Photochemical Reduction of Silver and Tetrachloroaurate Ions on the Surface of Nanostructured Sn3O4 Under the Influence of Visible Light

Abstract

The double tin oxide Sn 3 O 4 with plate morphology was obtained. It was found that such semiconducting materials are photochemically active under the influence of visible light with l > 435 nm in the photoreduction of silver ions and tetrachloroaurate to the respective metals by water with the formation of composite nanostructures. It was shown that the rate of photoreduction of silver ions to metal is substantially lower in the absence of air due, possibly, to photodegradation of the semiconductor.In the last few decades nanostructured particles of semiconductors have aroused interest in connection with their possible use in a whole series of oxidation-reduction photocatalytic processes: release of hydrogen from water, reduction of carbon dioxide, reduction of metal ions, photopolymerization, oxidation of contaminants in water or air, etc.[1]. Among the disadvantages of such materials it is possible to mention their low sensitivity to visible light, which makes it possible to use only a small part of the energy of sunlight. At the same time materials sensitive to visible light very often have clearly defined toxicity (CdS, CdSe, PbS), which significantly limits their widespread use. An urgent task in this connection is the search for and investigation of new nontoxic semiconducting materials that are sensitive to visible light. One such substance is the double tin oxide Sn 3 O 4 , which according to [2,3] can exhibit photocatalytic activity in the decomposition of water and methylene orange under the influence of light with l > 400 nm.In the present work we investigated the photocatalytic activity of the double tin oxide under the influence of visible light with l > 435 nm in the reduction of silver and tetrachloroaurate ions to the respective metals. The photoreduction of the metals was chosen, on the one hand, as a model process for studying the photocatalytic properties of double tin oxide under the influence of visible light. On the other, the metal-semiconducting nanocomposites formed during the reaction can have unusual photo-and electrophysical characteristics [4,5] and can also exhibit enhanced photocatalytic activity in reduction processes 0040-5760/15/5103-0177