PhD Dissertation Final Oral Defense (November 2024)

Title of dissertation: Advancements of MXene Based Nanocomposites as an Efficient Electrode Materials

Name of Candidate: Anum Iqbal
Program: PhD in Materials Science and Engineering
Name of supervisor:  Dr Nasser M. Hamdan,

Abstract:
Recent technologies for efficient energy conversion and storage purposes are acknowledged as realistic remedies for upcoming energy shortages. However, the high cost and limited efficiency of electrocatalysts provide an obstacle to the practical application of these technologies. Therefore, improving the performance of these electrocatalytic materials is essential to expand their uses. Transition metal hydroxides and oxides show high activity and stability in alkaline electrolytes, suggesting as a potential substitute for ultra expensive and rare metal oxides that includes Ruthenium/Iridium oxides. Nonetheless, these materials have intrinsic difficulties that limit their scalability, including low stability, ineffective conduction, and a low number of active sites. On the other hand, a new class of two-dimensional materials called MXenes has a unique combination of hydrophilicity, high electrical conductivity, and tuneable surface-active sites that transform them attractive preference for electrocatalyst applications. Nevertheless, MXene sheets are highly susceptible towards oxidation and self-stacking phenomenon that considerably diminish their electrical conductivity and stability in aquatic conditions under high voltages. Fortunately, it has been demonstrated that adding MXenes to other materials has synergistically increased the electrocatalytic activity of the resultant composites. In the first experimental plan of this thesis, a novel combination of TiO2 electrodes functionalized with Ti3C2Tx MXene was fabricated in order to boost the performance of photoelectrodes by improving photon absorption, charge segregation, and photocurrent production at the electrode surface. In the second investigation, the eximious activity and stability of tri-metal hydroxides for improved OER activity was successfully achieved by immobilizing the active sites at open pores of three-dimensional (3D) V2C MXene architecture. The morphologically unique V2C MXene substrate modulated the structural and compositional features of the synthesized composite for highly accessible active sites and improved charge transfer. The results achieved in this thesis interestingly justify the role of MXene for development of efficient electrode materials for energy related applications.

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