Nitrogen assisted one-step hydrothermal synthesis of commercial TiO2 for methylene blue degradation under visible light irradiation

Strategies to make more efficient use of sunlight have been developed. Different synthesis parameters have been studied for the production of multiphase photocatalysts. In this work, for the first time, the performance of a one-step nitrogen-assisted hydrothermal synthesis of TiO2 using TiO2–P25 as a Ti precursor was investigated for the degradation of methylene blue under visible light irradiation. Urea and ethylenediamine (EDA) were evaluated as nitrogen sources. The produced photocatalysts had a rod-like nanostructure with the formation of mesopores. The resulting phase was a heterojunction of anatase, TiO2(B), and rutile, which enhanced charge separation. The presence of nitrogen during the hydrothermal reaction altered the morphology of TiO2, impacting the crystallite size. The U photocatalyst (urea source) achieved the best result for visible light with prior adsorption, degrading around 11 % of methylene blue in 5 h. This shows that it is possible to obtain a photocatalyst with superior performance to TiO2–P25 under both ultraviolet and visible light. This study presents an efficient strategy for improving the optical response of TiO2 by using nitrogen during a hydrothermal reaction, which has potential for industrial applications.