Degradation of Rhodamine B dye using the mesoporous material KIT-6/TiO₂ photocatalyst obtained by in situ anchoring...

In this study, a novel synthesis approach was employed to create the KIT-6/TiO₂ photocatalyst with different ratios of Si/Ti. The results of the X-ray diffraction revealed that incorporating TiO₂ with the anatase phase maintained the mesoporous structure of KIT-6 (Korean Institute of Technology 6). The scanning electron microscope and transmission electron microscope images exhibited unobstructed mesopores, validating their anchoring within the internal structure of the support. Furthermore, nitrogen adsorption-desorption studies confirmed the presence of TiO₂ within the pores. X-ray photoelectron spectroscopy (XPS) analysis corroborated the successful incorporation of TiO₂, showing the presence of Ti⁴⁺ and Ti³⁺ species, with Ti³⁺ indicating the presence of oxygen vacancies that enhance photocatalytic performance. Photodegradation efficiency was assessed for Rhodamine B, achieving 95% and 86.5% for KIT-6/TiO₂ (Si/Ti = 25) and KIT-6/TiO₂ (Si/Ti = 75), respectively. The molar ratio Si/Ti = 25 exhibited higher activity, which can be attributed to a better distribution of active sites, as confirmed by the measurement of turnover frequency (TOF = 2.0 × 10^-2 min^-1). The stability of the KIT-6/TiO₂ (Si/Ti = 25) has also been investigated, and stable performance in recycling photocatalytic reactions was obtained after four cycles of use. The scavengers used indicated that the superoxide anion radical (•O₂^-) and electron (e^-) were the major active species. This study successfully demonstrated the incorporation of TiO₂ into the walls of mesoporous materials using the ISA method, achieving high photocatalytic efficiency. Moreover, this method enabled superior performance with a reduced amount of photocatalyst compared to a pure TiO₂ sample.