Charge separation at the rutile/anatase interface: a dominant factor of photocatalytic activity

Miyagi, Takahira; Kamei, Motohiro; Mitsuhashi, T.; Ishigaki, Takamasa; Yamazaki, Atsushi

doi:10.1016/j.cplett.2004.04.042

Cited by 139 publications

(115 citation statements)

References 9 publications

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“…This allotropic form of titanium dioxide has an unusual microstructure, within which anatase and rutile particles can interact with a synergetic effect [45]. The increase in charge-separation efficiency, resulting from interfacial electron-transfer at the interface between anatase and rutile, increases its photocatalytic activity [46] [47].…”

Section: Effect Of Catalyst Typementioning

confidence: 99%

A Study on the Degradation of Carbamazepine and Ibuprofen by TiO<sub>2</sub> & ZnO Photocatalysis upon UV/Visible-Light Irradiation

Georgaki¹,

Vasilaki²,

Katsarakis³

2014

AJAC

100

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The degradation of carbamazepine (CBZ) and ibuprofen (IBP) in aqueous matrices was investigated by TiO2 and ZnO photocatalysis initiated by UV-A and visible-light irradiation. Emphasis was given on the effect of operating parameters on the degradation effectiveness, such as catalyst type and loading (50 -500 mg/L), initial drug concentration (10, 40, 80 mg/L) and wavelength of irradiation (200 -600 nm). In an effort to understand the photocatalytic pathway for CBZ and IBP removal in terms of primary oxidants, the contribution of HO• was evaluated. With this scope, the radical-mediated process was suppressed by addition of an alcohol scavenger, isopropanol, (i-PrOH), described as the best free hydroxyl radical quencher. The photodegradation rate of the pharmaceuticals was monitored by high performance liquid chromatography (HPLC). According to the results, visible-light exposure, at λexc > 390 nm, takes place as a pure photocatalytic degradation reaction for both compounds. IBP was found to have overall high conversion rates, compared to CBZ. IBP oxidized fast under photocatalytic conditions, regardless the adverse effect of the increase of initial drug concentration, or low catalyst load, irradiation upon visible-light, by either titania or zinc oxide. Finally, addition of isopropanol showed a significant inhibition effect on the CBZ degradation, taken as an evidence of a solution-phase mechanism. In the case though of IBP degradation, the hole mechanism may be prevailing, suggested by the negligible effect upon addition of isopropanol indicating a direct electron transfer between holes (h + ) and surface-bound IBP molecules. A plausible mechanism of IBP and CBZ photocatalysis was proposed

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Section: Effect Of Catalyst Typementioning

confidence: 99%

A Study on the Degradation of Carbamazepine and Ibuprofen by TiO<sub>2</sub> & ZnO Photocatalysis upon UV/Visible-Light Irradiation

Georgaki¹,

Vasilaki²,

Katsarakis³

2014

AJAC

100

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“…The reason for this higher activity should be attributed to the combined effect of the higher surface adsorptive capacity of anatase and its higher rate of hole trapping. Recently, studies have shown that mixtures of anataserutile or brookite-anatase were more active than anatase alone (33,34).…”

Section: Visai Et Almentioning

confidence: 99%

Titanium Oxide Antibacterial Surfaces in Biomedical Devices

et al. 2011

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Int J Artif Organs ( 2011; : 9) 929-946 34 TITANIUM OXIDE AND ANTIBACTERIAL SURFACES IN BIOMEDICAL DEVICES Device-related infections: a clinical demand driving material science researchAn increasing number of clinical procedures requires the use of biomedical devices, whose widespread presence in modern therapeutic treatments is driving the demand for better performances and longer reliability. One of the major issues of both short-term devices and implantable prostheses is represented by device-related infections (DRIs) Accepted: August 31, 2011 rEViEW due to bacterial colonization and proliferation (1). About half of the 2 million cases of nosocomial infections that occur each year in the United States are associated with indwelling devices (2): these infections generally require a longer period of antibiotic therapy and repeated surgical procedures, resulting in potential risks for the patient and increased costs for the healthcare system. The planktonic bacteria that colonize a device surface tend to form a biofilm and the sessile bacterial cells, enclosed in a self-produced polymeric matrix of this kind, can withstand host immune responses and generally show extraordinary antibiotic resistance (3). Eventually, bacteria rapid multiply and disperse in planktonic form, giving rise

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“…Research has indicated that the conduction band of anatase is shifted negatively by 0.2 V with regard to that of rutile. [47][48][49][50] This implies that the photogenerated potential of anatase can also be more negative than that of rutile. This matches with our results.…”

Section: Resultsmentioning

confidence: 99%

Long-Term Photoelectrochemical Cathodic Protection by Co(OH)₂-Modified TiO₂on 304 Stainless Steel in Marine Environment

