CDS&E: Multiscale Process Intensification of Direct Catalytic Hydrogenation of CO2 to Hydrocarbons via Cooperative Tandem Catalysis

Significant research efforts are currently underway to develop new chemical manufacturing technologies that have the potential to decarbonize the energy and chemical industries, maintaining the prominent role of the U.S. in producing valuable chemical products and transportation fuels. Key to this continuing advance is the development of “intensified” chemical processes that combine what traditionally were multiple processing steps into a single, multifunctional operation, facilitating energy savings and cost reductions - process improvements that have broad applicability to energy, chemicals, and other manufacturing sectors. The catalyst and process design methods proposed in this research program also facilitate the development of modular manufacturing processes, increasing the efficiency, flexibility, resilience, and overall competitiveness of chemical manufacturing supply chains. With the recent revolution in domestic shale gas production, new routes to using novel catalytic systems that effectively promote a sequence of reactions (rather than a single reaction) will open the door to potentially disruptive process intensification technologies for shale gas conversion and new pathways to creating a hydrogen-based economy. This research program will support the recruitment of traditionally underrepresented students both at the graduate and undergraduate levels. An outreach activity is planned that will teach the importance of sustainable design to 1st–4th graders. The research findings will be integrated into a new graduate-level course. This project will establish the foundation of a new direction in process intensification through the development of cooperative tandem catalysts, catalysts that promote sequences of chemical reactions rather than a single reaction. Specifically, this research will address the following fundamental questions: How do multiple catalysts interact and affect individual catalytic performances in a tandem reactive process at the micro-, meso- and macro/process-scales? When is tandem catalysis desirable? How can the optimal combinations of tandem catalysts be predicted? How are multi-catalytic systems designed, synthesized, and tuned to perform a series of reactions while ensuring the desired product quality, stability, and performance at the process level? As a representative tandem catalytic system, hydrogenation of CO2 over metal oxides to produce methanol will be integrated with zeolite frameworks that selectively transform methanol to C2+ chemical products, specifically C2-C4 olefins and C5-C18 hydrocarbons. Chemical transformation of CO2 with H2 into fuels, chemicals, or chemical precursors constitutes a conceptual evolution in achieving sustainable chemical production and expediting the “green energy” transition. To better understand the interactions among reaction chemical species and the tandem catalysis, the research team plans to develop, validate, and analyze mechanistic models at the density functional theory (DFT) level and translate the results of the DFT simulations into the rate and equilibrium constants of microkinetic models. To elucidate how microscopic changes affect the macroscopic properties of a tandem catalyst system, a unique method based on order parameter analysis (originally developed in the context of studying phase transitions) will be formulated to reduce the complexity of the multi-scale reactor models. Understanding how the properties of catalysts influence the merging of reaction processes will facilitate the design and control of intensified processes, thereby saving significant time and investment for new chemical product discovery. 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.