Production of Co, Ni, and Cu nanoparticles by hydrogen reduction

Dissertation

Johanna Forsman

Research output: ThesisDissertationCollection of Articles

Abstract

In this thesis, production of Co, Ni, and Cu nanoparticles by hydrogen reduction of metal chlorides in gas phase was studied. Nanoparticles have unique properties not found in bulk or micron-scale materials. These enable new products or reduced use of raw materials. Metal nanoparticle production has been studied widely, but especially for coated metal particles, research of coating mechanisms and economic production methods is still needed. The method used in this thesis combines a high yield, a high production rate, low production costs, high particle quality, and a good range of available particle number average diameters and other properties. These particles could be utilised in conductive inks, antenna substrates, medical imaging, or as sensors and catalysts. The number average primary particle diameter (NAD) of Co particles increased from 20 to 84 nm as the particle mass concentration increased from 0.5 to 10 g/m3. For even higher particle mass concentrations, the NAD did not increase. The Co and Cu particles were coated in-situ with carbon, by adding ethene to the reaction flow. Copper particles were also coated with carbon and carbon nanotube-like structures by adding ethene and water to the reaction flow. When ethene concentration was increased from zero to 9.2 mol-%, the NAD decreased from 84 to 17 nm for cobalt. Particle mass concentration was 10 g/m3 or higher in these experiments. The standard deviation was 17 nm when NAD 84 nm and 7 nm when NAD was 17 nm. For copper, the NAD increased from 20 to121 nm. The particles were crystalline with an FCC structure in all cases. The particle growth was modelled in a simplified way. It appears, that surface reaction is an important part of the particle growth process. The most likely scenario is that first, seed particles form by gas phase reaction and nucleation. Then, these particles grow partly by surface reaction and partly by condensation growth. In the gas phase, some backward reaction of metal to metal chloride occurs. The saturation magnetic moment of the Co and Co+C particles was 141-147 emu/g, which is close to bulk Co (159 emu/g). No hysteresis was observed for these particles. Cobalt particles with and without carbon coating were used to fabricate polymer composites, which could be applied in RF antennae. The relative permeability of the composite was increased from 1 to 3 as the loading of the particles increased from zero to 28 vol-%. Copper particles coated with carbon coating and CNT-like structures were used to fabricate inkjet fluid capable of producing conductive lines after printing a single layer. The best achieved conductivity was 6.4 S/m.
Original languageEnglish
QualificationDoctor Degree
Awarding Institution
  • Aalto University
Supervisors/Advisors
  • Kauppinen, Esko, Supervisor, External person
  • Jokiniemi, Jorma, Advisor, External person
Award date27 Aug 2013
Place of PublicationEspoo
Publisher
Print ISBNs978-951-38-8007-1
Electronic ISBNs978-951-38-8008-8
Publication statusPublished - 2013
MoE publication typeG5 Doctoral dissertation (article)

Fingerprint

NAD
Hydrogen
Nanoparticles
Carbon
Metals
Copper
Gases
Surface reactions
Cobalt
Coatings
Chlorides
Antennas
Carbon Nanotubes
Metal nanoparticles
Medical imaging
Composite materials
Magnetic moments
Ink
Seed
Hysteresis

Keywords

  • cobalt
  • copper
  • nickel
  • nanoparticles
  • core-shell
  • magnetic nanoparticle

Cite this

Forsman, J. (2013). Production of Co, Ni, and Cu nanoparticles by hydrogen reduction: Dissertation. Espoo: VTT Technical Research Centre of Finland.
Forsman, Johanna. / Production of Co, Ni, and Cu nanoparticles by hydrogen reduction : Dissertation. Espoo : VTT Technical Research Centre of Finland, 2013. 70 p.
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abstract = "In this thesis, production of Co, Ni, and Cu nanoparticles by hydrogen reduction of metal chlorides in gas phase was studied. Nanoparticles have unique properties not found in bulk or micron-scale materials. These enable new products or reduced use of raw materials. Metal nanoparticle production has been studied widely, but especially for coated metal particles, research of coating mechanisms and economic production methods is still needed. The method used in this thesis combines a high yield, a high production rate, low production costs, high particle quality, and a good range of available particle number average diameters and other properties. These particles could be utilised in conductive inks, antenna substrates, medical imaging, or as sensors and catalysts. The number average primary particle diameter (NAD) of Co particles increased from 20 to 84 nm as the particle mass concentration increased from 0.5 to 10 g/m3. For even higher particle mass concentrations, the NAD did not increase. The Co and Cu particles were coated in-situ with carbon, by adding ethene to the reaction flow. Copper particles were also coated with carbon and carbon nanotube-like structures by adding ethene and water to the reaction flow. When ethene concentration was increased from zero to 9.2 mol-{\%}, the NAD decreased from 84 to 17 nm for cobalt. Particle mass concentration was 10 g/m3 or higher in these experiments. The standard deviation was 17 nm when NAD 84 nm and 7 nm when NAD was 17 nm. For copper, the NAD increased from 20 to121 nm. The particles were crystalline with an FCC structure in all cases. The particle growth was modelled in a simplified way. It appears, that surface reaction is an important part of the particle growth process. The most likely scenario is that first, seed particles form by gas phase reaction and nucleation. Then, these particles grow partly by surface reaction and partly by condensation growth. In the gas phase, some backward reaction of metal to metal chloride occurs. The saturation magnetic moment of the Co and Co+C particles was 141-147 emu/g, which is close to bulk Co (159 emu/g). No hysteresis was observed for these particles. Cobalt particles with and without carbon coating were used to fabricate polymer composites, which could be applied in RF antennae. The relative permeability of the composite was increased from 1 to 3 as the loading of the particles increased from zero to 28 vol-{\%}. Copper particles coated with carbon coating and CNT-like structures were used to fabricate inkjet fluid capable of producing conductive lines after printing a single layer. The best achieved conductivity was 6.4 S/m.",
keywords = "cobalt, copper, nickel, nanoparticles, core-shell, magnetic nanoparticle",
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note = "Project code: 50010",
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Forsman, J 2013, 'Production of Co, Ni, and Cu nanoparticles by hydrogen reduction: Dissertation', Doctor Degree, Aalto University, Espoo.

