Ultra-deep Photocatalytic Oxidative Desulfurization of Model Fuel Using Ti-UiO-66(Zr) Metal–Organic Framework.

Titanium modified UiO-66(Zr)-type metal–organic framework (MOF) nanophotocatalysts have been prepared via a modified one-step solvothermal methodology and evaluated in photocatalytic oxidative desulfurization. Extensive characterization by X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), ultraviolet–visible diffuse reflectance spectroscopy (UV–vis DRS), photoluminescence spectroscopy (PL), nitrogen adsorption–desorption, and thermogravimetric analysis (TGA), have revealed the role of Ti loading, on Ti speciation and the structure of the synthesized materials. The performance of nanophotocatalysts have been evaluated for photocatalytic oxidative desulfurization (PODS). PODS reaction parameters, including temperature, photocatalyst dosage, oxidant to sulfur ratio, and solvent to fuel ratio, were optimized, with dibenzothiophene (DBT) conversion reaching 100% under optimal conditions (T = 50 °C, photocatalyst dosage = 2 g/L, oxidant to sulfur molar ratio (O/S = 8), and solvent/fuel = 1). Recyclability studies performed for the optimal catalyst showed good stability over six recycles, with total conversion dropping by only 18%. Kinetic studies showed that DBT PODS follows pseudo-first-order kinetics, with an activation energy value of 55.1 kJ mol−1. [ABSTRACT FROM AUTHOR]