TY - JOUR
T1 - Halloysite-TiO2 nanocomposites
T2 - Synthesis, characterization and photocatalytic activity
AU - Papoulis, Dimitrios
AU - Komarneni, Sridhar
AU - Panagiotaras, Dionisios
AU - Stathatos, Elias
AU - Toli, Despina
AU - Christoforidis, Konstantinos C.
AU - Fernández-García, Marcos
AU - Li, Huihui
AU - Yin, Shu
AU - Sato, Tsugio
AU - Katsuki, Hiroaki
N1 - Funding Information:
The authors would like to thank Applied Minerals Inc., New York, USA, for their cooperation and for providing us with halloysite samples. The authors wish to thank Dr. Drakopoulos of the Foundation for Research and Technology-Hellas (FORTH) Institute of Chemical Engineering and High Temperature Chemical Processes (ICE/HT) Rio-Patras, Greece, for his help with SEM micrographs. The research leading to these results has received funding from the European Union's Seventh Framework Programme ( FP7/2007-2013 ) under grant agreement n° 253445. Dr. Christoforidis K.C. acknowledges Marie Curie Action–Intra-European Fellowship (FP7-PEOPLE-2009-IEF-253445) for a Post-doctoral Fellowship.
PY - 2013/3/7
Y1 - 2013/3/7
N2 - Two halloysite-TiO2 nanocomposites were prepared with two different tubular halloysite clays by depositing anatase-TiO2 on the halloysite surfaces using titanium isopropoxide under hydrothermal treatment at 180°C. The nanocomposites were characterized by X-Ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), attenuated total reflection using Fourier transform infrared spectroscopy (ATR-FTIR), absorption properties by UV-vis spectroscopy and N2 specific surface area (SSA) analysis by BET method. Good dispersion of 3-10nm TiO2 particles on halloysite external surfaces was achieved in both the halloysite-TiO2 nanocomposites and ATR-FTIR results showed the formation of hydrogen bonding between TiO2 and the outer surfaces of halloysite tubes. After treating with TiO2, both halloysite samples largely showed interparticle mesopores of about 5.7nm. However, the macropores of halloysite (lumen or central hole in halloysite tubes) were not detected probably as a result of plugging of the lumens in halloysite tubes by TiO2 nanoparticles. These nanocomposites were tested for their photocatalytic activities in decomposing NOx gas and toluene. The halloysite-titania samples showed significantly higher activity in decomposing NOx gas under visible-light irradiation (λ>510nm) and UV-visible light irradiation (λ>290nm) compared to that of the standard commercial titania photocatalyst, P25. In addition, composite photocatalyst showed larger catalytic activity either under sunlight or pure UV irradiation in decomposing toluene compared to the commercial titania, P25. Our experimental data suggest that the enhanced photocatalytic activity is related with the good dispersion of the TiO2 nanocrystals on the surface of the clay minerals.
AB - Two halloysite-TiO2 nanocomposites were prepared with two different tubular halloysite clays by depositing anatase-TiO2 on the halloysite surfaces using titanium isopropoxide under hydrothermal treatment at 180°C. The nanocomposites were characterized by X-Ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), attenuated total reflection using Fourier transform infrared spectroscopy (ATR-FTIR), absorption properties by UV-vis spectroscopy and N2 specific surface area (SSA) analysis by BET method. Good dispersion of 3-10nm TiO2 particles on halloysite external surfaces was achieved in both the halloysite-TiO2 nanocomposites and ATR-FTIR results showed the formation of hydrogen bonding between TiO2 and the outer surfaces of halloysite tubes. After treating with TiO2, both halloysite samples largely showed interparticle mesopores of about 5.7nm. However, the macropores of halloysite (lumen or central hole in halloysite tubes) were not detected probably as a result of plugging of the lumens in halloysite tubes by TiO2 nanoparticles. These nanocomposites were tested for their photocatalytic activities in decomposing NOx gas and toluene. The halloysite-titania samples showed significantly higher activity in decomposing NOx gas under visible-light irradiation (λ>510nm) and UV-visible light irradiation (λ>290nm) compared to that of the standard commercial titania photocatalyst, P25. In addition, composite photocatalyst showed larger catalytic activity either under sunlight or pure UV irradiation in decomposing toluene compared to the commercial titania, P25. Our experimental data suggest that the enhanced photocatalytic activity is related with the good dispersion of the TiO2 nanocrystals on the surface of the clay minerals.
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U2 - 10.1016/j.apcatb.2012.12.012
DO - 10.1016/j.apcatb.2012.12.012
M3 - Article
AN - SCOPUS:84872422731
SN - 0926-3373
VL - 132-133
SP - 416
EP - 422
JO - Applied Catalysis B: Environmental
JF - Applied Catalysis B: Environmental
ER -