Sustainable nanoparticle production
The spark ablation process used in the VSParticle G1 is a purely physical process that only requires electricity, a carrier gas and electrode material to produce clean nanoparticles. No additional chemicals are required for the production or to stabilize the particles in the aerosol. The produced nanoparticles can be directly incorporated into the next process step or applied in a product by, for example, impaction, electrostatic precipitation or filtering. This way the unique physical properties of the nanoparticles are directly available in the product. The carrier gas can simply be recycled by passing it through a filter and used again, minimizing the environmental impact of the process.
Spark ablation is a gas phase process for the continuous production of very small particles, that can be switched on and off at the touch of a button. The inputs of the process are a conductive feedstock (e.g. Ag or Cu rod), electricity, and a carrier gas. The output is a highly concentrated aerosol of pure (metal) nanoparticles suspended in a clean gas at low temperature (<50°C). With inert carrier gases such as Ar and N2, pure metal nanoparticles are produced with surfaces free from (organic) contaminants. By generating nanoparticles on demand, VSParticle allow you to incorporate nanoparticles directly into your end product without worrying about handling, storage and stability (oxidation). Because no waste streams are produced, spark ablation is uniquely suitable for integration into (existing) production processes.
Wide variety of supported materials
Spark ablation is a versatile technology that works with a wide variety of materials, including metals (e.g. silver, copper, gold, platinum, tungsten or nickel), semiconductors (e.g. silicon) and carbon. The VSParticle G1 has two electrodes, so that nano mixtures of two (previously immiscible) materials are easily accessible as well.
Particle growth is determined by a physical process that allows the mean size of the nanoparticles to be controlled from several atoms to tens of nanometers, by modifying flow and energy input in an intuitive manner. Due to the high temperature in the spark (>20.000K), there is no practical limit to the materials that can be processed. In the most basic form, the material is an elemental metal. Examples of processable elemental materials include noble and common metals, but also Ga (low melting point), W (high melting point), Si (semiconductor), C, Mg (oxidation sensitive). Elemental mixtures are also possible, both for alloying and non-alloying materials.
Review of Spark Discharge Generators for Production of Nanoparticle Aerosols
Meuller, B. O. et al., Aerosol Science and Technology (2012), doi: 10.1080/02786826.2012.705448
Review paper focusing on different implementations of spark generators
New developments in spark production of nanoparticles
Pfeiffer, T. V. et al., Advanced Powder Technology (2014), doi: 10.1016/j.apt.2013.12.005
Review covering size control, scale-up and particle composition/mixing.
Aerosol science & technology
Enormous Enhancement of van der Waals Forces between Small Silver Particles
Burtscher, H., & Schmidt-Ott, A., Physical Review Letters (1982), doi: 10.1103/PhysRevLett.48.1734
Use of spark generated nanoparticles in studying coagulation of very small particles in a gas, indicating a 104 enhancement of dispersion forces in silver.
The transition from spark to arc discharge and its implications with respect to nanoparticle production
Hontañón, E. et al., Journal of Nanoparticle Research (2013), doi: 10.1007/s11051-013-1957-y
Scale-up considerations and the relation of spark discharge to other plasma based aerosol methods.
Aerosol generation by spark discharge
Schwyn, S. et al., Journal of Aerosol Science (1988), doi: 10.1016/0021-8502(88)90215-7
Original description of aerosol particle generator for production of <10nm aerosols of carbon and gold.
Atomic Cluster Generation with an Atmospheric Pressure Spark Discharge Generator
Maisser, A. et al., Aerosol Science and Technology (2015), doi: 10.1080/02786826.2015.1080812
Production of clusters comprising <25 silver atoms.
Precursor-Less Coating of Nanoparticles in the Gas Phase
Pfeiffer, T. V. et al., Materials (2015), doi: 10.3390/ma8031027
Applying metal coatings on nanoparticle aerosols by spark ablation.
Generation of nanoparticles by spark discharge
Tabrizi, N. S. et al., Journal of Nanoparticle Research (2009), doi: 10.1007/s11051-008-9407-y
General guidelines on spark operating conditions.
Reduced Enthalpy of Metal Hydride Formation for Mg–Ti Nanocomposites Produced by Spark Discharge Generation
Anastasopol, A. et al., Journal of the American Chemical Society (2013), doi: 10.1021/ja3123416
Two immiscible metals combined in individual nanoparticles; a metastable alloy of magnesium and titanium reduces the operating temperature in hydrogen storage.
Fractal disperse hydrogen sorption kinetics in spark discharge generated Mg/NbOx and Mg/Pd nanocomposites
Anastasopol, A. et al., Applied Physics Letters (2011), doi: 10.1063/1.3659315
Agglomerates of magnesium nanoparticles and niobium oxide or palladium catalyst particles as a hydrogen storage material.
Spark generation of monometallic and bimetallic aerosol nanoparticles
Byeon, J. H. et al., Journal of Aerosol Science (2008), doi: 10.1016/j.jaerosci.2008.05.006
Production and characterization of monometallic (palladium (Pd), platinum (Pt), gold (Au), and silver (Ag) from electrodes of the same material) and bimetallic (Pd-Pt, Pd-Au, and Pd-Ag from electrodes of different materials) aerosol particles produced by spark discharge.
Characterization of Tungsten Oxide Thin Films Produced by Spark Ablation for NO2 Gas Sensing
Isaac, N. et al., ACS Applied Materials & Interfaces (2016), doi: 10.1021/acsami.5b11078
Tungsten oxide (WOx) thin films used as chemosensor for NO2 sensing.
Optical hydrogen sensing with nanoparticulate Pd–Au films produced by spark ablation
Isaac, N. A. et al., Sensors and Actuators B: Chemical (2015), doi: 10.1016/j.snb.2015.05.095
Optical H2 gas sensing with thin nanoparticulate films Pd–Au (88–12 at.%).
Charge Dependent Catalytic Activity of Gasborne Nanoparticles
Peineke, C. et al., Journal of Nanoscience and Nanotechnology (2011), doi: 10.1166/jnn.2011.4761
Catalytic activity measurements on spark generated aerosols.
Generation of mixed metallic nanoparticles from immiscible metals by spark discharge
Tabrizi, N. S. et al., Journal of Nanoparticle Research (2010), doi: 10.1007/s11051-009-9603-4
Intra-particle mixing of macroscopically immiscible metals. Ag-Cu, Au-Pt and Cu-W.
Synthesis of mixed metallic nanoparticles by spark discharge
Tabrizi, N. S. et al., Journal of Nanoparticle Research (2008), doi: 10.1007/s11051-008-9568-8
Intra-particle mixing using alloyed electrodes, or two different electrodes.
Silicon nanoparticles produced by spark discharge
Vons, V. et al., Journal of Nanoparticle Research (2011), doi: 10.1007/s11051-011-0466-0
Spark discharge with semiconductors. Production of pyrophoric silicon nanoparticles with primary particle size of 3–5 from pristine and doped silicon rods.
Production of carbonaceous nanostructures from a silver-carbon ambient spark
Byeon, J. H., & Kim, J.-W., Applied Physics Letters (2010), doi: 10.1063/1.3396188
Various carbon nanostructures (fibres/tubes/shells/particles) of carbon and silver produced using a carbon and a silver rod.