scholarly journals Molecular Metal Oxide Cluster-Surface Modified Titanium(IV) Dioxide Photocatalysts

2012 ◽  
Vol 65 (6) ◽  
pp. 624 ◽  
Author(s):  
Michael Nolan ◽  
Anna Iwaszuk ◽  
Hiroaki Tada
Keyword(s):  
Surface Modification ◽  
Metal Oxide ◽  
Visible Light ◽  
Uv Light ◽  
Short Review ◽  
Striking Difference ◽  
Oxide Surface ◽  
Metal Oxide Clusters ◽  
Light Activity ◽  
High Level

The surface modification of TiO2 with molecular sized metal oxide clusters has recently been shown to be a promising approach for providing TiO2 with visible-light activity and/or improved UV activity. This short review summarizes the effects of the surface modification of TiO2 with the oxides of iron and tin selected from d- and p-blocks, respectively, on the photocatalytic activity. Fe(acac)3 and [Sn(acac)2]Cl2 chemisorption on the TiO2 surface occurs by ligand-exchange and ion-exchange, respectively. Taking advantage of the strong adsorption, we formed extremely small metal oxide clusters on TiO2 by the chemisorption–calcination cycle (CCC) technique with their loading amount strictly controlled. The iron oxide surface modification of P-25 (anatase/rutile = 4 : 1, w/w, Degussa) gives rise to a high level of visible-light activity and a concomitant increase in the UV-light activity for the degradation of model organic pollutants. On the other hand, only the UV-light activity is increased by the tin oxide surface modification of ST-01 (anatase, Ishihara Sangyo). This striking difference can be rationalized on the basis of the material characterization and DFT calculations, which show that FeOx surface modification of rutile leads to visible-light activity, while SnO2-modified anatase enhances only the UV-light activity. We propose the mechanisms behind the FeOx and SnO2 surface modification, where the surface-to-bulk and bulk-to-surface interfacial electron transfer are taken into account in the former and the latter, respectively.

Photocatalytic properties of Bi/BiOCl heterojunctions synthesized using an in situ reduction method

2014 ◽  
Vol 38 (10) ◽  
pp. 4913-4921 ◽  
Author(s):  
Jiajia Hu ◽  
Guangqing Xu ◽  
Jinwen Wang ◽  
Jun Lv ◽  
Xinyi Zhang ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Reduction Method ◽  
Uv Light ◽  
Photocatalytic Properties ◽  
In Situ Reduction ◽  
Light Activity ◽  
Bi Nanoparticles

Bi nanoparticles on BiOCl nanosheets, synthesized via in situ reduction, enhance the UV light photocatalytic activity and achieve visible light activity.

Study of the Chemical Adsorption Property of Allylsilylazobenzene in the Surface Modification of Nanoporous Alumina Membrane

2013 ◽  
Vol 534 ◽  
pp. 46-52 ◽  
Author(s):  
Kenji Kakiage ◽  
Chie Saito ◽  
Masaki Yamamura ◽  
Toru Kyomen ◽  
Masafumi Unno ◽  
...  
Keyword(s):  
Surface Modification ◽  
Metal Oxide ◽  
Adsorption Property ◽  
Oxide Surface ◽  
Chemical Adsorption ◽  
Reaction Conditions ◽  
Nanoporous Alumina ◽  
Chemical Surface ◽  
Metal Oxide Surface ◽  
Chemical Surface Modification

In order to clarify the chemical adsorption property of allylsilane to metal-oxide surface quantitatively and to obtain the information on the reaction conditions for the efficient surface modification, chemical surface modification of nanoporous alumina membranes (NPAMs) by a typical allylsilyl compound of 4-(allyldimethylsilyl) azobenzene was examined. The chemical surface modification was performed by immersing NPAMs into the solutions of the allylsilylazobenzene. The modification was investigated precisely by estimating the amount of the silylazobenzene adsorbed on the NPAM surface using a visible absorption spectroscopy with changing the temperature, solvent, and the concentration of the solution to reveal the effects of the reaction conditions on the adsorption property of the allylsilane to the metal-oxide surface. The solutions with higher temperatures, non-polar solvents, and higher concentrations were shown to be suitable for the efficient surface modification.

scholarly journals A comparative study of the photocatalytic efficiency of metal oxide/hydroxyapatite nanocomposites in the degradation kinetic of ciprofloxacin in water

2020 ◽  
Vol 150 ◽  
pp. 02006
Author(s):  
Jihane Labrag ◽  
Chaimaa El Bekkali ◽  
Ikrame Es-Saidi ◽  
Habiba Bouyarmane ◽  
Abdelaziz Laghzizil ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Surface Area ◽  
Uv Light ◽  
Oxide Surface ◽  
Sorption Behavior ◽  
Photocatalytic Efficiency ◽  
Operational Parameters ◽  
Degradation Kinetic ◽  
Photodegradation Efficiency ◽  
Pore Size Distributions

The photocatalytic efficiency of the metal oxide-hydroxyapatite photocatalysts prepared by soft chemistry using phosphate rock as calcium and phosphorus precursors has been investigated on the degradation kinetic of ciprofloxacin residues in water under UV-light (HPK125 W Lamp). The nature of metal oxide (TiO2, ZnO, Fe2O3), structure, surface area and pore-size distributions of the catalysts were analyzed by various techniques analyses. Association of nanoscale metal oxide with hydroxyapatite could enhance the sorption properties of the materials and confers them interesting photodegradation properties. The results of the kinetic study revealed that the activities of these photocatalysts were dependent on the oxide surface and the best activity was obtained with TiO2/hydroxyapatite catalyst, which had the largest surface area. The effects of various operational parameters were thoroughly considered in order to achieve highest photodegradation efficiency. A correlation between the nature of associated metal oxide, surface properties, the sorption behavior and the photodegradation capacity of these composites could be establishedd.

