4th Year Seminar: “Computational prediction of MXenes for hydrogen chemistries” with Yamilee Morency

Yamilée Morency, PICS Chemical and Biomolecular Engineering Ph.D. student and advisee of Dr. Aleksandra Vojvodic, will be presenting a 4th year seminar in Towne 225, Raisler Lounge on Friday, February 16th at 12:30 PM. Lunch will be provided for up to 40 individuals.

Read more about Yamilee’s seminar below.


Computational prediction of MXenes for hydrogen chemistries


To combat climate change and phase out fossil fuels, hydrogen has been proposed as an alternative fuel source because it releases no CO2 when it burns and is 3 times more energy dense than hydrocarbons (gravimetric). Two challenges to a hydrogen economy are hydrogen storage and hydrogen production. According to the DOE Hydrogen Earthshot target, we should be aiming for systems capable of storing at least 4.5% hydrogen and clean hydrogen that costs $1/kg. MXenes have been shown to be capable of some hydrogen storage. However, there is a demonstrable gap concerning where in the MXene is hydrogen stored, how is it stored (as H or H2) and how much hydrogen can be stored in a particular MXene. To bridge this gap, we came up with a framework that systematically explores hydrogen in MXenes using Ti2C and Ti3C2 as starting models through Density Functional Theory (DFT) calculations. We look at two levels of complexity stoichiometric vs nonstoichiometric Ti2C and Ti3C2. We also look at how hydrogen storage changes through tuning the terminations (N, P, O, S, Se, F, Cl). We then apply that framework to MXenes in which we change the metal to Zr, Hf, V, Nb, Ta, Mo, W . In the end, we have been able to show that hydrogen storage in MXenes is possible but is highly vacancy, metal, and termination dependent. MXenes have demonstrated some hydrogen evolution reaction (HER) capabilities, however they do not quite reach the effectiveness of Pt nanoparticles. Herein, we are attempting to bridge the gap between MXene and Pt nanoparticle by reducing the dimensionality of MXenes to expose new catalytic sites for HER.