Synthesis And Comparative Photocatalytic Activity Of Cuo Layers On Sio2 Substrates

Using the thermodynamic and kinetic approaches, it was found that Cu(NH3)(4 aq)(2+) complex predominating at 23 degrees C spontaneously decomposes at elevated temperatures, forming CuO precipitate in a bulk solution and a layer (CuO parallel to 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)(4 aq)(2+) complex. The formation of the CuO precipitate and layer is a two-step kinetic process. The rate of precipitate formation dominates above 65 degrees C while the rate of the layer formation prevails below this value. The CuO parallel to SiO2 material synthesized below 65 degrees possesses an optical bandgap of (1.25 +/- 0.05) eV, which is smaller compared to the crystals of commercial CuO. The CuO parallel to 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.