September 2020 Kentucky Lake Section Meeting

Tuesday, September 15th, 2020
Dinner @ 6:00 pm, Presentation @ 7:00 pm
Dinner Price is $10 (Students $5)

Live at Union University
Carl Grant Events Center
Jackson, TN 38305

– OR –
Join Virtually via Zoom
(Meeting ID TBA)

Dinner:  Caesar Salad, Beef Lasagna, Monterey Chicken, Scalloped Potatoes, Sweet Corn, Chocolate Explosion

Program: Transition metal dichalcogenides for applications in hydrogen evolution reaction, CO2 reduction, and photoluminescence spectroelectrochemistry

Speaker: Lyndi Strange, 5th Year PhD Candidate at University of Alabama

Abstract:  Transition metal dichalcogenides (TMDs) are semiconductors of the form MX2, where M is a transition metal (Mo, W, etc.) and X is a chalcogen atom. They are typically structured in hexagonal layers of M atoms sandwiched between two layers of X atoms. Two-dimensional TMDs (2D-TMDs) consist of a single layer of atoms have the structure X-M-X and have electronic properties that differ from the bulk material. For instance, the bandgap of MoS2 changes from an indirect bandgap in the bulk to a direct bandgap as a monolayer. In the search for better catalysts for renewable energy, TMDs have emerged as an interesting and promising catalyst for several avenues of alternate energy such as photovoltaic water splitting anodes, hydrogen evolution reaction, CO2 reduction, photovoltaic absorber layers, and protective layers for photovoltaic devices. The structure of the TMDs can also be tuned at the monolayer level to increase catalytic activity by doping and introducing defects, which has been shown increase activity towards electrocatalytic hydrogen reduction. The highly tunable structure also leads to tunable optical properties that in useful in next generation optoelectronics such as light emitting diodes (LEDs), field effect transistors (FETs), and ultra-sensitive molecular sensing due to their unique surface-sensitive optical properties. Learning how the structure affects the catalytic and optical properties serves as an important area of research in order tune TMDs to produce more efficient catalysts and serve in various optical applications. This research presentation will cover the following projects: 1) the proton reduction activity of 2D and bulk MoS2 using scanning electrochemical cell microscopy (SECM) and other electroanalytical techniques such as rotating-ring disk electrode and Tafel slope analysis; 2) examining the redox properties of 2D MoS2 using photoluminescence spectroelectrochemistry and scanning electrochemical cell microscopy (SECCM); 3) using aqueous liquid-phase exfoliation technique to produce MoS2 thin films for use in CO2 reduction and the characterization of the reaction products.

Speaker Bio:  Lyndi Strange graduated from Union University in 2016 with a B.S. in chemistry. She did two years of summer research under Dr. Joshua Williams studying guest-host relationships in dye included crystals. She also did a summer REU program at the University of Oregon under Dr. Shannon Boettcher studying the electronic properties of GaAs microstructures grown using close-spaced vapor transport (CSVT), which inspired her to pursue electrochemistry as her focus in graduate school. She is currently a PhD candidate entering into her 5th year at the University of Alabama studying under Dr. Shanlin Pan. Her research focus at UA has focused on transition metal dichalcogenides for use in alternative energy and spectroelectrochemical applications. She has co-authored and authored articles in the ACS Energy Letters, the Journal of Physical Chemistry Letters, and has submitted a review article Journal of the Electrochemical Society. During her tenure at UA, she also participated in a summer internship at Sandia National Laboratories in Albuquerque, NM, which lead to a year-round position. She plans to graduate from the University of Alabama in Summer 2021 and hopefully continue her Sandia employment as a post-doctoral appointee.

 

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