Hydrogen sorption properties of Pd-based nanoparticles - the role of alloying and internal structure

Licentiatavhandling, 2024

Nanostructures and nanoparticles are the fundamental building blocks for many nanotechnologies such as microelectronics, optical metamaterials, quantum technologies, catalysis and different kinds of sensors. Current fabrication methodologies for nanostructures enable an outstanding degree of control over their physical properties, such as size, shape and composition.

However, despite this high degree of precision, when studies of the physical and chemical properties of individual nanoparticles in an ensemble are performed, a striking variation in the response from a priori identical particles is often found. This variation reveals that there is more to these nominally identical systems than what is described by their size, shape and composition. To shed further light on what causes the individuality of such nanostructures, high precision measurements and huge sample sets are often needed to generate the required amount of statistically relevant data.

In the thesis, I present two different projects that aid in this endeavor by enabling the study of multiple different nanoparticle systems on the same sample, eliminating experiment-to-experiment uncertainties. In the first study (I), we have developed a microshutter tool for the nanofabrication of plasmonic metal alloys with single nanoparticle composition control on a single sample. We showcase how this technique has been used to investigate 38 different alloys each in 3 different binary alloy systems for their application in plasmonics and state-of-the-art plasmonic hydrogen sensing. In the second study (II), we have to different degrees deformed Pd nanoparticles in a systematic way on a single sample to investigate how the induced defects and plastic deformation affect the hydrogen sorption of the individual nanoparticles. This revealed the intricate interplay between particle morphology, internal structure and substrate interaction that decide the hydrogen sorption properties of supported Pd nanoparticles.