First Principles Computations of Interfacial Phenomena for Environment-Friendly Catalysis
EMSL Project ID
35193
Abstract
A fundamental knowledge of the chemical and physical properties at gas-solid or liquid-solid interfaces is essential for the design and discovery of breakthrough materials for cleaner and more efficient catalysts. Computational strategies using high performance computing provide the opportunity to design surfaces and interfaces with desired functionalities. This requires both an understanding of the processes that are occurring at the interfaces as well as relating catalytic properties to key calculated parameters such as adsorption energies, which can be used in screening many potential candidates. This proposal is focused on both the understanding of structure-function relationships as well as use of this insight to help design new materials for processes involving heterogeneous catalysis, electrocatalysis, and photocatalysis. The computational studies will be based on state-of-the-art electronic structure methods including density functional theory, a powerful tool for understanding and design of new catalysts. The proposed computational studies involve collaboration with world-class experimentalists at the Pacific Northwest National Laboratory and Argonne National Laboratory. New catalysts are needed for making and breaking specific bonds for energy efficient and environmentally friendly catalysts. Recent studies have shown that supported subnanometer clusters exhibit novel catalytic properties for breaking C-H bonds. We will carry out systematic studies to explore the unusual catalytic properties of these clusters and to determine how they might be tailored to make and break specific bonds. These computations will play a key role in the design and discovery of environmentally friendly catalysts for industrial processes. Another interesting area of heterogeneous catalysis is synthesis of nanocarbons, which have many potential applications.
Electrocatalysis provides a low-temperature, energy efficient alternative to heterogeneous catalysis that has potential uses for chemical transformations as well as the development of alternative energy sources. We will investigate carbon dioxide electroreduction, wherein CO2 is electrochemically reduced to CO and hydrogenated products in acidic solution. This reaction has the potential to both produce useful chemicals from an essentially limitless feedstock and reduce atmospheric greenhouse gas loadings. Among the most exciting possibilities presented by this reaction is the electrochemical production of methanol. We will also investigate oxygen reduction catalysis, which is important for energy conversion by fuel cells.
A third focus of the proposed work is photocatalysis. Efficient utilization of solar energy through photocatalysis would be a significant step towards easing current energy demands. TiO2 is a prototypical photocatalyst used for organic pollutant degradation and also for water splitting (H₂O → H₂ + ½O₂), H2 being an important fuel source. Despite the importance of TiO2, there are many fundamental issues that are not well understood, such as how photoexcited holes and electrons interact with surface adsorbates and lead to their catalytic decomposition. Molecular modeling methods provide an excellent way to study surface reactions and provide insights into the intermediates and reaction pathways. We will study the reactivity of organic molecules over TiO2, better characterize the nature of electrons/holes and their transport properties, and model the interactions of holes/electrons at the surface in the presence of adsorbate molecules.
Project Details
Project type
Capability Research
Start Date
2009-10-01
End Date
2012-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members