Photostimulated exoemission and the reduction of copper oxide

A thermal reduction of CuO in a vacuum and a photochemical reduction of CuO were investigated by the photostimulated exoemission (PSE) technique. It w as found that both the chemical reduction and photoexcitation of levels inv olved in charge transfer occur with the transfer of electrons from the envi ronment (ligands) onto an orbital predominantly localized on the metal ion. The exoemission technique is highly sensitive and, unlike the methods of f ormal kinetics, can provide information on the mechanism of the reduction o f oxides at the molecular level. On the basis of the excitation spectra and kinetics and temperature dependence of PSE, a plausible mechanism of elect ronic and ionic processes of the reduction was proposed. The temperatures o f reduction of the oxides measured by the exoemission technique were compar ed with the temperatures of their chemical reduction.