Hopcalite is a mixture of copper and manganese oxides used as catalyst to convert carbon monoxide into carbon dioxide when exposed to the oxygen in air. A variety of composition for are known, "Hopcalite II" is approximately 3:1 manganese dioxide : copper oxide. Hopcalite I is a mixture of 50% MnO, 30% CuO, 15% "Co2O3", and 5% Ag2O.
Preparation and applications
Typically these materials are prepared by calcining intimate mixtures of oxides and carbonates. Nanophase catalysts have also been described.
Although primarily used to catalyse the conversion of carbon monoxide to carbon dioxide, Hopcalite catalysts are also used to remove ethylene oxide and other VOCs as well as ozone from gas streams. Hopcalite-type mixtures are used in air filtrations systems for purify breathing air supplies, for example those utilised in scuba diving, and firefighting. Hopcalite is also used as the main filtration ingredient in the self rescue respirators issued to miners. Carbon Monoxide is not removed by activated charcoal air filters.