TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Method: In the method of preparing the cigarette, the step of incorporating comprises spraying, dusting or immersion. The method of preparing the cigarette, further comprises: mixing particles of silver and/or silver oxide with particles of an oxide of a second metal to form the silver-based catalyst, where the particles of silver and/or silver oxide are supported in and/or on the particles of the oxide of the second metal; forming the silver-based catalyst via the precipitation or thermal decomposition of a silver salt; combining the salt with a solvent to form a silver precursor solution; combining the silver precursor solution with a colloidal solution of an oxide of a second metal to form a mixture, where the second metal is different than silver, heating the mixture to thermally decompose the silver salt to form nanoscale particles of silver and/or silver oxide, where the nanoscale particles are incorporated in and/or on the oxide of the second metal; drying the mixture to form the catalyst; heating the catalyst at at least 200 degrees C prior to incorporating the catalyst in and/or on the at least one of tobacco cut filler, cigarette paper and cigarette filter material; forming the catalyst via laser vaporization and controlled condensation of a target material; and heating the catalyst at at least 200 degrees C, in an atmosphere that oxidizes the silver prior to incorporating the catalyst in and/or on the at least one of tobacco cut filler, cigarette paper and cigarette filter material. The precipitation or thermal decomposition of the silver salt forms nanoscale particles of silver and/or silver oxide. The oxide of the second metal is at least partially a non-stoichiometric oxide. The catalyst is heated in an atmosphere that oxidizes the silver to form a catalyst consisting essentially of silver oxide supported in and/or on the oxide of the second metal. The target material comprises silver and a second metal different than silver. The catalyst consists essentially of nanoscale particles of silver and/or silver oxide supported in and/or on an oxide of a second metal, the second metal being different than silver. In the method of preparing the cigarette, at least some of the silver is incorporated on a surface of the oxide of the second metal. The catalyst comprises nanoscale particles of silver and/or silver oxide supported in and/or on nanoscale particles of an oxide of a second metal, the second metal being different than silver. The nanoscale particles of silver and/or silver oxide and the nanoscale particles of an oxide of a second metal condense in the gas phase to form the catalyst. The catalyst is present to convert at least 5% of the carbon monoxide in mainstream smoke drawn through the cigarette to carbon dioxide at less than 210 degrees C. The catalyst is present to reduce the concentration of carbon monoxide and/or reduce the concentration of total particulate matter drawn through the cigarette during smoking. Preferred Components: The catalyst consists essentially of silver and/or silver oxide and the oxide of a second metal. The catalyst comprises nanoscale particles of silver and/or silver oxide and the oxide of a second metal. The particles comprising silver have an average particle size of less than 100 nm or less than 50 nm. The particles comprising silver and/or silver oxide comprise agglomerates of nanoscale particles, where the agglomerates have an average size of 1-50 microns. The agglomerates consist essentially of silver and/or silver oxide. The catalyst comprises particles of silver and/or silver oxide supported in and/or on the support particles. The particles of silver and/or silver oxide are nanoscale particles. The support particles have an average particle size of less than about 500 nm. The second metal is magnesium, aluminum, silicon, titanium, vanadium, chromium, manganese, iron, yttrium, zirconium, niobium, cerium and/or hafnium. The oxide of the second metal is at least partially a non-stoichiometric oxide. The catalyst comprises 1-70 wt.% or 5-20 wt.% of silver and/or silver oxide. The catalyst consists essentially of nanoscale particles of silver and/or silver oxide supported in and/or on nanoscale or micron-sized particles of cerium oxide. The salt is silver nitrate.