Preparation of Ti³⁺/N-co-doped TiO₂ by one-step hydrothermal synthesis method with high photocatalytic degradation performance under visible light

Ti³⁺/N-co-doped TiO₂ was successfully synthesized in situ by one-step hydrothermal method using tetrabutyl titanate (TBOT) as the titanium source and hydrazine hydrate as the reducing agent and nitrogen source. Afterward, the microstructure and physicochemical properties of the catalysts were characterized by transmission electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, UV–vis diffuse reflectance spectroscopy, and photoluminescence spectroscopy. Results indicated that nitrogen was effectively doped into the lattice of TiO₂ and Ti³⁺ was stably presented in the prepared TiO₂, which reduced the band-gap TiO₂ (2.96–2.75 eV) and enhanced photo-induced charge separation efficiency under visible light. In addition, the photocatalytic activity was evaluated by degradation of rhodamine B under xenon lamp with 420 nm filter. With the amount of hydrazine hydrate increased, the photocatalytic degradation performance of the sample increased first and then decreased. When the volume ratio of hydrazine hydrate to TBOT was 1:5, the sample showed the best photocatalytic performance.