Dielectric Barrier Discharge

It consists of two metal electrodes, in which at least one is coated with a dielectric layer. Plasma gas flows in the gap. The discharge is ignited by means of a sinusoidal or pulsed power source. The gap is on the order of several mm and the plasma is generated through a succession of micro arcs, lasting for 10 – 100 ns and distributed randomly. These systems are used for many applications like surface cleaning, material functionalization, etc.

The conversion of methane and carbon dioxide in a DBD reactor have been tested according to the setup shown in figure 3. The main products are synthesis gas C₂ hydrocarbons and oxygenated hydrocarbons, like methanol or formaldehyde. The reactor (Fig. 3, right) consists of a 15 cm long Duran glass cylinder with an inner diameter of 5.9 mm and an outer diameter of 8.0 mm. The inner working iron electrode with a diameter of 3.0 mm is fixed on the top by two glass frits and on the bottom by glass wool. The outer part of the glass body is covered over a length of 50 mm with a conductive silver varnish to create the outer grounded counter electrode. The outer electrode has over the whole length a slit of about one millimeter width to monitor the plasma. The plasma is generated by a 13.56 MHz radio frequency generator.

Figure 3 The experimental setup (left) and DBD reactor(right) (DOI:  10.1007/s11090-012-9411-y)