The Composite TiO₂–CuO_x Layers Formed by Electrophoretic Method for CO₂ Gas Photoreduction

Abstract

This study demonstrates the ability to control the properties of TiO2–CuOx composite layers for photocatalytic applications by using a simple electrophoretic deposition method from isopropanol-based suspension. To obtain uniform layers with a controlled composition, the surfactant sodium lauryl sulfate was used, which influenced the electrophoretic mobility of the particles and the morphology of the deposited layers. The TiO2–CuOx composite layers with different CuOx contents (1.5, 5.5, and 11 wt.%) were obtained. It is shown that the optical band gap measured by UV–VIS–NIR diffuse reflectance spectra. When CuOx is added to TiO2, two absorption edges corresponding to TiO2 and CuOx are observed, indicating a broadening of the photosensitivity range of the material relative to pure TiO2. An open-circuit potential study shows that by changing the amount of CuOx in the composite material, one can control the ratio of free charge carriers (n and p) and, therefore, the catalytic properties of the material. As a result, the TiO2–CuOx composite layers have enhanced photocatalytic activity compared to the pure TiO2 layer: methanol yield grows with increasing CuOx content during CO2 photoreduction.

Keywords

• electrophoretic deposition
• TiO₂–CuO_x composites
• photocatalysis
• CO₂ photoreduction