CAREER: Catalytic Resonance-Enhanced Activation of Hydrocarbon Resources

University Of Houston, Houston TX

Investigators

Abstract

Leveraging the recent abundance of U.S. shale gas resources as a chemical production feedstock requires the use of catalytic upgrading strategies. Constraints related to chemical composition and geographical distribution of both the feedstocks and products require the development of innovative catalytic strategies that can take advantage of these new resources. Motivated by the continuous growth of cost-competitive renewable electric power, the use of electrochemical strategies to enable the activation of hydrocarbon resources provides a unique opportunity to reduce the environmental impact and cost of chemical manufacturing by avoiding the high pressures and temperatures synonymous with thermally driven chemical transformations. Furthermore, the electrochemical approach is more resistant to major disruption events that pose resilience and safety threats in traditional chemical manufacturing supply chains. Therefore, the development of electrically driven chemical reaction strategies in this research program has significant transformative potential. Direct electrochemical catalytic upgrading of hydrocarbon resources, however, currently is limited by both slow reaction rates and poor selectivity to desired products. This study will advance the development of catalytic resonance, whereby the energetics of a catalyst is modulated in time to maximize the reaction rate and selectivity towards the desired product. This study will integrate concepts of sustainable chemical transformation, renewable energy sources, and catalytic kinetics into an educational plan that will engage students both at UMass and the surrounding area. The impact of outreach efforts will be expanded by developing educational online content, using simple and effective teaching techniques to communicate the fundamental science behind energy related applications. This study will focus on developing a fundamental understanding of catalytic resonance for the electrochemical oxidation of hydrocarbons into value-added oxygenates. While renewable and cost-effective energy to drive the electrochemical reactions is readily available, the rate of catalytic turnover associated with the electrochemical oxidation of hydrocarbons (e.g., alkanes, alkenes) limits the approach. Metal catalysts that do exhibit appreciable electrocatalytic activity are plagued by the lack of selectivity to partial oxidation products due to the over-oxidation of hydrocarbons into carbon dioxide as an undesirable product. Under steady-state conditions, the challenges to catalytic activity and selectivity share a similar origin: balancing the necessary adsorbate coverages, kinetic driving force, and the combination of faradaic and non-faradaic elementary steps involved in the catalytic cycle. Controlled energetic oscillations of the catalytic working electrode decouples the rate-determining factors, allowing for their independent tuning by accessing non-equilibrium states that cannot be sustained under static conditions. While this study will focus on hydrocarbon oxidation, the work will develop the understanding and capabilities needed for extending the concept of catalytic resonance to other important chemical transformations. 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.