H2O2 interaction with amorphous TiNiSn

Sammanfattning

The growing demand for sustainable energy solutions has increased interest in thermoelectric materials that convert waste heat into electricity via the Seebeck effect. Half-Heusler alloys, such as titanium nickel tin (TiNiSn), are particularly promising due to their cost-effectiveness, high thermoelectric performance, and engineering adaptability. TiNiSn’s thermal stability and favorable Seebeck coefficient make it highly efficient for heat-to-electricity conversion. These energy-efficient properties enable its application in various fields, including heating systems, automotive exhaust recovery, industrial processes, and sensor technology. TiNiSn as thermoelectric sensors, used in environmental monitoring, fitness tracking, and skin health applications, highlight the importance of understanding material interactions with biological environments. In particular, sensors designed for detecting inflammatory skin diseases may be exposed to hydrogen peroxide (H₂O₂), a reactive oxygen species associated with oxidative stress and inflammation. Understanding how external chemical species interact with TiNiSn surfaces is essential for optimizing their stability and performance. This master’s thesis investigates the interaction between amorphous TiNiSn and H₂O₂ using density functional theory-based molecular dynamics simulations to explain these interactions and their implications for biocompatible thermoelectric applications. Radial distribution function analysis validated the short-range structural order of amorphous TiNiSn. Atomic reactions were explored by varying the number of H₂O₂ molecules interacting with the amorphous TiNiSn surface. Results revealed that H₂O₂ molecules diffuse, dissociate, and form hydroxyl groups on the amorphous TiNiSn surface, driven by the reactivity of underlying atoms. These findings highlight the interactions of H₂O₂ on the surface of amorphous TiNiSn, including dissociations, predominant oxidation in the formation of Ti-OH, Ni-OH and Sn-OH, and occasional reduction processes associated with H₂O formation on the surface. Increased H₂O₂ concentrations induce the formation of complex networks. Electron density distribution plots revealed that TiNiSn exhibits metallic and covalent bonding, while the interaction of OH with the system is characterized by ionic bonding. This research lays the groundwork for further exploration of amorphous half-Heusler alloys in advanced technological and eco-conscious applications.