Fabrication of CdS/H-TiO2 Nanotube Arrays and Their Application for the Degradation of Methyl Orange in Aqueous Solutions

The fabrication and characterization of heterogeneous structures based on CdS and self-doped TiO2 nanotube arrays (H-TNTs) are reported for the first time. CdS was conformally deposited onto TiO2 nanotube arrays (TNTs) using a simple method of electrochemical atomic layer deposition. The as-prepared samples were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV-Vis diffusion reflection spectroscopy (UV-Vis DRS), and photoluminescence spectroscopy (PL) techniques. Compared with pure TNTs, CdS/H-TNTs exhibit enhanced photoelectrochemical properties and photocatalytic activity under visible light. Self-doping introduces oxygen vacancies and Ti3+ species, and the electrochemical deposition technique promotes the deposition of CdS onto TiO2 nanotube walls, forming a heterojunction compact structure and resulting in decrease in photocatalytic activity under visible light