Catalyst retaining apparatus and use in an ozone filter

An ozone removing filter for use in ozone producing apparatus which comprises:

• a porous substrate of expanded polytetrafluoroethylene (PTFE) matrix, the matrix comprising polymeric nodes interconnected by fibrils and the substrate having at least one exposed surface;
• particles of ozone decomposing catalysts interconnected to the nodes and fibrils within the PTFE matrix, the particles being securely held within the matrix so as to resist shedding while being in open fluid communication with the exposed surface of the substrate;
• wherein the substrate is adapted to be installed within the ozone producing apparatus so as to cause an ozone containing gas to pass across the exposed surface of the substrate and to allow the ozone decomposing catalysts to react with the gas to remove ozone therefrom.