Oxidation of nanocrystalline lead sulfide in air

The oxidation of nanocrystalline PbS powders with a particle size of 10–20 nm and the oxidation of ∼100-nm-thick nanocrystalline PbS films with a crystallite size of 70–80 nm have been investigated in the temperature range from 293 to 773 K. The nanocrystalline powders and films were prepared by chemical deposition from aqueous solutions. The nanopowders with a particle size of 10–20 nm begin to oxidize at a 450 K lower temperature than bulk lead sulfide (870 K). The PbS nanofilms are more resistant to oxidation than the nanopowders and are stable in air up to 573 K. The oxidation behavior of the nanopowders and nanofilms is in agreement with the sulfate theory of PbS oxidation.