Microplasma reactors

A number of configurations of microplasma reactors will be described here. Classification will be based on the power sources, the electric field switching frequency ranging from DC to GHz, and electrode geometries and materials, extending from DBDs to micro hollow cathodes and microcavity discharges. 

Figure 7 Schematic diagram of microplasma reactor for the synthesis of silicon nanoparticles. A microdischarge forms at the cathode tip and extends a short distance toward the anode (Sankaran et al, 2005 reproduced with permission).

Figure 8 Schematic diagram of experimental setup and image of microplasma reactor with VHF source developed for the synthesis of photoluminescent silicon nanocrystals at room temperature (Nozaki et al, 2007a reproduced with permission). M.B. is a matching electrical circuit.

Figure 9 Capillary head of UHF microplasma reactor developed for the synthesis of molybdenum oxide nanoparticles (Bose et at, 2006 reproduced with permission).

Through the generation of highly reactive species such as energetic electrons and active radicals, microplasma reactors create novel process windows for C-C and C-H bond cleavage involved in the decomposition of harmful gaseous pollutants at atmospheric pressure. As an example of... 

Figure 12 Illustration of a surface-discharge microplasma reactor developed for the decomposition of VOCs in the gas phase (Seto et al., 2005 reproduced with permission).

Figure 13 Illustration of a single microplasma reactor and its integration in a multireactor. Numbered features are (1) plasma source, (2) glass structure, (3) reaction chamber, (4) inlet and outlet of the reactor, (5) gas flow, (6) 4 x 4 array in a multireactor, and (7) contact pads for RF power (Sichler et at, 2004 reproduced with permission).

Figure 15 On-chip microplasma reactor using nanostructured electrodes, (a) silicon chip before and after a CVD process for nanostructure growth, (b) microplasma reactor, and (c) general diagram of the device (Agiral et al., 2008b reproduced with permission).

Performing plasma processes in a continuous-flow microreactor leads to precise control of residence time and to extreme quenching conditions, therewith enabling control over the composition of the reaction mixture and product selectivity. In a nonequilibrium microplasma reactor, low-temperature activation of hydrocarbons and fuels, which is difficult to obtain in conventional thermochemical processes, can be achieved at ambient conditions. 

Figure 16 Microplasma reactor setup for partial oxidation of methane (left) and photo of thin glass tube equipped with a twisted metal wire (right) (Nozaki et al., 2007a reproduced with permission).

Figure 18 Microplasma reactor, based on DBD, for oxidative conversion of C,-C3 alkanes A gas inlet B gas outlet C frontside copper electrode D backside electrode (Trionfetti et at, 2008a reproduced with permission).

Figure 19 Photographs of microplasma reactor fabricated by replica molding on a plastic substrate (left) and magnified view of the 10 x 10 array of 400 pm diameter microcavity plasma channels, operating in argon (right) (Anderson et al, 2008 reproduced with permission).

Nozaki, T., Agiral, A., Yuzawa, S., Han Gardeniers, J.G.E., and Okazaki, K. (2011) A single step methane conversion into synthetic fuels using microplasma reactor. Chem. Eng. ]., 166 (1), 288-293. 

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