Elucidating Oxophilic Pathways of Enhanced Epoxidation Reactions by Optimization of Ag Assemblies on Bifunctional Copper-based Catalysts
Dr. Ashleigh Baber1, Associate Professor
Co-PI(s): Kendra Letchworth-Weaver1, Sanjaya Senanayake2
1: James Madison University, Harrisonburg, VA 22807
2: Brookhaven National Laboratory, Upton, NY, 11973
Selective catalytic oxidation is a key process that impacts numerous reactions steered through active sites and beyond to yield desired chemical products of value. Atomic level design of such sites is key to improved efficiencies and mitigation of waste. For instance, the transformation of ethylene into ethylene oxide and propylene into propylene oxide are super selective reactions which are valued at $77 billion on the global market. It is critical that reactions occurring on this scale have high selectivity to mitigate greenhouse gas emission, like the formation of carbon dioxide (CO2). Currently, silver (Ag) and copper (Cu) materials are used to catalyze the production of ethylene and propylene oxide. High selectivity can be achieved when a second element is added to the Ag and Cu catalysts. Unfortunately, the addition of a second element to catalysts is expensive and, in some cases, toxic yet may not yield improved reactivity. Recently, the use of AgCu bimetallic materials have gained significant attention due to their selectivity enhancement of these reactions. Many questions still surround the highly selective AgCu bimetallic catalysts, including: what happens to the AgCu material during the reaction of ethylene?; what kind of oxygen species are useful for forming ethylene oxide?; and how does ethylene look as it transforms to ethylene oxide?
To answer these questions, experimental, theoretical, and educational approaches used to investigate the objectives will harness the combined expertise of the PI’s Baber, Weaver, and Senanayake forming a unique partnership between an undergraduate research institution (James Madison University, JMU) and national laboratory capabilities (Brookhaven National Laboratory, BNL). To investigate the reactivity of the catalysts, temperature programmed reaction spectroscopy and reactor kinetic testing using gas chromatography-mass spectrometry will be used. Density functional theory (DFT) calculations will be used to investigate the structure and energy of ethylene and the intermediates formed on the way to becoming ethylene oxide on the surface of AgCu catalyst.
This project will leverage advanced in situ facilities at BNL, including ambient pressure X-ray photoelectron spectroscopy (AP-XPS) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), which JMU undergraduate researchers will utilize. This project will benefit faculty and students from JMU as we build upon existing research capacity as a newly minted R2 institution and give undergraduates hands-on research experience at JMU and BNL.
This research was selected for funding by the Office of Basic Energy Sciences
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