The invention refers to a capacitor device for generating radicals and oxidants in oxygen-containing gases via non-thermal, plasma-chemical transformation, comprising - a strongly structured, grounded outer electrode (1), - an inner electrode (4), - a dielectric barrier (2) separating the electrodes (1) and (4), and - a connecting electrode connecting the inner electrode (4) to a power supply, wherein the inner electrode (4) consists of a package of conductive fibers and is distributed homogeneously across the dielectric barrier (2). Also, the invention concerns a method for generating radicals and oxidants in oxygen-containing gases via non-thermal, plasma-chemical transformation, comprising applying a smoothed, high-frequency alternating voltage to the electrodes (1) and (4) of the capacitor device of the present invention.