A method of making composite nanoscale particles comprising subjecting a starting material to laser energy so as to form a vapor and condensing the vapor so as to form the composite nanoscale particles, wherein said composite nanoscale particles comprise a first metal and/or a first metal oxide incorporated in nanoscale particles of an oxide of a second metal, the first metal being different than the second metal. The starting material can comprise first and second metals or compounds of the first and second metals. The composite nanoscale particles can be formed in a reaction chamber wherein a temperature gradient is provided. The atmosphere in the chamber can be an inert atmosphere comprising argon or a reactive atmosphere comprising oxygen. The composite nanoscale particles are useful for low-temperature and near-ambient temperature catalysis. The composite nanoscale particles can be incorporated in the tobacco cut filler, cigarette paper and/or cigarette filter material of a cigarette to catalyze the oxidation of carbon monoxide to carbon dixoxide.