Production of Co, Ni, and Cu nanoparticles by hydrogen reduction : Dissertation. / Forsman, Johanna.

Espoo : VTT Technical Research Centre of Finland, 2013. 70 p.

Research output: ThesisDissertationCollection of Articles

TY - THES

T1 - Production of Co, Ni, and Cu nanoparticles by hydrogen reduction

T2 - Dissertation

AU - Forsman, Johanna

N1 - Project code: 50010

PY - 2013

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N2 - In this thesis, production of Co, Ni, and Cu nanoparticles by hydrogen reduction of metal chlorides in gas phase was studied. Nanoparticles have unique properties not found in bulk or micron-scale materials. These enable new products or reduced use of raw materials. Metal nanoparticle production has been studied widely, but especially for coated metal particles, research of coating mechanisms and economic production methods is still needed. The method used in this thesis combines a high yield, a high production rate, low production costs, high particle quality, and a good range of available particle number average diameters and other properties. These particles could be utilised in conductive inks, antenna substrates, medical imaging, or as sensors and catalysts. The number average primary particle diameter (NAD) of Co particles increased from 20 to 84 nm as the particle mass concentration increased from 0.5 to 10 g/m3. For even higher particle mass concentrations, the NAD did not increase. The Co and Cu particles were coated in-situ with carbon, by adding ethene to the reaction flow. Copper particles were also coated with carbon and carbon nanotube-like structures by adding ethene and water to the reaction flow. When ethene concentration was increased from zero to 9.2 mol-%, the NAD decreased from 84 to 17 nm for cobalt. Particle mass concentration was 10 g/m3 or higher in these experiments. The standard deviation was 17 nm when NAD 84 nm and 7 nm when NAD was 17 nm. For copper, the NAD increased from 20 to121 nm. The particles were crystalline with an FCC structure in all cases. The particle growth was modelled in a simplified way. It appears, that surface reaction is an important part of the particle growth process. The most likely scenario is that first, seed particles form by gas phase reaction and nucleation. Then, these particles grow partly by surface reaction and partly by condensation growth. In the gas phase, some backward reaction of metal to metal chloride occurs. The saturation magnetic moment of the Co and Co+C particles was 141-147 emu/g, which is close to bulk Co (159 emu/g). No hysteresis was observed for these particles. Cobalt particles with and without carbon coating were used to fabricate polymer composites, which could be applied in RF antennae. The relative permeability of the composite was increased from 1 to 3 as the loading of the particles increased from zero to 28 vol-%. Copper particles coated with carbon coating and CNT-like structures were used to fabricate inkjet fluid capable of producing conductive lines after printing a single layer. The best achieved conductivity was 6.4 S/m.

AB - In this thesis, production of Co, Ni, and Cu nanoparticles by hydrogen reduction of metal chlorides in gas phase was studied. Nanoparticles have unique properties not found in bulk or micron-scale materials. These enable new products or reduced use of raw materials. Metal nanoparticle production has been studied widely, but especially for coated metal particles, research of coating mechanisms and economic production methods is still needed. The method used in this thesis combines a high yield, a high production rate, low production costs, high particle quality, and a good range of available particle number average diameters and other properties. These particles could be utilised in conductive inks, antenna substrates, medical imaging, or as sensors and catalysts. The number average primary particle diameter (NAD) of Co particles increased from 20 to 84 nm as the particle mass concentration increased from 0.5 to 10 g/m3. For even higher particle mass concentrations, the NAD did not increase. The Co and Cu particles were coated in-situ with carbon, by adding ethene to the reaction flow. Copper particles were also coated with carbon and carbon nanotube-like structures by adding ethene and water to the reaction flow. When ethene concentration was increased from zero to 9.2 mol-%, the NAD decreased from 84 to 17 nm for cobalt. Particle mass concentration was 10 g/m3 or higher in these experiments. The standard deviation was 17 nm when NAD 84 nm and 7 nm when NAD was 17 nm. For copper, the NAD increased from 20 to121 nm. The particles were crystalline with an FCC structure in all cases. The particle growth was modelled in a simplified way. It appears, that surface reaction is an important part of the particle growth process. The most likely scenario is that first, seed particles form by gas phase reaction and nucleation. Then, these particles grow partly by surface reaction and partly by condensation growth. In the gas phase, some backward reaction of metal to metal chloride occurs. The saturation magnetic moment of the Co and Co+C particles was 141-147 emu/g, which is close to bulk Co (159 emu/g). No hysteresis was observed for these particles. Cobalt particles with and without carbon coating were used to fabricate polymer composites, which could be applied in RF antennae. The relative permeability of the composite was increased from 1 to 3 as the loading of the particles increased from zero to 28 vol-%. Copper particles coated with carbon coating and CNT-like structures were used to fabricate inkjet fluid capable of producing conductive lines after printing a single layer. The best achieved conductivity was 6.4 S/m.

KW - cobalt

KW - copper

KW - nickel

KW - nanoparticles

KW - core-shell

KW - magnetic nanoparticle

M3 - Dissertation

SN - 978-951-38-8007-1

T3 - VTT Science

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Forsman J. Production of Co, Ni, and Cu nanoparticles by hydrogen reduction: Dissertation. Espoo: VTT Technical Research Centre of Finland, 2013. 70 p.