New insights regarding the calcination as a critical parameter in the synthesis of sol–gel made titania powders

Mogyorósi, Károly; Karácsonyi, É.; Cegléd, Zs.; Dombi, András; Danciu, Virginia; Baia, Lucian; Pap, Zsolt

doi:10.1007/s10971-012-2897-1

Cited by 6 publications

(3 citation statements)

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“…4) revealed an interesting order of the holes throughout the plates. The observed high level order of the "crystallographic" holes clearly suggested that their formation mechanism is not related to the calcination specific phenomena at all, such as water/other organics loss (if that was the case, then volcano-like craters should have been observed as already shown in our recent papers, both at nano/ macro scale 31,34 ).…”

Section: Structural Features Of the Obtained Micro-materialssupporting

confidence: 61%

“Crystallographic” holes: new insights for a beneficial structural feature for photocatalytic applications

et al. 2015

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One of the most fundamental aspects of the heterogeneous catalysis field is the manipulation of the catalysts' activity. In photocatalysis this is carried out by maximizing the right crystal plane of a semiconductor oxide. Until now, most of the papers have achieved this by a combination of different oxides, with noble metals and sometimes with carbon nanomaterials. In this work MWCNTs (multiwalled carbon nanotubes) were applied as "crystallization promoters" in a very simple, safe, one-step hydrothermal method. By this method TiO 2 nano/micro crystals with exposed {001} facets were obtained in the first step. The next episode in the crystal manipulation "saga" was the modification of the (001) crystallographic plane's structure by creating ordered/own faceted "crystallographic holes". These elements are capable of further enhancing the obtained activity of titania microcrystals to a higher extent, as shown by the UV driven photocatalytic phenol degradation experiments. The appearance of the holes was "provoked" by simple calcination and their presence and influence were demonstrated by XPS and HRTEM.

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Section: Structural Features Of the Obtained Micro-materialssupporting

confidence: 61%

“Crystallographic” holes: new insights for a beneficial structural feature for photocatalytic applications

et al. 2015

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“…In the Ti 2p XPS spectrum only Ti 4+ was detected, while the O 1s spectrum revealed the usual components: oxide oxygen from TiO 2 (530.3 eV), surface OH group oxygen (532 eV), and oxygen from H 2 O (532.8 eV). As the Rutile-RHSE-900 was made by the rapid heat treatment method, 27,28,34 we expected the appearance of new spectral features. Indeed, in the Ti 2p XPS spectrum a small amount of Ti 3+ was observed (13 at%: peaks at 457.3 eV and 461.9 eV), along with Ti 4+ (87 at%: peaks at 459.1 eV and 464.8 eV).…”

Section: Discussionmentioning

confidence: 99%

Visible light driven photocatalytic elimination of organic- and microbial pollution by rutile-phase titanium dioxides: new insights on the dynamic relationship between morpho-structural parameters and photocatalytic performance

et al. 2015

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The characteristic properties and the resulted photocatalytic efficiencies of rutile-phase titanium dioxides were investigated in the present study. A series of rutile with different primary particle sizes (5.2-290 nm) were produced by a sol-gel method followed by calcination and were characterized by XRD, DRS, TEM, XPS, EPR, IR and N 2 adsorption. Their photocatalytic efficiencies were determined in the decomposition of phenol, and in the inactivation of E. coli bacteria under visible light irradiation. The results were compared with the photocatalytic performance of commercial Aldrich rutile and Aeroxide P25 powders. Of the noncommercial products, the TiO 2 with the smallest particle size displayed the highest efficiency, while the surface-normalized photocatalytic performance was significantly higher for the larger rutile particles. This can be explained by the red shift of light absorption at higher calcination temperatures. Although Aldrich rutile and the corresponding laboratory-made photocatalyst exhibited similar structural features (e.g. particle size, specific surface area, morphology and light absorption), the latter proved to be less efficient despite its Ti 3+ content (while Aldrich rutile contains only Ti 4+ ). The main reason for the much higher photocatalytic performance was the presence of Ti-O-O-entities on the surface of Aldrich rutile. On the basis of these results, in the case of rutile-phase titanium dioxide, the presence of Ti-O-O-entities was more beneficial, than the presence of Ti 3+ and low-binding-energy oxygen (which indicates defects) in relation with the photocatalytic performance under visible light irradiation.

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“…Mivel a Rutil-RHSE-900 titán-dioxidot a korábban ismertetett RHSE módszerrel [200,234,235] O1s spektrumban, a szokásos oxigénformák mellett "alacsony kötési energiájú" oxigén is megjelenik (528.8 eV; 12 atom%). Kutatócsoportunk korábbi eredményei alapján [200,234], ez az oxigén-jel hibahelyeket, illetve Ti 3+ atomokhoz kapcsolódó oxigén atomokat jelöl.…”

Section: Röntgen Fotoelektron Spektroszkópiával Végzett Mérések Eredmunclassified

Környezeti szennyezők ártalmatlanítása UV- és látható fényre aktív titán-dioxid alapú fotokatalizátorokkal

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New insights regarding the calcination as a critical parameter in the synthesis of sol–gel made titania powders

Cited by 6 publications

References 10 publications

“Crystallographic” holes: new insights for a beneficial structural feature for photocatalytic applications

“Crystallographic” holes: new insights for a beneficial structural feature for photocatalytic applications

Visible light driven photocatalytic elimination of organic- and microbial pollution by rutile-phase titanium dioxides: new insights on the dynamic relationship between morpho-structural parameters and photocatalytic performance

Környezeti szennyezők ártalmatlanítása UV- és látható fényre aktív titán-dioxid alapú fotokatalizátorokkal

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