Corona discharge reactor

A corona discharge reactor for use in the processing of gaseous materials, comprising a reactor chamber through which a gaseous medium to be processed can be caused to flow, a first electrode within the chamber comprising an axially extending rod at least a portion of which has an effective plurality of radially extending projections, and a second electrode within the chamber surrounding that portion of the first electrode which has the effective plurality of radially extending projections, the surfaces of the said electrodes being exposed directly to each other, and the second electrode being fixed relative to the first electrode, electrically insulated and spaced apart therefrom, wherein to provide between the said first and second electrodes a path for flow of the said gaseous medium through the reactor chamber and wherein to support a corona discharge when an electric potential is applied across the electrodes.