From sparks to nanoparticles: controlling composition at the nanoscale
(2026)- Abstract
- Nanoparticle properties depend strongly on composition, making precise control essential for applications in catalysis, sensing, and electronics. By combining two or more elements in a single particle, synergistic properties can emerge that are inaccessible to the individual constituents. Realising these benefits, however, requires reliable methods for tuning composition at the nanoscale.
This thesis investigates how the composition of nanoparticles generated by spark ablation can be controlled. Spark ablation is a continuous gas-phase synthesis method that produces particles with relatively clean, chemical-free surfaces, from virtually any conductive material. Despite its versatility, achieving predictable compositional control during... (More) - Nanoparticle properties depend strongly on composition, making precise control essential for applications in catalysis, sensing, and electronics. By combining two or more elements in a single particle, synergistic properties can emerge that are inaccessible to the individual constituents. Realising these benefits, however, requires reliable methods for tuning composition at the nanoscale.
This thesis investigates how the composition of nanoparticles generated by spark ablation can be controlled. Spark ablation is a continuous gas-phase synthesis method that produces particles with relatively clean, chemical-free surfaces, from virtually any conductive material. Despite its versatility, achieving predictable compositional control during spark ablation remains challenging, particularly for multi-element systems where the constituent materials differ in their physical properties.
Two complementary strategies for compositional tuning are explored: controlling the whole-particle composition through electrode configuration, and modifying the surface composition through carrier gas selection and in-flight thermal treatment. To resolve the complex dynamics governing both routes, aerosol-based synthesis is combined with advanced characterisation techniques, including electron microscopy, X-ray spectroscopy, and time-resolved in-flight diagnostics.
For whole-particle composition, the results show that AgAu and PdCu nanoparticles closely replicate the electrode composition, with narrow particle-to-particle variation. In contrast, CuZn nanoparticles exhibit a pronounced time-dependent compositional evolution: particles produced during the first minutes of sparking deviate substantially from the electrode composition, but gradually stabilise as the system reaches steady state. Time-resolved measurements using optical emission spectroscopy, inductively coupled plasma mass spectrometry, and in-flight X-ray photoelectron spectroscopy reveal that this behaviour originates during particle generation and is governed by differences in vapour pressure and ablation dynamics between the constituent elements.
For surface composition, in-flight X-ray photoelectron spectroscopy demonstrates that the oxidation state of metal oxide nanoparticles (Sn, Al, Zn) can be modified by adjusting the carrier gas and applying thermal treatment during transport. The degree of surface control is strongly material-dependent, highlighting the need for material-specific optimisation strategies.
Overall, this work demonstrates that compositional control during spark ablation is achievable but material-dependent, and that assumptions regarding the absence of distillation effects do not universally hold. By identifying strategies for tuning both whole-particle and surface composition, these findings support the design of nanoparticles with predictable properties for energy and catalytic applications. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/6fc10384-50bf-45c6-b495-05510b020426
- author
- Jönsson, Linnéa LU
- supervisor
-
- Maria Messing LU
- Calle Preger LU
- Thomas Krinke LU
- Lars Reine Wallenberg LU
- opponent
-
- Prof. Haisch, Cristoph, TU Munich, Germany.
- organization
- publishing date
- 2026
- type
- Thesis
- publication status
- published
- subject
- keywords
- Nanoparticles, composition, Bimetallic, spark ablation, aerosol generation, in-flight, characterization, AgAu, PdCu, CuZn, Metal oxides
- pages
- 76 pages
- publisher
- Department of Physics, Lund University
- defense location
- Lecture Hall Rydbergsalen, Department of Physics, Professorsgatan 1, Faculty of Engineering LTH, Lund University, Lund.
- defense date
- 2026-06-05 09:15:00
- ISBN
- 978-91-90202-13-5
- 978-91-90202-12-8
- project
- Composition of CuZn nanoparticles
- language
- English
- LU publication?
- yes
- id
- 6fc10384-50bf-45c6-b495-05510b020426
- date added to LUP
- 2026-05-07 10:10:00
- date last changed
- 2026-05-07 16:12:08
@phdthesis{6fc10384-50bf-45c6-b495-05510b020426,
abstract = {{Nanoparticle properties depend strongly on composition, making precise control essential for applications in catalysis, sensing, and electronics. By combining two or more elements in a single particle, synergistic properties can emerge that are inaccessible to the individual constituents. Realising these benefits, however, requires reliable methods for tuning composition at the nanoscale.<br/>This thesis investigates how the composition of nanoparticles generated by spark ablation can be controlled. Spark ablation is a continuous gas-phase synthesis method that produces particles with relatively clean, chemical-free surfaces, from virtually any conductive material. Despite its versatility, achieving predictable compositional control during spark ablation remains challenging, particularly for multi-element systems where the constituent materials differ in their physical properties.<br/>Two complementary strategies for compositional tuning are explored: controlling the whole-particle composition through electrode configuration, and modifying the surface composition through carrier gas selection and in-flight thermal treatment. To resolve the complex dynamics governing both routes, aerosol-based synthesis is combined with advanced characterisation techniques, including electron microscopy, X-ray spectroscopy, and time-resolved in-flight diagnostics.<br/>For whole-particle composition, the results show that AgAu and PdCu nanoparticles closely replicate the electrode composition, with narrow particle-to-particle variation. In contrast, CuZn nanoparticles exhibit a pronounced time-dependent compositional evolution: particles produced during the first minutes of sparking deviate substantially from the electrode composition, but gradually stabilise as the system reaches steady state. Time-resolved measurements using optical emission spectroscopy, inductively coupled plasma mass spectrometry, and in-flight X-ray photoelectron spectroscopy reveal that this behaviour originates during particle generation and is governed by differences in vapour pressure and ablation dynamics between the constituent elements.<br/>For surface composition, in-flight X-ray photoelectron spectroscopy demonstrates that the oxidation state of metal oxide nanoparticles (Sn, Al, Zn) can be modified by adjusting the carrier gas and applying thermal treatment during transport. The degree of surface control is strongly material-dependent, highlighting the need for material-specific optimisation strategies.<br/>Overall, this work demonstrates that compositional control during spark ablation is achievable but material-dependent, and that assumptions regarding the absence of distillation effects do not universally hold. By identifying strategies for tuning both whole-particle and surface composition, these findings support the design of nanoparticles with predictable properties for energy and catalytic applications.}},
author = {{Jönsson, Linnéa}},
isbn = {{978-91-90202-13-5}},
keywords = {{Nanoparticles; composition; Bimetallic; spark ablation; aerosol generation; in-flight; characterization; AgAu; PdCu; CuZn; Metal oxides}},
language = {{eng}},
publisher = {{Department of Physics, Lund University}},
school = {{Lund University}},
title = {{From sparks to nanoparticles: controlling composition at the nanoscale}},
url = {{https://lup.lub.lu.se/search/files/249475429/Linn_a_J_nsson_-_WEBB.pdf}},
year = {{2026}},
}