Aerosol-based Nanotechnology

Apart from their importance in atmospheric chemistry and climate, aerosol particles can be employed in a number of technological applications. Similar to the processes that produce aerosol particle in the atmosphere, we can synthesize particles of a wide range of sizes and chemical compositions in the laboratory. These particles can then be employed for the fabrication of nanostructured materials for application in environmental remediation, energy conversion, catalysis, etc.. One application that our group focuses on is the development of solid-state gas sensors using aerosol-based techniques as described in the paragraphs below.  

Synthesis of Nanoparticles in the Gas Phase

Advances in aerosol technology over the past 30 years have provided methods that enable the synthesis of nanosize building blocks, thereby opening up new opportunities in the assembly of nanostructured materials and nanodevices. These methods can be classified in two categories:

  1. 1.vaporization-condensation (e.g., using furnaces, glowing wires or spark discharges), and

  2. 2.atomization (e.g. using mechanical sprays or electrosprays)

Compared to traditional wet-chemistry techniques, aerosol methods offer a number of advantages including high purity and variability in terms of particle size, morphology and chemical composition.  

Fabrication of Nanomaterials for Solid-state Gas Sensors

Nanoparticle building blocks of well-defined size and composition synthesized in the gas phase (as described above) can be employed to synthesize nanostructured materials for various application, including for use in solid-state gas sensors. Recently we have managed to synthesize a H2 sensor using Pd nanoparticles as shown in Fig. 4. Ongoing research in this direction aims to produce high-sensitivity and selectivity gas sensors for a number of gaseous species (e.g., NOx, SO2, and CO).

Figure 4. Schematic diagram of the experimental setup for fabricating solid-state gas sensors using aerosol nanoparticldes synthesized in the gas phase. Aerosol nanoparticles are generated by a glowing-wire generator. The particles are then passed through an aerosol lens that focuses the particles to a narrow beam before deposition onto the sensor chip. Depending on the number of stages employed in the aerosol lens, the particles can be focused in narrow or wide lenses resulting into deposition of smaller and higher porosities, respectively.

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