Systematic variation of preparation time, temperature, and pressure in hydrothermal synthesis of macro-/mesoporous TiO2 for photocatalytic air treatment
| Autor: | Alireza Haghighat Mamaghani, Chang-Seo Lee, Fariborz Haghighat |
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| Rok vydání: | 2019 |
| Předmět: |
Terephthalic acid
Chemistry Scanning electron microscope General Chemical Engineering General Physics and Astronomy 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Crystallinity chemistry.chemical_compound Chemical engineering Air treatment Photocatalysis Hydrothermal synthesis Fourier transform infrared spectroscopy 0210 nano-technology Mesoporous material |
| Zdroj: | Journal of Photochemistry and Photobiology A: Chemistry. 378:156-170 |
| ISSN: | 1010-6030 |
| DOI: | 10.1016/j.jphotochem.2019.04.022 |
| Popis: | A series of porous TiO2 photocatalysts are prepared, by systematically varying the preparation conditions (time, temperature, or pressure (i.e. filling ratio)), characterized, and evaluated in photocatalytic oxidation of toluene and methyl ethyl ketone (MEK) to explore preparation-property-performance relationships. A detailed characterization has been conducted via X-ray diffraction (XRD), N2 adsorption-desorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), and UV–vis spectroscopy. Furthermore, hydroxyl radical ( OH) generation on the surface of TiO2 is measured by a photoluminescence (PL) method using terephthalic acid (TA) as probe molecule. All the hydrothermally-prepared samples possessed good crystallinity (79.5–89 %), large surface area (134.9–237.2 m2/g), small crystal size (5.9–10 nm), and mesoporous structure. SEM images revealed presence of macropores and marcochannels, and N2 adsorption-desorption and TEM analyses indicated a significant amount of mesopores. PL and XRD results demonstrated a good proportionality between surface area normalized OH generation and crystallinity. The complex interplay among various properties (especially crystallinity and surface area) led to appearance of activity optimums. Photocatalyst prepared at 12 h, 200 °C, and 80% filling ratio exhibited the best toluene and MEK removal efficiencies, which surpass those of P25 by factors of 2.08 and 1.85 times, respectively. The superior photocatalytic activity of developed TiO2 catalysts might be attributed to high surface area and existence of meso-/macropores that provide a large number of active sites, and facilitate light penetration and pollutants diffusion. The presented property-activity relationships can be utilized as potential design criteria for the development of new TiO2 photocatalysts for air purification. |
| Databáze: | OpenAIRE |
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