Briefly,
for the needle-plate reactor the electrode system was immersed in a cylindrical glass vessel
(φ 105x160 mm) with a needle-plate gap 28 mm. The HV tungsten needle anode was almost
totally insulated with a Teflon tube from the surrounding water such that only a small conical tip
of the anode (initial radius of curvature ∼70 µm) was in direct contact with water. The coaxial
reactor consisted of a stainless steel rod anode 6 mm in diameter surrounded by an external
stainless steel tubular cathode of 30 mm in diameter. The 200 mm long anode was covered by a
thin (dc = 0.2 - 0.3 mm) layer of porous ceramic (open porosity 2% - 5%, εrc ∼ 8) deposited
on the rod surface by the technology of plasma spraying (composite anode).