Functionalization of Two-dimensional Ti3C2Tx MXene and its Nanocomposites for Application in Catalysis and Optoelectronics

Abstract

This thesis explores the strategic modulation of surface defect states in Ti3C2Tx MXenes and their hybrid architectures to advance catalytic wastewater treatment, electrochemical hydrogen production, and broadband photodetection. Controlled chemical etching was optimized to tailor low-valent Ti3+ or oxygen-vacancy-rich defect sites in accordion-like, multi-layered Ti3C2Tx for efficient Fenton-based degradation of organic dyes. Phosphorus doping further enhanced the catalytic performance by suppressing nanosheet restacking and facilitating the formation of a porous aerogel, which promotes mass diffusion and the generation of reactive oxygen species. In addition, constructing Ti3C2Tx/Bi2S3 heterostructures enhanced interfacial charge transfer and light harvesting, enabling both catalytic reduction of organic contaminants and photoelectrochemical (PEC) hydrogen evolution. Furthermore, ultrasmall Ru nanoclusters anchored on N-doped, oxygen-vacancy-engineered Ti3C2Tx nanoribbons exhibited strong electronic metal-support interactions, improved photothermal response, and superior alkaline PEC hydrogen evolution activity. Finally, MXene/Bi2S3 Schottky junction photodetectors demonstrated efficient carrier separation and transport, delivering broadband UV-Vis-NIR (300-1550 nm) detection capability. Overall, this work establishes MXene-based defect engineering and heterostructure design as powerful routes for multifunctional environmental remediation and sustainable energy applications.