(6bo) Catalysts for Sustainable Processes: Understanding and Controlling Active Site Environments

Producing chemicals and power without affecting the environment will be increasingly important throughout my career. As population and prosperity continue to increase, the environmental impact of greenhouse gas emission, resource extraction, and chemical processing will need to be mitigated. Doing so in economically viable ways will require: (1) natural gas conversion without emitting CO₂, (2) sequestration of carbon dioxide into chemicals and materials, and (3) novel processes that take advantage of process intensification. My research program will address each of these challenges.

Overall Goal: Understand and develop catalysts and processes to produce chemicals, power, and materials in environmentally sustainable ways

The focus of my future research will be to develop high performance heterogeneous catalysts that enable processes for the economic production of chemicals, fuels, and power without producing carbon dioxide. For example, producing solid carbon instead of CO₂ allows for sequestration of the carbon as a useful material, but requires new catalysts (liquid catalysts) to prevent carbon deactivation. Halogens and other indirect oxidants (gaseous catalysts) may also be used as alternatives to oxygen – which produces CO₂ - in hydrocarbon dehydrogenation reactions. My specific aims are: (a) understand mechanisms in liquid heterogeneous catalytic processes, (b) develop new catalysts and processes in which CO₂ is consumed or never produced and (c) model, demonstrate, and analyze new catalytic systems to imagine economically feasible paths to sustainably produce chemicals, materials, and power.

Scientific Goal: Understand the reaction pathways on the interfaces of gas-liquid and gas-solid catalysts and control the reaction environment of active sites to achieve high performance

The first three projects I intend to work on will be: (i) Understanding catalytic melts for the conversion of methane to separable carbon and hydrogen. This will evolve to include the CO₂ reforming of methane and other reactions producing solid carbon. (ii) Investigating how catalytic environments affect performance in soft-oxidant (halogens, sulfur, etc.) mediated reactions. This will include molten salt environments for CO₂-free alkane conversion and hydrogen halide reactions, as well as the confined environment of zeolites for methyl halide reactions. (iii) Application of (i) and (ii) to chemical looping reactions for integrated chemical conversion and product separation. Over time, these will evolve to include additional reactions and catalytic systems that provide a set of sustainable methods to produce commodity chemicals, fuels, and electrical power from hydrocarbons and carbon dioxide.

PhD Research:

During my PhD with Professors Eric McFarland and Horia Metiu at the University of California, Santa Barbara, I worked on molten metal catalysts^1,2 and molten salt catalysts^3,4 for methane pyrolysis and alkane dehydrogenation. The molten metal catalysts were used in bubble column environments to allow for continuous carbon separation in methane pyrolysis. The molten salt catalyst was used to maintain a neutralizing reaction environment proximate to gas-phase halogen reactions to prevent undesirable hydrogen halide addition. The two catalyst types were used for dehydrogenation reactions to create CO₂-free chemical and power production from natural gas. In collaborations with theorists, we were able to create descriptors for catalytic activity for methane pyrolysis (calculated Bader charge), and model a complete microkinetic pathway for alkane halogenation with mixtures of iodine and bromine. We also completed technoeconomic analyses of methane pyrolysis to assess the impact of different research areas, which lead to focusing on the reaction selectivity.

Postdoctoral Research:

In my work at Stanford University, the confined environment of 8 membered ring pores in mordenite are being used to selectively prevent the formation of intermediates leading to undesirable hydrocarbon formation in the carbonylation of methanol to acetic acid. Modifications of mordenite have resulted in improved selectivity through targeted site passivation. The reaction is part of a novel syngas-to-ethanol process.

Other research:

In addition to the projects mentioned above, I have worked on the conversion of CO₂ to fuels in industry⁵ and academia⁶. I directed the catalyst development of a CO₂ reforming company for several years. This included approximately $1,000,000 in lab and benchtop scale testing and IP development.

Teaching Interests:

I look forward to the opportunity to mentor students of all backgrounds as they make choices that will benefit them, those around them, and our society as a whole. I intend to teach each of the core chemical engineering courses eventually, and my research background gives me the ability to teach all levels of kinetics, reaction engineering, physical chemistry, and data analysis courses. My TAing background gives me confidence in teaching chemistry and chemical engineering laboratory courses. My work as a process engineer and chemical engineer gives me the knowledge to teach Separations, Process Design, Chemical Processing, and Material and Energy Balances. Additionally, I would like to develop a course in catalysis.

References

1. D. Chester Upham, Alexander Khechfe, Vishal Agarwal, Zachary Snodgrass, Michael Gordon, Horia Metiu, and Eric W. McFarland. Catalytic molten metals for the direct conversion of methane to hydrogen and separable carbon. Science, 2017 358 (6365) 917-921

2. Brett Parkinson, Mojgan Zavareh, D. Chester Upham, Benjamin Ballinger, Simon Smart, and Eric W. McFarland. Hydrogen production using methane: techno-economics of decarbonizing fuels and chemicals. International Journal of Hydrogen Energy, 2018 43 (5) 2540-2555

3. D. Chester Upham, Zachary R. Snodgrass, Mojgan Zavareh, Thomas McConnaughy, Michael Gordon, Horia Metiu, and Eric W. McFarland. Molten salt chemical looping for reactive separation of HBr in a halogen-based natural gas conversion process. Chemical Engineering Sciences, 2017 160 245-253

4. D. Chester Upham, Michael Gordon, Horia Metiu, and Eric W. McFarland. Halogen mediated oxidative dehydrogenation of propane using iodine or molten lithium iodide. Catalysis Letters, 2016 146 744-754

5. D. Chester Upham, Howard Lam-Ho Fong. Combined steam reforming and dry reforming of hydrocarbons to produce synthesis gas. Carbon Sciences, Inc. Application number 18832.7.1. US 61/678,498 2013

6. D. Chester Upham, Alan R. Derk, Sudanshu Sharma, Horia Metiu, and Eric W. McFarland. CO2 methanation by Ru-doped ceria: the role of the oxidation state of the surface. Catalysis Science & Technology, 2015 5 (3) 1783-1791