Reactivity of SnO sub 2 -CuO nanocrystalline materials with H sub 2 S: a coupled electrical and Raman spectroscopic study

Nanocrystalline CuO-doped SnO sub 2 powders produced by different ways have been subjected to H sub 2 S at 100C. As for pure SnO sub 2 , the reversible formation of SnS sub x was deduced from Raman spectra and correlated with the changes in electrical resistance. When the initial resistance of the sample was high, adsorbed SO sub 4 was observed, and in this case only, the reversible formation of Cu sub 2 S. These various phenomena are discussed in the light of thermodynamic data and the influence of powder preparation is emphasized.