Overview
Our lab is interested in developing new catalysts for efficient and sustainable production of fuels and chemicals via fundamental understanding of reaction mechanisms and structure-function and composition-function relations. We combine experimental and computational approaches to develop such relations.
Selective Oxidation of Small Hydrocarbons on Metal Oxides
The shale gas revolution has made small alkanes (methane, ethane, propane, butane) highly abundant. The conversion of these alkanes to high value alkenes is currently achieved in industry via energy consuming endothermic non-oxidative processes that are economical only at large scales and suffer from limitations such as carbon formation. This project is focused on alternative oxidative processes, which if performed with high selectivity can lead to more energy efficient smaller scale processes. A significant focus of this work is on transition metal oxides with small pores for understanding how pore-confinement effects influence selective oxidation catalysis.
Project Goals:
1. Understanding what properties of molecules and lattice oxygens of oxide catalysts determine reactivity and selectivity
2. Understanding how pores of molecular dimensions influence catalysis and make dehydrogenation more selective than O-insertion reactions.
3. Developing new selective oxidation catalysts that utilize pore confinement effects.
Vinyl Acetate Synthesis on Pd-based Catalysts
Vinyl acetate monomer is a high-value chemical made from oxidative coupling of ethylene and acetic acid on palladium-based nanoparticle catalysts under high coverage of surface acetates. Majority of the acetic acid produced world-wide is used for this reaction. Our work seeks to advance mechanistic understanding and develop improved catalysts of this reaction, and to utilize this reaction as a model system to understand how high coverage can be leveraged for selective catalysis.
Project Goals:
1. Understanding how lateral interactions between molecules and elemental composition of catalysts together influence reactivity and selectivity in catalysis under high coverage.
2. Developing new single atom alloys catalysts for more efficient catalysis.
Ab-inito dynamics of co-adsorbed ethylene and acetate species
Selective Oxidation Properties of AgCu Near Surface Alloys (NSAs)
Ag and Cu do not mix significantly in the bulk but Ag can form stable monolayer on Cu surfaces under reducing environment, with a well-defined structure and unique electronic and catalytic properties. Surface science studies have shown that O2 molecules dynamically restructure the NSA to expose Cu atoms in the surface Ag layer. Such restructuring is reversible upon removal of surface O-atoms. We seek to utilize such restructuring and the electronic properties of the NSA for efficient selective oxidation catalysis.
Project Goals:
1. Understanding how the electronic structure of the NSA and and the dynamic restructuring influence selective epoxidation catalysis.
2. Developing nanoparticle analogs of AgCu NSAs formed in surface science single-crystal studies.
Infrared Spectroscopy Methods
Project Goals:
1. Understanding how optical interference effects in multilayer thin-films enhance infrared absorption signal from molecules.
2. Designing multilayer substrates for highly sensitive infrared spectroscopy.
