A novel approach for enhanced visible light activity in doped nanosize titanium dioxide through the excitons trapping

Journal Article · Wed Feb 15 04:00:00 EST 2012 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2011.11.052· OSTI ID:21612904

Jaimy, Kanakkanmavudi B; Baiju, K V; Ghosh, Swapankumar ^[1]; Warrier, K G.K., ^[1]

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1. National Institute for Interdisciplinary Science and Technology, CSIR, Trivandrum 695019 (India)

Titanium dioxide doped with iron oxide (0-10 mol%) has been synthesized by an aqueous sol-gel method. The extent of phase transformation is higher in presence of up to 1 mol% of Fe{sup 3+} ions in doped titania. A further increase in Fe{sup 3+} content was found to decrease the phase transformation. A composition which contains {approx}90% rutile and the remaining anatase phase shows the highest photocatalytic activity. Even though surface area values are dramatically decreased by the modification of TiO{sub 2} by Fe{sup 3+} doping, crystallinity plays a major role in photocatalytic activity enhancement. UV-vis reflectance spectra indicate a red-shift in band gap energy and thus an enhanced photoactivity in visible light, suitable for application in photodegradation of toxic industrial effluents as well as other organic contaminants, is achieved. Low concentrations of Fe{sup 3+} ions act as excitons trapping centers, while higher concentrations act as recombination centers. The synergy between the rutile-anatase ratios and optimum amount of Fe{sup 3+} ions improve the interfacial charge transfer and trapping which enhanced the photochemical degradation of MB dye. The Fe{sup 3+} doped TiO{sub 2} composition has the highest photoactivity, having an apparent rate constant of 11.1 Multiplication-Sign 10{sup -3} min{sup -1}, which is much higher than that of commercial P25 Degussa titania (6.03 Multiplication-Sign 10{sup -3} min{sup -1}). - Graphical abstract: Model explaining the transfer and trapping of e{sup -}/h{sup +} pairs in mixed phase titania by Fe{sup 3+} ions suggests the reason for the increased lifetime of e{sup -}/h{sup +} pairs and enhanced photocatalytic activity. Highlights: Black-Right-Pointing-Pointer An aqueous sol-gel method for the preparation of doped TiO{sub 2} is being reported. Black-Right-Pointing-Pointer High photocatalytic activity and simplicity are the novelty of this work. Black-Right-Pointing-Pointer Enhanced activity is explained by the mechanism of trapping of charges.

• OSTI ID: 21612904
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Vol. 186; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
CATALYSIS
CHALCOGENIDES
CHEMISTRY
DOPED MATERIALS
ELECTROMAGNETIC RADIATION
IRON COMPOUNDS
IRON OXIDES
KINETICS
MATERIALS
MINERALS
NANOSTRUCTURES
OPTICAL PROPERTIES
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHOTOCATALYSIS
PHOTOCHEMISTRY
PHYSICAL PROPERTIES
RADIATIONS
RADIOACTIVE MATERIALS
RADIOACTIVE MINERALS
REACTION KINETICS
RECOMBINATION
RUTILE
SOL-GEL PROCESS
TITANIUM COMPOUNDS
TITANIUM OXIDES
TOXICITY
TRANSITION ELEMENT COMPOUNDS
VISIBLE RADIATION