GOALI: Thermo-catalytic Decomposition of Natural Gas Coupled with Regeneration: Nanostructure Connections and Control

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Hydrogen has several present-day uses including fertilizer production, refining, and boosting natural gas combustion for power generation. Presently hydrogen for these uses is generated by steam-methane reforming, an energy intensive process producing considerable carbon dioxide and consuming substantial water. In contrast thermally driven catalytic decomposition of methane can produce clean hydrogen uncontaminated by reforming byproducts. Thermally driven catalytic decomposition produces hydrogen using roughly half the input energy of steam methane reforming. Operating with renewable energy, thermally driven catalytic decomposition could supply hydrogen for power generation and transportation based on hydrogen fuel cells free of carbon dioxide production. Effectively decarbonizing methane by producing solid carbon in addition to clean hydrogen, thermally driven catalytic decomposition can facilitate the transition to the hydrogen economy. This project promotes elementary and high-school engagement in science though summer science camps and after-school demonstrations.Carbon is an ideal catalyst for thermally driven catalytic decomposition given its high temperature stability and resistance to poisoning. Yet its activity declines with reaction time. Surprisingly, deposited carbon nanostructure has not been examined by microscopy nor connected with its initial activity and decline. The project goal is to realize thermally driven catalytic decomposition as a semi-continuous process via coupling thermally driven catalytic decomposition with a regeneration reaction for the carbon serving as catalyst. Thermally driven catalytic decomposition will be conducted using synthetic natural gas representing realistic pipeline mixtures. Regeneration will be conducted by gasification, using carbon dioxide or water, separately or as mixtures. The experimental approach will systematically resolve reaction parameters and their interactions upon thermally driven catalytic decomposition metrics of methane conversion, hydrogen yield and product selectivity and key kinetic metrics: reaction rate, reaction order and activation energy. A similar approach will be applied to regeneration reactions, individually and coupled with thermally driven catalytic decomposition. Reaction rates will be correlated with carbon structure, thereby developing structure-activity relationships specific to both thermally driven catalytic decomposition and regeneration (gasification) reactions. Kinetic models for thermally driven catalytic decomposition and gasification – both resolved by carbon structure, will be developed with experimental input, using an open-source chemical kinetic modeling code. Fundamentally, this study seeks to connect carbon structure and activity as a fundamental metric for thermally driven catalytic decomposition and gasification reactions.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.