Abstract: A spray pyrolysis method for producing pure metal and/or metal oxide particles uses a mixture of a carrier gas and a solution of a metal salt precursor, water and a co-solvent reducing agent. The metal salt precursors preferably comprise metals from the group consisting of Fe, Co, Ni, Cu, Zn, Pd, Ag and Au, whereas the salt anions preferably comprise nitrates, acetates, oxalates and chlorides. The co-solvents are those that act as a reducing agent, are vaporizable, are inert with respect to the carrier gas, and are hydrophilic, such as alcohols, in particular, low-carbon numbered alcohols such as methanol or ethanol.