Electronic Resource
Sol-gel pure and mixed-phase titanium dioxide for photocatalytic purposes: Relations between phase composition, catalytic activity, and charge-trapped sites
| العنوان: | Sol-gel pure and mixed-phase titanium dioxide for photocatalytic purposes: Relations between phase composition, catalytic activity, and charge-trapped sites |
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| المؤلفون: | Scotti, R, Bellobono, I, Canevali, C, Cannas, C, Catti, M, D'Arienzo, M, Musinu, A, Polizzi, S, Sommariva, M, Testino, A, Morazzoni, F, SCOTTI, ROBERTO, CANEVALI, CARMEN, CATTI, MICHELE, MORAZZONI, FRANCA, Bellobono, IR, D'ARIENZO, MASSIMILIANO |
| بيانات النشر: | American Chemical Society 2008 |
| نوع الوثيقة: | Electronic Resource |
| مستخلص: | The sol-gel synthesis of TiO2 from TiCl4 assisted by the triblock copolymer EO20-PO70 -EO20 (EO = -CH2CH2O-, PO = -CH2 (CH3)CHO-) as templating agent was carried out by systematically changing H2O:Ti (rw) and HCl:Ti (ra) molar ratios. Mesoporous and nanocrystalline TiO2 samples with well-defined and controlled phase composition (anatase, rutile, and mixed phase) were obtained after calcination at 400 °C and characterized for the morphology, particle size, and shape using TEM, HRTEM, XRD, and surface area measurements. The role of rw and ra and influence of the copolymer in determining the phase composition was demonstrated. Rutile becomes the main phase by increasing rw. In fact, the decrease of Ti concentration slows down the condensation rate, favoring formation of rutile seeds in the gel. The photocatalytic activity of TiO2 in the UV photomineralization of phenol depends on the phase composition and oxidizing agent, H2O2 or O2. When the oxidation is performed by H2O2, rutile, formed by large crystalline rods with high aspect ratios (size 15-20 × 100-120 nm), shows higher catalytic activity with respect to the small, almost cubic, anatase particles (5-15 nm). If O2 is used, the catalytic activity generally decreases and the behavior of polymorphous species is reverse. EPR investigation of the paramagnetic charge carriers, formed under UV irradiation at 10 K, showed the resonance lines of holes trapped at O- lattice sites and electrons trapped at Ti3+ and O2- sites. The rutile crystalline rods present the largest quantity of O- and Ti3+ centers. The overall results suggest correlation between TiO2 particle size and shape and the photocatalytic activity |
| مصطلحات الفهرس: | Sol-gel, Titanium dioxide, Photocatalysis, info:eu-repo/semantics/article |
| URL: | info:eu-repo/semantics/altIdentifier/wos/WOS:000256854800039 volume:20 issue:12 firstpage:4051 lastpage:4061 journal:CHEMISTRY OF MATERIALS |
| الاتاحة: | Open access content. Open access content |
| ملاحظة: | English |
| Other Numbers: | ITBAO oai:boa.unimib.it:10281/6337 10.1021/cm800465n info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-47649093945 1308893206 |
| المصدر المساهم: | BICOCCA OPEN ARCH From OAIster®, provided by the OCLC Cooperative. |
| رقم الانضمام: | edsoai.on1308893206 |
| قاعدة البيانات: | OAIster |
| الوصف غير متاح. |