A catalyst is a chemical that causes or speeds up chemical reactions without the catalyst itself changing. A catalyst can speed up the burning of organic gases or require lower temperatures to save fuel usage and reduce costs. Platinum or palladium are two elements often used as catalysts. Automobile catalytic converters operate on the same principles to reduce tailpipe emissions.
One concern with catalytic oxidizers is contamination or deactivation of the catalyst material. Particulate matter like soot and dust can coat the catalyst surface. Certain chemicals can combine or react with the catalyst to deactivate it. Sulfur in gasoline for example, reduces the longevity of auto catalytic converters. The U.S. EPA is pushing for reduced amounts of sulfur in gasoline and diesel fuel. This will reduce the 'poisoning' of catalytic converters for better emission controls and reduced sulfur oxides in the air.