Synthesis and Kinetics of Intermetallics and New MAX MXene
Within solid-state chemistry, understanding how a reaction occurs and what affects the reaction pathway gives insight into controlling reactions to produce materials with specific phases, microstructures, or properties. This is especially the case with rapid approaches, such as combustion synthesis, where the reaction is driven by the inherent exothermicity in the system, rather than a predefined heating pattern. To demonstrate this, I will first focus on the Ni/Al reactive system as a model for combustion synthesis kinetics, in addition to switching reaction pathways.
Following this, I will discuss a novel class of materials, MXenes. MXenes are potentially the largest class of 2D materials discovered so far. With a general formula of Mn+1XnTx, M is an early transition metal (Ti, V, Nb, Ta, etc.), X is C and/or N, Tx represents the surface groups (-O, -OH, -F, -Cl), and n = 1–4, over 30 stoichiometric phases have already been discovered, with many more predicted computationally. This class of materials has been widely studied owing to their exceptional properties, including hydrophilicity, scalability, mechanical strength, thermal stability, redox capability, and ease of processing. Because MXenes inherit their structure from Mn+1AXn (MAX) phase precursors, understanding MAX phase synthesis leads to control over flake size, defect density, and chemical composition of the resultant MXene. One understudied, yet important class of MXenes are solid-solution MXenes, where multiple elements are randomly distributed within the M layers. Herein, a set of multi-M chemistries (Mo, V, Ti, Nb) are used to study the effect of structure and chemistry on MXenes. While solid-solution MXenes have unique and tunable chemical, optical, and electronic properties, they also enable the formation of novel MXenes that cannot exist otherwise. By choosing specific chemistries, we can then begin to understand fundamental aspects of MXene chemistry and structure.
Hosted by Professor Wilma Olson
~Coffee/tea will be served prior to the lecture~