Enhanced photocatalytic activity of cobalt-doped titanate nanotube heterostructures decorated with Cu2O-CuO nanoparticles for organic pollutant degradation under UV and visible irradiation

Abstract

In this work, Co-doped titanate nanotubes decorated with Cu2O/CuO nanoparticle heterostructures (TNTs-Co-Cu) were successfully synthesized by hydrothermal method followed by an impregnation method. The photocatalysts were characterized by TEM, XRD, Raman spectroscopy, XPS, N2 adsorption/desorption, DRS, and Photoluminescence. The results confirm the success of the TNTs-Co-Cu heterojunctions synthesis and the excellent absorption exhibited in the visible light region. Furthermore, the photocatalytic activity of the TNTs-Co-Cu materials was higher than that of pure titanate nanotubes (TNTs) and doped with cobalt (TNTs-Co) for Methyl Blue (MB) photodegradation under UV and visible light irradiation. The improved photocatalytic activity may can explained due to the increased the lifetime of photogenerated electron/hole pairs. The photocatalytic mechanism study suggested that the photogenerated electrons in conduction band (CB) of the Cu2O flow through the CuO CB to CB of TNTs-Co, whereas the photogenerated holes migrate in the opposite direction. These transfers result in the production of O2– and OH radicals to promote the photooxidation reaction of MB. This study provides the understanding on the heterojunction mechanism of the MB photodegradation by TNTs-Co-Cu under UV irradiation and shows their high photocatalytic activity after 5 cycles, which make the TNTs-Co-Cu a promising photocatalyst for the multifunctional heterogeneous photocatalysis applications.