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NANOSYSTEMS: PHYSICS, CHEMISTRY, MATHEMATICS, 2020, 11 (5), P. 601–607

Synthesis and comparative photocatalytic activity of CuO layers on SiO₂ substrates

E.V. Polyakov – Institute of Solid State Chemistry UB RAS, 91, Pervomaiskaya str., Ekaterinburg, 620990, Russian Federation; polyakov@ihim.uran.ru
R. R. Tzukanov – Institute of Solid State Chemistry UB RAS, 91, Pervomaiskaya str., Ekaterinburg, 620990, Russian Federation
I.V. Volkov – Institute of Solid State Chemistry UB RAS, 91, Pervomaiskaya str., Ekaterinburg, 620990, Russian Federation
L.Yu. Buldakova – Institute of Solid State Chemistry UB RAS, 91, Pervomaiskaya str., Ekaterinburg, 620990, Russian Federation
I.V. Baklanova – Institute of Solid State Chemistry UB RAS, 91, Pervomaiskaya str., Ekaterinburg, 620990, Russian Federation
O. A. Lipina – Institute of Solid State Chemistry UB RAS, 91, Pervomaiskaya str., Ekaterinburg, 620990, Russian Federation
V. P. Zhukov – Institute of Solid State Chemistry UB RAS, 91, Pervomaiskaya str., Ekaterinburg, 620990, Russian Federation
Yu.V. Kuznetsova – Institute of Solid State Chemistry UB RAS, 91, Pervomaiskaya str., Ekaterinburg, 620990, Russian Federation
A. P. Tutyunnik – Institute of Solid State Chemistry UB RAS, 91, Pervomaiskaya str., Ekaterinburg, 620990, Russian Federation
M. A. Maximova – Institute of Solid State Chemistry UB RAS, 91, Pervomaiskaya str., Ekaterinburg, 620990, Russian Federation

Using the thermodynamic and kinetic approaches, it was found that Cu(NH₃)²⁺_{4 aq} complex predominating at 23 °C spontaneously decomposes at elevated temperatures, forming CuO precipitate in a bulk solution and a layer (CuO||SiO₂) on the surface of silica glass. The rates of these heterogeneous processes are fairly well described by the 1st-order reaction of decay of the Cu(NH₃)²⁺_{4 aq} complex. The formation of the CuO precipitate and layer is a two-step kinetic process. The rate of precipitate formation dominates above 65 °C while the rate of the layer formation prevails below this value. The CuO||SiO₂ material synthesized below 65 possesses an optical bandgap of (1.250.05) eV, which is smaller compared to the crystals of commercial CuO. The CuO||SiO₂ material displays a photocatalytic activity in the reaction of UV-decomposition of benzoquinone-hydroquinone. It was discovered that the photocatalytic activity depends on the thickness of the photocatalyst layer.

Keywords: Copper(II), oxide, layer, glass, surface, kinetics, photocatalyst.

PACS 81.15.-z; 78.20.-e

DOI 10.17586/2220-8054-2020-11-5-601-607

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