Preparation and characterization of Cu-doped TiO2 materials for electrochemical, photoelectrochemical, and photocatalytic applications

• DOI: 10.1016/j.apsusc.2013.12.140
• Publication Date: 2014-01-04T00:01:18Z
• Authors: Ibram Ganesh; Polkampally P. Kumar; Ibram Annapoorna; Jordan M. Sumliner; Mantripragada Ram...; Neha Y. Hebalkar; Gade Padmanabham; Govindan Sundarar...
• Keywords: 7. Clean energy; 01 natural sciences; 0104 chemical sciences

Abstract The Cu-doped TiO2 (Cu = 0-50 wt.%) powders and thin films were prepared by following a homogeneous co-precipitation method and sol-gel dip-coating technique, respectively, and were treated through 400-800 °C, and then thoroughly investigated by following various characterization techniques. The characterization results suggest that the pure TiO2 powder formed at 550 °C is in rutile phase, whereas the 0.1-10 wt.% Cu-doped TiO2 powders formed at 550 °C are mainly in anatase phase. These latter powders possess low band-gap energies (3.247-3.265 eV) and flat-band potentials amenable to water oxidation reaction. The 0.5-wt.% Cu-doped TiO2 thin film formed at 550 °C exhibited n-type semiconducting behavior and considerable photocurrent among various investigated powders. The CO2 reduction with a Faradaic efficiency of 82% and ∼ 96% CO selectivity in a two-compartment electrochemical cell was noted at −2500 mV (vs. Ag/Ag+) on pre-reduced (at −2000 mV vs. Ag/AgCl) 50 wt.% Cu-doped TiO2 thin film electrode in conjunction with an ionic liquid. The UV-light-induced TiO2 was found to be responsible for photocatalytic methylene blue (MB) degradation, and TiO2 is not sensitized by MB. The in situ formed compounds of TiO2 and CuO/Cu2O were found to absorb visible light, but showed little visible-light-induced photocatalytic activity.