Preparation of extremely smooth and boron-fluorine co-doped TiO2 nanotube arrays with enhanced photoelectrochemical and photocatalytic performance

Abstract Highly ordered TiO 2 nanotube arrays (BF-TNTs) are prepared by anodization method in the unique NH 4 BF 4 based electrolyte. The results show that the tube walls of the BF-TNTs, by first using NH 4 BF 4 based electrolyte, are much smoother than that of TiO 2 nanotube arrays (F-TNTs) fabricated with a conventional fluoride containing electrolyte. In the NH 4 BF 4 electrolyte, boron and fluorine elements are simultaneously doped into the obtained BF-TNTs during the anodization process. The BF-TNTs exhibit better photoelectrochemical (PEC) properties and photocatalytic (PC) performance than those of F-TNTs.