Effective Low-Temperature Oxidative Denitrogenation With Sulfated Titania Supported on Porous Carbon

초록

Carbon-supported sulfated titania (S-TiO2/C) was prepared for the first time by synthesizing the S-TiO2 nanoparticles within the pores of carbon derived from polyaniline. After comprehensive characterization of the catalyst including relevant materials, via X-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), N2 adsorption-desorption, scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM), the material was utilized for the oxidative denitrogenation of model fuel with H2O2 oxidant. A remarkable performance of S-TiO2/C in indole oxidation was confirmed. For example, a low activation energy of 33.6 kJ mol-1 and complete conversion of 1000 ppm of indole within 60 min at 45 degrees C (while 97% conversion was achieved after 60 min at 35 degrees C) were observed. Quinoline might be fully oxidized with the developed catalyst under comparable conditions, with a slight optimization. This performance might be because of the well-dispersed S-TiO2 within the carbon matrix, which facilitates H2O2 activation, after effective adsorption on the catalyst. Radical scavenger and electron spin resonance spectrometry experiments suggested the generation of hydroxyl radicals as reactive oxygen species. Based on the oxidation of methylindole isomers, a mechanism of nucleophilic attack from N of N-containing compounds on hydroxyl radicals could be suggested. The S-TiO2/C catalyst demonstrated excellent reusability, maintaining performance over five cycles, indicating its suitability for oxidative denitrogenation.

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