Abstract: A method of preparing polycrystalline photoactive semiconductor electrodes utilizable in photoassisted oxidation reactions comprises the steps of (1) providing a suspension of finely divided mixture of titanium dioxide and at least one oxide of a metal selected from the group consisting of aluminum and the d-electron transition metals other than titanium, (2) applying the suspension to the surface of a metal body, (3) sintering the applied coating to the metal body.

Abstract: A method of preparing doped or modified polycrystalline p- or n-type titanium dioxide semiconductor electrodes utilizable in photoassisted oxidation reactions or photoelectrochemical cells is provided. The method comprises the steps of (1) applying to a titanium substrate a thin film of one or more oxide of metals selected from the group consisting of aluminum and the d-electron transition metals other than titanium, and (2) heating the coated titanium body in an oxygen-containing atmosphere at an elevated temperature, preferably below about 800.degree. C., to sinter the coating to the titanium substrate. The sintering step produces on the titanium substrate a thin photoactive film of titanium dioxide containing a uniform concentration gradient of the previously-applied modifying oxide.

Abstract: Photoactive titanium dioxide based semiconductor electrodes utilizable in photoassisted oxidation reactions in an electrochemical cell comprise thin films of polycrystalline titanium dioxide modified with one or more materials consisting of oxides of aluminum or of a d-electron transition metal other than titanium. Oxides in which the metal is in a chemical oxidation state other than +4, which possess some solid state solubility in titanium dioxide, and an impurity energy level band lying within the energy band gap of titanium dioxide function effectively as modifiers.The electrode comprises a uniform film of titanium dioxide mixed with up to 50 mole percent of the modifier sintered to a suitable metal body. In an alternative embodiment of the invention, the electrode comprises a film of titanium dioxide sintered to a titanium metal body with the modifier distributed throughout the titanium dioxide film with a concentration gradient having a minimum next to the surface of the metal body.

Abstract: A catalytic process for the reduction to elemental sulfur of the sulfur dioxide contained in gas streams using a reducing gas such as hydrogen, or preferably carbon monoxide, in a reactor charged with a material represented by the general formula M.sup.II M.sub.2.sup. III O.sub.4 crystallized in the spinel structure wherein M.sup.II is a divalent metal and M.sup.III is a trivalent metal from the first transition period of the Periodic Table of the Elements, or derivatives of the materials of the above formula resulting from pretreatment with hydrogen or, preferably carbon monoxide, and/or exposure to the sulfur dioxide-containing gas stream.

Abstract: A photochemical energy storage system includes at least one electrolytic solution containing a reduction-oxidation couple, one species of which can be stored in a second phase. The device includes a charging system and an energy delivery system. The charging system includes an n-or p-type photosensitive electrode at which, under illumination, an oxidation or reduction reaction occurs. In the charging cycle, one species is oxidized while the other is reduced, and one of these products is stored in a phase other than the phase in which the reaction occurs. The energy delivery system transfers electrons to or from the high energy product on demand for delivery through an electrical load to an electrode at which the original reactants can be reconstituted.

Abstract: A photoelectrochemical metal plating and purification process includes at least one electrolyte containing a reduction-oxidation couple, one species of which is a metal cation which can be reduced to elemental metal at an electrode. The system includes an N-type photosensitive semiconductor electrode at which, under illumination, an oxidation reaction occurs, with concurrent reduction of the metal cation at the counter electrode. In operation, one ionic species of the electrolyte is oxidized while metal ions are reduced and collected as the elemental metal at the counter electrode. In cases where the elemental metal is liquid at the operation temperature, it is collected as a liquid metal pool under the counter electrode.