Xie

Liu

Chen

et al. 2018

J. Electrochem. Soc.

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The long-term photoelectrochemical cathodic protection by Co(OH) 2 -surface modified TiO 2 of anatase nanotubes and rutile type, prepared by anodic oxidation has been studied in aqueous 3.5 wt% NaCl solution. Electrochemical measurements have been used to evaluate the photoelectrochemical protective properties of both Co(OH) 2 -modified TiO 2 coupled with 304 stainless steel in 3.5 wt% NaCl solution under illumination and in the dark. Morphologies, crystal structures, surface compositions, and light response range of both Co(OH) 2 -surface modified TiO 2 films before and after immersion were characterized, respectively, by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-Vis spectrophotometry. The results show that the photogenerated electrode potential of both types of TiO 2 films modified with Co(OH) 2 is more negative affording protection of 304 stainless steel than that of the non-modified TiO 2 under illumination. These TiO 2 films provide a long period (12 h) of protection. The anatase-TiO 2 nanotube film always shows a better protection performance than rutile-TiO 2 film. In recent years, photocatalysis has been broadly used in solar cells, for degradation of pollutants, splitting of water, air purification, and corrosion protection of metals.1-3 The latter application has attracted our attention because of its environmental advantages.In 1990s, Tsujikawa and Yuan 4 first proposed the method of photoelectrochemical cathodic protection of metals by photocatalytic materials. They reported the more negative corrosion potential of TiO 2 -coated 304 stainless steel or carbon steel under UV irradiation than that of bare steel. The TiO 2 coating plays the role of providing electrons like a sacrificial anode in cathodic protection. Subsequently, Fujishima et al.5 studied the mechanism of the photoelectrochemical cathodic protection of TiO 2 -WO 3 in 3 wt% NaCl solution with pH = 5. So far, TiO 2 -protection of metals using sunlight has been a focus of great attention as a possible means for converting solar energy to electrical energy by generating the required negative electrode potential. Photoelectrochemical cathodic protection has become an active research field of metal corrosion protection. It has attracted numerous studies and yielded new technologies. [6][7][8][9][10][11][12][13] Many metal oxides and sulfides, such as TiO 2 , 4,9 ZnO, 14 SnO 2 15 and CdS, 16 have been investigated as common photocatalyst materials. TiO 2 is most widely used in current applications because of its high catalytic activity, good resistance to photocorrosion, chemical stability, cheapness, and non-toxicity. 4,[17][18][19] Of the three crystal modifications of TiO 2 , the wide bandgap forms anatase (3.2 eV) and rutile (3.0 eV) are mainly employed in photocatalytic reactions. 20,21 However, photocatalytic materials still have problems in the marine environment. Corrosion is a gradual and long-term destruction of materials. Therefore...

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Charge separation at the rutile/anatase interface: a dominant factor of photocatalytic activity

Cited by 139 publications

References 9 publications

A Study on the Degradation of Carbamazepine and Ibuprofen by TiO<sub>2</sub> & ZnO Photocatalysis upon UV/Visible-Light Irradiation

A Study on the Degradation of Carbamazepine and Ibuprofen by TiO<sub>2</sub> & ZnO Photocatalysis upon UV/Visible-Light Irradiation

Titanium Oxide Antibacterial Surfaces in Biomedical Devices

Long-Term Photoelectrochemical Cathodic Protection by Co(OH)₂-Modified TiO₂on 304 Stainless Steel in Marine Environment

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Charge separation at the rutile/anatase interface: a dominant factor of photocatalytic activity

Cited by 139 publications

References 9 publications

A Study on the Degradation of Carbamazepine and Ibuprofen by TiO&lt;sub&gt;2&lt;/sub&gt; &amp; ZnO Photocatalysis upon UV/Visible-Light Irradiation

A Study on the Degradation of Carbamazepine and Ibuprofen by TiO&lt;sub&gt;2&lt;/sub&gt; &amp; ZnO Photocatalysis upon UV/Visible-Light Irradiation

Titanium Oxide Antibacterial Surfaces in Biomedical Devices

Long-Term Photoelectrochemical Cathodic Protection by Co(OH)2-Modified TiO2on 304 Stainless Steel in Marine Environment

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A Study on the Degradation of Carbamazepine and Ibuprofen by TiO<sub>2</sub> & ZnO Photocatalysis upon UV/Visible-Light Irradiation

A Study on the Degradation of Carbamazepine and Ibuprofen by TiO<sub>2</sub> & ZnO Photocatalysis upon UV/Visible-Light Irradiation

Long-Term Photoelectrochemical Cathodic Protection by Co(OH)₂-Modified TiO₂on 304 Stainless Steel in Marine Environment