DEFECT ENGINEERING IN LAYERED MATERIALS: ELECTROCHEMICAL APPLICATIONS IN ENERGY CONVERSION AND BIO-SENSING

Restricted (Penn State Only)
Author:
Lei, Yu
Graduate Program:
Materials Science and Engineering
Degree:
Doctor of Philosophy
Document Type:
Dissertation
Date of Defense:
February 19, 2019
Committee Members:
  • Mauricio Terrones, Dissertation Advisor
  • Mauricio Terrones, Committee Chair
  • Joshua Alexander Robinson, Committee Member
  • Joan Marie Redwing, Committee Member
  • Thomas E Mallouk, Outside Member
Keywords:
  • 2D materials
  • defects
  • electrochemistry
  • Hydrogen evolution reaction
  • Lithium-ion battery
  • Bio-sensing
Abstract:
Extensive research efforts have been dedicated to the field of two-dimensional (2D) materials in a short period of time. From semi-metallic graphene, to semiconducting MoS2, to insulating hexagonal boron nitride (hBN), 2D materials provide a wide range of physico-chemical properties that can be engineered for diverse applications. Recently, defect engineering has emerged as a primary approach to tailor the physio-chemical properties and further extend the functionalities of 2D materials. This thesis aims to provide a comprehensive understanding of the synthesis, characterization, properties, and application of 2D materials’ defects in the context of electrochemistry fields. Chapter one provides a brief introduction of 2D materials, defect engineering in 2D material, and the corresponding electrochemical applications. Chapter two demonstrates a wet chemical approach followed by a thermal treatment at low temperature to realize the W doping/alloying in MoS2 lattice and heterostructure formation with graphene. The heteroatomic doping/alloying is able to activate the ‘inert’ sites for efficient hydrogen evolution. Chapter three demonstrates how the defect engineering in hBN can be used to transform hBN into catalyst support for Pt-based single atom catalysts (SACs) for hydrogen evolution. Chapter four and five demonstrates the importance of heteroatomic doping in MoS2 in other electrochemical applications including Li-ion battery and bio-molecule sensing. Finally, chapter six describes future work related to the defect engineering from an electrochemist`s perspective.