Mechanical activation of van der Waals materials at cryogenic temperature
Restricted (Penn State Only)
- Author:
- Fest Carreno, Andres
- Graduate Program:
- Materials Science and Engineering
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- December 10, 2024
- Committee Members:
- John Mauro, Program Head/Chair
Mauricio Terrones, Chair & Dissertation Advisor
Bert Chandler, Outside Unit & Field Member
Joan Redwing, Major Field Member
Joshua Robinson, Major Field Member - Keywords:
- Mechanical activation
cryomilling
van der Waals materials
hydrogen evolution reaction
graphite
molybdenum disulfide - Abstract:
- For a long time, van der Waals (vdW) materials and their monolayers have been studied as catalyst supports. While their unique properties have led to numerous reports of outstanding performance, their widespread application remains restricted by limitations in the synthesis methods currently available. Mechanical activation by milling cryogenic temperature, also known as cryomilling, offers a versatile approach for defect generation in vdW materials, enhancing their chemical reactivity and opening the door to facile synthesis methods, as recently reported for hexagonal boron nitride. The present work explores cryomilling as an alternative method to activate graphite and molybdenum disulfide (MoS2) for their use as supports in the synthesis of hydrogen evolution reaction (HER) catalysts. Chapter 1 presents a brief introduction to vdW layered materials. In Chapter 2, the impact of cryomilling on the crystallinity and defect density of graphite and MoS2 is discussed in relation to observed increases in reactivity. Chapter 3 discusses the use of cryomilling-activated graphite and MoS2 for the reduction of platinum (IV) chloride, with emphasis on the final oxidation state achieved under different experimental conditions, and evaluates the performance of the synthesized materials as electrocatalysts for the hydrogen evolution reaction. Finally, Chapter 4 presents some potential lines for future work, regarding the use of mechanically activated vdW materials.