Samples of the exhaust gases, taken over mercury, were analysed by the ordinary volumetric methods, the CO₂ being absorbed by potash, the oxygen by pyrogallol, the CO by an acid solution of cuprous chloride, and the hydrogen by palladianized asbestos.
Source: wiktionary
Thus, in the presence of palladianized asbestos at temperatures above 339° C. carbon dioxide and water were formed if sufficient oxygen was present and carbon monoxide and water if the oxygen was not sufficient for the complete combustion.
Source: wiktionary
In the older models, the catalyst (platinized or palladianized asbestos) had to be heated. The use of palladianized alumina pellets, which are active at room temperature, has made this unnecessary (Heller, 1954).
Source: wiktionary