Heterogeneous catalysis for a more sustainable world
Growth is the natural antagonist to sustainability, though it is the natural tendency of society. The global population and its standards of living are growing faster than they ever have before, requiring us to develop new ways to reduce our consumption of finite resources while addressing growing concerns over environmental degradation.
Catalysis allows for the fuels and chemicals we rely upon every day to be produced more efficiently by offering alternative pathways for chemical transformations. Heterogeneous catalysts are responsible for approximately 80% of industrial catalytic processes, often preferred due to their ease of implementation without costly separations. By better understanding how these materials work, we can design novel catalysts with lower costs, higher catalytic activities, and higher selectivities for a given application. These can also enable new technologies previously found to be too costly for practical implementation.
The Eagan Sustainable Catalysis Laboratory is dedicated to improving the sustainability of our society through fundamental catalysis research with various focuses such as those described below: designing novel nanostructured materials informed by reaction kinetics models, producing high-demand transportation fuels from sustainable feedstocks, and leveraging functionalities naturally present in grown resources to economically synthesize chemicals with improved properties.
Design of nanostructured catalytic materials informed by multiscale models of reaction kinetics
The greatest challenge in improving the selectivity and activity of a catalytic transformation is often developing a functional understanding of the nature of the reactive site where the magic happens. Without this it is difficult to rationally design improved materials and to determine optimal parameter windows for their utilization. As a result, early catalysis work was often considered more “art” than “science.” Advances in characterization techniques, the development of more controlled synthesis methods, and an improved ease of interdisciplinary collaborations have greatly improved our ability to understand how catalytic materials function by better bridging macro-scale observations to nano-scale behaviors.
The materials utilized in the ESCL are produced via controlled synthesis methods which yield uniform sites with knowable structures. This allows for clear conclusions to be drawn between synthesis, structure, and performance, united by reaction kinetics modeling and collaborations with surface scientists and computational chemists. This approach is uniform throughout the ESCL and is key to achieving its more technological goals.
Synthetic fuels from abundant resources
The global demand for transportation fuels is projected to increase by over 20% over the next 20 years (2020-2040) with the majority of the growth anticipated in heavier “middle-distillate” transportation fuels for aviation, marine, and heavy-duty vehicle applications. In order to meet these demands it is prudent that we turn toward alternative feedstocks to improve sustainability, mitigate environmental degradation, and decrease dependence on foreign entities.
Ideal feedstocks can either be 1) produced efficiently on purpose or 2) obtained as natural byproducts of the global economy. Fitting firmly into the former category are sources such as lignocellulosic biomass. Biomass offers carbonaceous polymers comprising C5 or C6 sugars in the hemicellulose and cellulose fractions as well as complex polyphenolic units in the lignin fraction. Proper combinations of depolymerization, hydrodeoxygenation, and oligomerization chemistries enable the conversion of these species to hydrocarbons in the C8-C22 range for use in middle-distillate fuels. Manipulating the presence and functionality of oxygen in these species may also lead to new and improved fuels, such as ethers with improved combustion properties for diesel engines. In the latter feedstock category are waste materials such as COx and municipal solid waste (MSW). Technologies such as Fischer-Tropsch synthesis have been applied to utilize the former, though sustainability issues have urged the development of alternative technologies to produce long carbon chains from C1 species. MSW serves as a carbon source as well, often first converted to light gas mixtures through gasification prior to C-C coupling for liquid fuel synthesis.
The ESCL is interested in developing and understanding novel technologies to enable sustainable middle-distillate fuel synthesis. Previous focuses are highlighted most clearly in Eagan, N. M. et al., Nature Reviews Chemistry 2019, 3 (4), 223-249.
Commodity and specialty chemicals from highly-functionalized feedstocks
While one of the main arguments for the use of biomass as a fuel precursor is its high carbon content, one of the main arguments against its use is its high oxygen content. Though deoxygenation strategies show promise for this application, the oxygen native to biomass can also be leveraged to produce chemicals with high degrees of functionality. Conventional synthetic routes to produce oxygenated molecules often start with fossil-derived hydrocarbons and face an energetically uphill battle when forcing oxygen in. Biomass, on the other hand, comes from the opposite direction and may therefore enable more efficient synthesis routes. In addition to providing more economical and sustainable paths to conventional chemicals, this can open the door to the production of chemicals with improved properties which are otherwise prohibitively expensive to produce. A broader-reaching approach is to selectively produce “platform molecules” from biomass which serve as jumping-off points for the synthesis of a wide range of new chemicals. This expands the potential of the chemical industry which was originally founded on a narrower set of light alkenes and aromatics. These approaches can enable the sustainable and economical production of a wide variety of chemicals including plastic monomers, solvents, lubricants, additives, and more.
The ESCL is interested in enabling the selective production of conventional and value-added chemicals using sustainable biomass and waste resources as inputs. This involves understanding how the feedstock itself is deconstructed as well as how the resulting small molecules are catalytically transformed. The ESCL uses a logical and holistic approach informed by fundamental catalytic investigations.
