Modular constructed metal-grid arrays—an alternative to silicon-based microplasma devices for catalytic applications

Here, we present a modular constructed metal-grid micro cavity plasma array as a flexible, robust, and simple alternative to micro-structured devices based on silicon. They show great potential for applications requiring large-area treatment, catalytic conversion or decomposition of volatile organic compounds. The metal-grid array is an easily assembled layered structure consisting of a metal grid, a dielectric foil and a magnet. The grid contains between hundreds and thousands of uniformly arranged cavities with a diameter of 150 μ m. The whole system is kept together by magnetic force. This also allows disassembling and exchange of the components independently. Typically, the arrays are operated close to atmospheric pressure with an alternating voltage of up to 1.4 kV peak-to-peak in the kHz range. For a first comparison with silicon-based configurations, the metal-grid array is examined from two different perspectives using phase-resolved imaging. The individual cavities show the same asymmetric discharge behaviour as in the silicon-based arrays. In addition, the expansion width of the discharge from the cavities could be measured. The same interaction between the cavities with the propagation of an ionization wave with velocities in the km/s range is observed as for the silicon-based devices. Thus, with respect to the most basic discharge properties, both configurations show the same behaviour, although they are different in structure and composition.