Reactive Chemical Systems: Catalysis under Nano-confinement
Abstract
Catalysis under nano-confinement: Using 1D and 2D systems to tune confinement effects Abstract Putting a catalyst into a narrow, confined system creates a different local environment around the catalyst and reactants/products than encountered in a bulk phase. The confinement geometry and chemical environment can affect a molecule to attain a specific conformation to adjust to the shape and reactivity of the confining material. The surrounding cavity can decrease the energy barrier of the reaction by inducing attractive interactions between the cavity and the reactant and between the cavity wall and a confined catalyst. Additionally, confinement can open new ways that it can occur. This means that if we understand the underlying principles we can tune the reactivity to improve the yield of the reaction for a desired product. Two reactions we will use to elucidate the effects of confinement are conversion of CO2 plus hydrogen to methane and the oxidative dehydration of ethane and propane. CO2 methanation is interesting because it is a pressure dependent reaction and confinement by straining the system will affect how the reaction occurs. It is also interesting as a process to ameliorate CO2 emissions. Oxidative dehydrogenation (ODH) of ethane and propane is interesting because ethylene and propylene are very important products made in an energy intensive processes and there is evidence that confinement can prevent loss of the product through overoxidation. Aside from the importance of these reactions, the point of this project is to obtain a fundamental understanding of confinement effects and how these can be applied to a wide range of reaction systems. The catalysts will be confined between 2D sheets, Graphene and Boron Nitride, that are linked together to adjust the spacing between the sheets. The main challenge to the study of these systems is that they are quite complex considering the number of possible interactions involved. Being able to follow the state of the catalyst and the species adsorbed on its surface is important for a fundamental understanding of catalysis under confinement. Techniques will be developed to allow gas phase species to be measured simultaneously with the state of the catalyst and the species on their surfaces. Theory will be used to detail reaction mechanisms and to interpret data from the spectroscopic measurements. Combined with the experiments this will allow us to generalize the rules we learn about confined catalysis to more general systems. We expect to uncover new and novel phenomena made possible by confinement.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Oct 19, 2022
- Source ID
- W911NF2310006
Entities
People
- Lisa Pfeffele
Organizations
- Army Contracting Command
- United States Army
- Yale University