60th Annual Report on Research 2015

In the first year of grant funding, we have carried out two parallel advances: theoretical/computational advances, and simulations. The simulation advances relate to preliminary small-scale simulations of the γ-Al₂O₃surface (clean, Phosporus-doped, and hydroxylated). This simulations are now part of a draft that will be submitted for publication soon. We have also ventured in simulating other kinds of metal oxides (such as Indium oxide), which will also be part of a manuscript. Theoretical/computational advances were implemented in order to successfully achieve the large-scale computations needed in the simulation stage that will be embarked on in year 2.

Theory/Computational methods development

To approach the simulations of realistically sized multilayer composites, such as a realistic catalytic system, several computational methodologies had to be developed. In doing so, the postdoctora fellow supported by the grant successfully brought to publication two important advances in the field of Density Functional Theory (see references by Krishtal et al.). The new computational protocol developed is allowing us to consider realistically sized model systems of Hydrotreating catalyst-substrate interfaces.

Simulation of the catalytic system

In our simulations, we have considered the spinel model of γ-Al₂O₃ by Pinto et al.. As the activity of γ-Al₂O₃ surface is influenced by the amount of coverage of hydroxyls on the surface, we have studied it for several levels of OH coverage. Comparison of InfraRed (IR) spectra shows that the morphology of the simulated surfaces is in agreement with the experiments.

We are in the process of simulating the previously generated partially hydroxylated γ-Al₂O₃(including its phosphorus-doped modification) in their ability to modify the polarizability of deposited Molybdenum Sulfide. This is ongoing work which is being carried out by the PI, the Postdoctoral Fellow and a Graduate student.

Impact on the PIs career

The PI has benefitted tremendously on working towards achieving the goals proposed in the ACS-PRF proposal. The ACS-PRF grant opened the way for the PI's research group to building expertise in modeling metal oxide surfaces - a completely new field of research for the PI. In addition, new computational methods needed to be developed to be able to approach the full model system. This gave the PI strong visibility in the theoretical chemistry/condensed matter physics community. In addition, the work on Hydrotreating is proving to be much richer of novel physics that previously thought. The capability of Alumina to be doped with nonmetals is novel and has already drawn attention from industry and academics alike. The possibility of tuning the polarizability of adsorbed species by controlling the doping level also is an innovative solution and offers alternative paradigms for chemical and physical processes at metal oxide surfaces.

Broader Impacts

The ACS-PRF grant funded a postdoctoral fellow position (Dr. Alisa Krishtal). The student was given the opportunity to work on a inherently multidisciplinary problem with potential for repercussion in the real world. Training involved an initial phase for mastering the basics of the hydrotreating process and then a phase for technical/scientific training on simulations of metal oxide interfaces. The student presented the work on both theory deveopment and simulations at the ACS national meeting in San Francisco in August 2014. We are planning to attend and present an update on the progress of our simulations at the ACS national meeting in San Diego to take place in March 2015. Certain minor aspects of the ACS PRF project were carried out by undergraduate student, Mr. Saad Arshad, supervised by the PI and by the postdoctoral fellow, Dr. Alisa Krishtal.