11:00 AM - 12:00 PM
Dr. Sebastian Zuluaga, Wake Forest University Materials Science and Technology Division, Materials Theory Group
Building 4100, Room J-302
Email: Valentino CooperPhone:
The main objective of this work is to gain a basis for the rational design of catalysts used in fuel cells for the conversion of chemical energy stored in hydrogen molecules into electric energy, as well as photo-catalysts used for hydrogen production from water under solar irradiation. This objective is achieved by applying the first principles computational approach to reveal the relationship among compositions of materials under consideration, their electronic structure and catalytic activity.
In the first part of this talk, I will address the Pd-based alloys and layered structures. The O and OH binding energies are chosen as descriptors of the ORR. These systems have been studied as promising electro-catalysts for the ORR on the fuel cell cathodes. In order to study these systems, I link the activity of a surface toward ORR to computable thermodynamic properties of the system and further to the binding energies of the ORR intermediates on the catalyst surface. A more challenging task is to find how to tune these binding energies through modification of the surface electronic structure that can be achieved by varying the surface composition and/or morphology. To resolve this challenge, the electronic structure, binding energies of intermediates and the ORR free energies have been calculated within the density functional theory (DFT) approximation.
Regarding the problem of the hydrogen production via photo-catalytic splitting of water, one of the challenges is tuning the band gap of the photo-anodes to optimal levels. Graphitic carbon nitride (g-C3N4) is a promising material to be used as a photo-anode; however, a reduction of the band gap width by rational doping of the material would improve the efficiency significantly.