Modulation of physical and photocatalytic properties of (Cr, N) codoped TiO₂ nanorods using soft solution processing

Facile polymerized complex reactions together with a hydrothermal reaction were implemented to make single crystalline TiO₂ nanorods for the first time. Chromium (Cr) and nitrogen (N₂) co-doping was performed to tailor the physical properties. Transmission electron microscopy and x-ray diffraction study illustrated that highly reactive facets of (101), (111), and (001) dominated rutile TiO₂ nanorods. A growth model, based on formation of complex species, was proposed to elucidate effectiveness of the soft solution processing in making TiO₂ nanorods. X-ray photoelectron spectroscopy analysis and consideration of fundamentals of charge neutrality showed N₂ doping could inhibit formation of Cr⁶⁺ and oxygen vacancies (V_O²⁺). An investigation of the photocatalytic properties exhibited high efficiency of photodegradation of methylene blue in 15 min under pH = 10, using a nanocomposite of (7% Cr, 0.0021% N) codoped and 3% Cr doped TiO₂ nanorods.