Dynamic of the plasma current amplitude in a barrier discharge: influence of photocatalytic material

For a better understanding of the plasma/photocatalytic material interaction under plasma exposure, a study of the electrical properties of a cylindrical sinusoidal dielectric barrier discharge is performed with and without porous material containing TiO2. The metallic inner electrode is in contact with the gas gap. First, the presence of porous material made of silica fibres coated with nanoparticles of TiO2 leads to a strong increase of the injected energy for the same applied voltage. Then the time evolution of the current amplitude distribution function (CADF) shows two different peak populations on the positive half period (when the metallic inner electrode is positive). Apart from numerous low intensity plasma filaments (around 1mA amplitude), much larger ones exist (around 1 A). These large current amplitude peaks are responsible for 50-70% of the injected energy depending on the presence of the photocatalytic material. The influence of 900 ppm of C2H2 as well as external ultraviolet irradiation on the CADF is also reported.