TY - JOUR
T1 - Effect of N-doping on the photocatalytic activity of sol-gel TiO 2
AU - Nolan, Nicholas T.
AU - Synnott, Damian W.
AU - Seery, Michael K.
AU - Hinder, Steven J.
AU - Van Wassenhoven, Axel
AU - Pillai, Suresh C.
N1 - Funding Information:
The authors wish to thank Science Foundation Ireland (SFI grant number 10/US/I1822 ) for supporting this investigation under the US-Ireland R&D partnership programme, CREST and Focas for lab and office facilities and equipment. The authors would also like to thank Dr. John Colreavy for reviewing the paper and providing valuable comments and Michael Whelan for providing the scanning electron microscopy images. The authors would like to acknowledge Enterprise Ireland ( CFTD/06/IT/326 and ARE/2008/0005 ) and Environmental Protection Agency (EPA) Ireland for funding.
PY - 2012/4/15
Y1 - 2012/4/15
N2 - In order to study the visible light photocatalytic activity of nitrogen doped titanium dioxide, the interaction between nitrogen dopant sources and titania precursors during sol-gel synthesis is investigated. N-TiO 2 was synthesised using the sol-gel method using 1,3-diaminopropane as a nitrogen source. Samples were annealed several temperatures and the percentage of rutile present determined by X-ray diffraction to be 0% (500°C), 46% (600°C), and 94% (700°C). The reducing amounts of anatase at higher temperatures are studied using FTIR, which suggests the absence of any polymeric chains formed by the chelating agents, which would normally extend anatase-to-rutile transformation temperatures. Differential scanning calorimetry shows that crystalliation occurs before 500°C, providing the crystalline form determined by XRD at 500°C. Increased temperature also resulted in diminished visible light absorption capability, with only the 500°C sample showing significant absorption in the visible region. XPS studies revealed that nitrogen remained within the TiO 2 lattice at higher temperatures. Consequent with the reduced visible light absorption capacity, photocatalytic activity also reduced with increased annealing temperature. Degradation kinetics of methylene blue, irradiated with a 60W house-bulb, resulted in first order degradation rates constants of 0.40×10 -2, 0.19×10 -2, and 0.22×10 -2min -1 for 500, 600, and 700°C respectively. Degradation of Degussa P25 was minimal under the same conditions, and that of undoped TiO 2 was 0.02×10 -2min -1. Similarly, using 4-chlorophenol under solar irradiation conditions, the N-doped sample at 500°C substantially out-performed the undoped sample. These results are discussed in the context of the effect of increasing temperature on the nature of the band gap.
AB - In order to study the visible light photocatalytic activity of nitrogen doped titanium dioxide, the interaction between nitrogen dopant sources and titania precursors during sol-gel synthesis is investigated. N-TiO 2 was synthesised using the sol-gel method using 1,3-diaminopropane as a nitrogen source. Samples were annealed several temperatures and the percentage of rutile present determined by X-ray diffraction to be 0% (500°C), 46% (600°C), and 94% (700°C). The reducing amounts of anatase at higher temperatures are studied using FTIR, which suggests the absence of any polymeric chains formed by the chelating agents, which would normally extend anatase-to-rutile transformation temperatures. Differential scanning calorimetry shows that crystalliation occurs before 500°C, providing the crystalline form determined by XRD at 500°C. Increased temperature also resulted in diminished visible light absorption capability, with only the 500°C sample showing significant absorption in the visible region. XPS studies revealed that nitrogen remained within the TiO 2 lattice at higher temperatures. Consequent with the reduced visible light absorption capacity, photocatalytic activity also reduced with increased annealing temperature. Degradation kinetics of methylene blue, irradiated with a 60W house-bulb, resulted in first order degradation rates constants of 0.40×10 -2, 0.19×10 -2, and 0.22×10 -2min -1 for 500, 600, and 700°C respectively. Degradation of Degussa P25 was minimal under the same conditions, and that of undoped TiO 2 was 0.02×10 -2min -1. Similarly, using 4-chlorophenol under solar irradiation conditions, the N-doped sample at 500°C substantially out-performed the undoped sample. These results are discussed in the context of the effect of increasing temperature on the nature of the band gap.
KW - Band gap widening
KW - Degussa p25
KW - Mechanism of doping
KW - N-doping
KW - Photocatalytic activity
KW - Semiconductor photocatalysis
KW - Sol-gel and TiO
KW - Visible light activity
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U2 - 10.1016/j.jhazmat.2011.08.074
DO - 10.1016/j.jhazmat.2011.08.074
M3 - Article
C2 - 21963170
AN - SCOPUS:84858298133
SN - 0304-3894
VL - 211-212
SP - 88
EP - 94
JO - Journal of Hazardous Materials
JF - Journal of Hazardous Materials
ER -