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Master’s Thesis Defense - Christopher Arnold
MSE Grad Presentation
Monday, April 9, 2018 - 2:30pm
Love Building, Room 210
Committee Members: Prof. Faisal Alamgir, Advisor, MSE Prof. Matthew McDowell, MSE Prof. Antonia Antoniou, ME
“The Synthesis of Atomically Thin Pt Monolayer to Multilayer Pt Films on Graphene and MoS2”
In the area of catalysis, substantial research is aimed at exploring the influence of the size and morphology of precious metal nanoparticles as well as catalyst supports on reaction kinetics. Recently, this has evolved into depositing highly wetted monolayers/multilayers (ML) of precious metal onto various catalyst supports. Similar to nanoparticles, ML growth significantly reduces precious metal loading (therefore improving cost) but additionally enhances catalytic activity with a better surface area to mass ratio and encouraging the substrate to tune the catalyst’s electronic properties via ligand effects and strained lattice geometry.
This work explores the deposition of Pt-ML on graphene in full 3D and 2D MoS2 as well as the influence of the Ni substrate ligand effect in electrocatalysis. Commercially available, Ni foam was utilized as a substrate for the 3D graphene growth before Pt was deposited layer-by-layer in a surface-limited electrochemical scheme to achieve highly wetted and atomically thin growth. A similar surface-limited technique was utilized for the deposition of Pt on both vertically and horizontally aligned MoS2. High resolution TEM, XPS, SEM/EDX, and electroanalytical techniques were used to characterize these samples and reveal the evolution of the atomic/electronic structure as a function of Pt-ML thickness. It is demonstrated that the synthesis scheme outlined here allows for the design of dimensionally-controlled and ligand-flexible catalyst architectures that can have a wide range of chemical applications.