity and pore networks that are made up primarily of Al, Si and O. By using various templating agents, hundreds of stable (and metastable) crystal structures have been synthesized. However, to successfully grow a desired crystal, it is often equal parts science and art. This typically requires a seasoned chemist and substantial trial before succeeding. The goal of this research thrust is to demystify this art by deconvoluting the complex transport, thermodynamic and kinetic phenomena involved during zeolite crystallization. This is done with a combination of microfluidic platforms, in situ analytics and kinetic modeling.
2. Non-Isothermal Catalytic Surface Chemistry
Classical heterogeneous catalysis focuses on understanding the thermodynamics of surface binding to offer retrospective and prospective insight into catalytic activity. This research thrust considers the dynamics of reacting systems and utilizes microfluidic and transport design elements to examine dynamic, non-isothermal catalysis for realizing new synthetic pathways. Applications include diatomic nitrogen or methane activation chemistries.
3. Continuous Flow Processing for Pharmaceuticals and Clean Water
Applying fundamental principles from heat transfer, mass transfer and kinetics to classical batch processing has enabled new pathways for green production of pharmaceuticals (flow chemistry) and clean water. Specific interests focus on transport limitations during solid phase peptide synthesis (hierarchical materials), and tubular flow micro-reactors for water purification.
4. Catalytic Hydrothermal Liquefaction (HTL) of Municiple Waste to Energy
Classical thermal processing technologies (pyrolysis, combustion, torrefaction, etc.) require small, dry feedstocks. HTL takes a wet slurry, and catalytically depolymerizes complex mixtures of carbohydrates, proteins and fats (food waste) into an upgradable, renewable oil. Along with the Timko group, HTL is an exciting, active part of the Teixeira Lab.
5. Electrochemical Energy Systems for Storage and Generation
Our energy infrastructure is being shaken up by the presence of distributed energy generation from renewables. This, in tern, requires creative methods for storing and withdrawing electricity on demand. In this work, we explore methods for direct ammonia solid oxide fuel cells and liquid gallium batteries for potential solutions to this challenging problem.
Former research has focused on:
6. Biomass Fast Pyrolysis
Working with the Dauenhauer Group (UMN) to ellucidate the mysteries of biomass thermal decomposition (pyrolysis). This work included the discovery of the molten liquid aerosol ejection mechanism for entraining non-volatile organics and inorganics. Studies included fluid mechanics, mass transfer and heat transfer.
7. Diffusion Limitations in Zeolites and SPPS
Microporous and hierarchical zeolites and polymeric systems are extremely attractive for their extreme surface areas and potential for catalytic activity and solid phase synthesis. However, complex noncrystalline transport limitations present themselves not only in the bulk of a particle (configurational diffusion), but also at the surface. Understanding the barriers that exist at the surface of zeolites, and moreover what us the physical structure of the surface remains a major research challenge.