scholarly journals Visible light photocatalytic activity of TiO2 deposited on activated carbon

2013 ◽  
Vol 11 (3) ◽  
pp. 464-470 ◽  
Author(s):  
Alexander Eliyas ◽  
Ljutzkan Ljutzkanov ◽  
Irina Stambolova ◽  
Vladimir Blaskov ◽  
Sasho Vassilev ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Activated Carbon ◽  
Visible Light ◽  
Uv Light ◽  
Original Method ◽  
Light Illumination ◽  
Porous Texture ◽  
Visible Light Photocatalytic Activity ◽  
Light Activity ◽  
Visible Light Photocatalytic

AbstractAbstract Four photocatalyst samples, prepared from beech sawdust, were synthesized by an original method, combining pyrolysis and impregnation — two of them: TiO2 + activated carbon and other two — only activated carbon. The pyrolysis process has been carried out at two different temperatures — 680°C and 830°C. The prepared samples were characterized by a series of methods — XRD, BET, SEM and DTA/TG. The most important result was achieving visible light photocatalytic activity with an azo dye pollutant for both materials. The TiO2/AC-680°C sample demonstrated higher activity under visible light illumination than the TiO2/AC-830°C sample. The visible light activity was attributed to the active carbon component in the composite materials, which was evidenced by the photocatalytic tests with bare carbon (without any TiO2) manifesting visible light activity. The AC-680°C carbon was superior to the AC-830°C under visible illumination probably due to its higher specific surface area and porous texture. UV-light testing of the photocatalytic activity revealed that the TiO2/AC-680°C sample was higher than that of the TiO2/AC-830°C under polychromatic UV-A illumination (320–400 nm with a maximum at l = 365 nm). The TiO2/AC-680°C sample was also more efficient with the monochromatic UV-C illumination (l = 254 nm). Graphical abstract

A bi-overlayer type plasmonic photocatalyst consisting of mesoporous Au/TiO2 and CuO/SnO2 films separately coated on FTO

2015 ◽  
Vol 17 (27) ◽  
pp. 18004-18010 ◽  
Author(s):  
Shin-ichi Naya ◽  
Takahiro Kume ◽  
Nozomi Okumura ◽  
Hiroaki Tada
Keyword(s):  
Liquid Phase ◽  
Visible Light ◽  
Gas Phase ◽  
Plasmonic Photocatalyst ◽  
Light Activity ◽  
High Level

A bi-overlayer type “plasmonic photocatalyst” consisting of Au/mp-TiO2 and CuO/mp-SnO2 separately formed on the FTO substrate exhibits a high level of visible-light activity for the gas-phase and liquid-phase reactions.

scholarly journals UV Blocking Glass: Low Cost Filters for Visible Light Photocatalytic Assessment

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Charles W. Dunnill
Keyword(s):  
Visible Light ◽  
Light Transmission ◽  
Uv Light ◽  
Low Cost ◽  
False Negative ◽  
Double Layers ◽  
Uv Blocking ◽  
Negative Results ◽  
Light Activity ◽  
Visible Light Photocatalytic

A number of commercially available art protection products have been compared and assessed for their suitability as UV blocking filters in the application of “visible light” photocatalytic research. Many groups claiming visible light photocatalytic success employ filters to block out stray UV radiation in order to justify that their photocatalysts are indeed visible light photocatalysts and not UV light photocatalysts. These filters come in varying degrees of ability and price and many authors fail to correctly characterise their filters in individual papers. The use of effective filters to prevent both false positive and false negative results is important to maintain scientific rigor and create accurate understanding of the subject. The optimum UV filter would have the highest UV blocking properties (<390 nm) and simultaneously the highest visible light transmission (390–750 nm). Single and double layers of each of the glass products were assessed as well as laminate products. The conclusions show an inexpensive and highly effective setup for the conduction of visible light photochemistry that should be incorporated as a standard part in any researcher’s work where the claim of visible light activity is made.

Preparation and Properties of Titanium Oxide Photocatalyst with Visible Light Activity

2007 ◽  
Vol 280-283 ◽  
pp. 377-380 ◽  
Author(s):  
Lei E ◽  
Ming Xia Xu ◽  
Lei Ge ◽  
Yu Ming Tian ◽  
Yan Li ◽  
...  
Keyword(s):  
Visible Light ◽  
Ph Value ◽  
Uv Light ◽  
Hydrolysis Product ◽  
Treatment Temperature ◽  
Absorption Feature ◽  
Visible Light Region ◽  
Light Region ◽  
Light Activity ◽  
Different Temperatures

TiO2 photocatalyst were obtained from the hydrolysis product of TiOSO4 with ammonia and the photocatalytic activities were investigated by the photocatalytic degradation of methyl orange aqueous solution under UV-light and visible-light. The results showed that the absorption intensity in visible-light was dependent on the concentration of the materials, pH value and heat-treatment temperature. The color of the TiO2 varied from yellowish to vivid yellow when the TiO2 was calcined at different temperatures from 300°C to 500°C for 1h. The photocatalytic activity of TiO2 under visible light was determined by the photo-absorption feature in visible light region, which was related to the heattreatment temperature. The TiO2 calcined at 400°C shows stronger photo-absorption in visible light region and exhibits higher visible-light activity than the TiO2 calcined at other temperature.

Sign in / Sign up

Export Citation Format

Share Document