Broadening the Action Spectrum of TiO(2)-Based Photocatalysts to Visible Region by Substituting Platinum with Copper

In this study, TiO(2)-based photocatalysts modified with Pt and Cu/CuO(x) were synthesized and studied in the photocatalytic reduction of CO(2). The morphology and chemical states of synthesized photocatalysts were studied using UV-Vis diffuse reflectance spectroscopy, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy. A series of light-emitting diodes (LEDs) with maximum intensity in the range of 365–450 nm was used to determine the action spectrum of photocatalysts. It is shown for, the first time, that the pre-calcination of TiO(2) at 700 °C and the use of Cu/CuO(x) instead of Pt allow one to design a highly efficient photocatalyst for CO(2) transformation shifting the working range to the visible light (425 nm). Cu/CuO(x)/TiO(2) (calcined at 700 °C) shows a rate of CH(4) formation of 1.2 ± 0.1 µmol h(−1) g(−1) and an overall CO(2) reduction rate of 11 ± 1 µmol h(−1) g(−1) (at 425 nm).