Aerosol Synthesis and Characterization of Heterogeneous Bimetallic Nanoparticles

Exploring aerosol technology to create bimetallic nanoparticles, including core-shell and Janus nanoparticles. Heterogenous nanoparticles implement multiple functionalities within the same nano structure, with interest in fields like catalysis, biomedicine, and sensors.

The development of new technologies and conservation of resources is important for a sustainable future. Nanotechnology, which deals with research and use of nanoscale material (one billionth of a meter), addresses these challenges. By breaking down materials into smaller components, nanotechnology enhances resource efficiency. Nanoparticles, objects smaller than 100 nanometers, are integral to this field and form naturally during processes like combustion and cloud formation. These nanoparticles are part of aerosols, gas-particle mixtures, studied in aerosol technology.

This thesis delves into the creation and characterization of segregated nanoparticles using aerosol technology. Two common types are "core-shell" and "Janus" particles. These heterogeneous nanoparticles can have multiple functionalities within the same structure, with interest in biomedicine, catalysis and sensors. The work explores methods like surface segregation and condensational growth to create these nanoparticles. First, particles aerosol nanostructures are created with spark ablation. Spark ablation uses electrical discharges, similar to those you see in loose electrical connections, to knock out atoms from electrodes whose material determine the particle compositions.

Surface segregation is like how water and oil separates. By heating spark made nanoparticles of immiscible materials, copper and silver in our case, both Janus and core-shell particles can be produced. Condensational growth is similar to how clouds form in the atmosphere when water vapor condenses on small particles. Here, we condense zinc and indium onto gold particles in custom setups to study the nanoparticle growth in situ.

This work is a development and specialization of previous methods in aerosol technology to create custom nanoparticles, focusing on segregated nanostructures including core-shell particles. We have already explored using these structures for semiconductor growth, which is a large field with many applications. The goals are that the methods described here can be further developed, and that the structures they can create can be tested and optimized for applications including catalysis and materials technology.