Tailoring visible-light active TiO2/cellulose nanocomposites with controlled crystalline structure for enhanced photocatalytic performance

This work involves a green and simple synthesis of TiO₂ nanoparticles on cellulose under mild conditions without the need for calcination via hydrolysis of titanium oxysulfate (TiOSO₄). The synthesis conditions, such as sulfuric acid concentration (0-10% wt), temperature (70-90 ℃), and time (4-8 h), focused on precisely controlling the structure of TiO₂ to enhance its photocatalytic effectiveness under visible light. At a lower 2.5 wt% sulfuric acid concentration, pure anatase was formed on the cellulose, while an increase in the range of 5.0-7.5 wt% sulfuric acid concentration yielded a rutile phase, resulting in a mixed phase of anatase and rutile on the cellulose. The pure rutile phase was found at a low temperature (70 ℃), while increased temperature led to the formation of the anatase phase. These results confirmed that the formation of crystalline TiO₂ phase on the cellulose depended on sulfuric acid concentration and temperature for hydrolysis. Additionally, the photocatalytic properties of the obtained materials were evaluated by degradationvisible of Rhodamine B (RhB) under UV and visible light. The findings revealed that the mixed phase (anatase/rutile) of TiO₂ on the cellulose demonstrated a superior photocatalytic efficiency (99.2%) compared to pure anatase (85.75%) and rutile (75.08%) when exposed to visible light.