 More than half the supply of palladium and its congener platinum is used in catalytic converters, which convert as much as 90 % of the harmful gases in automobile exhaust (hydrocarbons, carbon monoxide, and nitrogen dioxide) into harmless substances (nitrogen, carbon dioxide and water vapor). Palladium is also used in electronics, dentistry, medicine, hydrogen purification, chemical applications, groundwater treatment, and jewelry. Palladium is a key component of fuel cells, which react hydrogen with oxygen to produce electricity, heat, and water.
