Garrett Mitchell

Graduate Research Assistant

Co-advised by Professors Fabio Ribeiro
and W. Nicholas Delgass

Professional Networks



Background

Education

California State Polytechnic University, Pomona , Bachelor of Science in Chemical Engineering (2015)
Purdue University, Ph.D. Chemical Engineering (2015 - present)

Experience

  • University of North Dakota, REU student (Summer 2014)

Awards

  • Andrews Fellowship (2015)
  • Kellogg Honors College (2011-2015)
  • Summa Cum Laude (2015)

About Me

I was raised in Buena Park, CA and I obtained my B.S. in Chemical Engineering at California State Polytechnic University, Pomona in 2015. I started attending Purdue in August of 2015 and intend to graduate May 2020. In my final years there at Cal Poly Pomona, I investigated Colloid Coagulation and maximum heat capacity behavior with IET equations alongside Dr. Lloyd Lee. In my final summer I worked on hydrothermal degradation of Lignin using doped catalysts during an REU at UND. My education at Purdue has taught me how to be a more independent, curious researcher as well as a better person I believe. In my off hours (and vacations) I enjoy scuba diving, computer building, 3D printing, D&D and hiking.

Project Description

The size and shape of nanomaterials are known to play a crucial role in improving catalytic activity: Reduction in size often leads lead to higher activity per unit mass of the catalyst due to increased surface area but due to concomitant increase in surface free energy, there is a higher tendency to sinter. The high temperature and reactive conditions encountered during catalysis often accelerate the sintering process, which results in a loss of active surface area of the nanoparticles, causing an undesired catalyst deactivation. An unwanted shape change may further pose a threat to the activity. Apart from the shape/size, tuning the metal-support interactions (MSI) of catalysts is also a key factor in improving functionality of catalytic systems. Understanding these factors in catalysts can lead to better understanding of the materials to the overall goal of improving the overall activity under reaction conditions.

  • DMREF: Design of Multifunctional Catalytic Interfaces from First Principals

    Au and Pt nanoparticles (NPs) supported on metal oxides represent a system important for the water-gas shift reaction. Over the past two decades, there have been numerous of studies on the bonding between gold/platinum and metal oxide supports showing not only high catalytic activities, but also high stability against sintering. Often abrupt changes in activity has been observed at higher temperatures over 350 °C, therefore, studying the evolution of shape/size with temperature is important to correlate the high temperature catalytic activity with its respective shape/size. To this end, I have worked on employing many methods to understand this system including: UTEM in-situ laser heating, ACSTEM characterization, kinetic analysis and EDS.

  • TEM Characterization of Au/TS-1 for use in Partial Oxidation Catalysis

    Since Haruta reported that Au nanoparticles (NPs) on titania supports could be used to produce PO directly from hydrogen, oxygen and propylene, with water and CO2 as the only byproducts, there has been increasing interest in using these catalysts to make PO. However, whether or not the most relevant Au active sites in the Au/TS-1 for PO are the Au small enough to fit within the pores is an issue that has yet to be resolved. There is indirect evidence of the existence of these particles via Au AAS measurements of samples that show no Au particles on the surface. Experiments where TS-1 seeds are coated with a S-1 shell, then Au deposited, also proves the existence of these particles. Although, by this indirect evidence, it is known that these particles exist, it is necessary to provide direct evidence of these particles in the pores to complete the story, as well as to provide some way to measure the relative activity of these small Au nanoparticles in the pores <.5 nm when compared to the traditional 1-2 nm particles on the outside surface, and high resolution scanning transmission electron microscopy (HRSTEM) has the possibility to give this direct evidence. We have been working on direct high-resolution images of these Au samples will also make quantifying the Au active site for turnover rates and numbers possible, since as of yet, the Au active sites are not well understood.

Recent Publications