TY - JOUR
T1 - Enhanced photocatalytic activity of rutile TiO2 prepared by anodic oxidation in a high concentration sulfuric acid electrolyte
AU - Masahashi, N.
AU - Mizukoshi, Y.
AU - Semboshi, S.
AU - Ohtsu, N.
N1 - Funding Information:
The authors wish to thank Prof. Hanada for his valuable comments and encouragement to continue this study. We wish to acknowledge Ms. Y. Matsuda and Mr. S. Sugiyama from IMR, Tohoku University for the sample preparation, Mr. M. Yamane at Kitami Institute of Technology for XPS experiments and Mr. K. Hatanaka from Keyence Co., Ltd. for laser microscope observations. The authors are grateful to Dr. T. Moroishi, Mr. Y. Mitani, and Mr. R. Ozawa from Tig Co. Ltd. for helpful discussions. One of the authors (N.M.) received a Grant-in-Aid for Scientific Research (A) (No. 17206070) from the Ministry of Education, Culture, Sports, Science, and Technology, Japan.
PY - 2009/7/25
Y1 - 2009/7/25
N2 - The photocatalytic characteristics of TiO2 prepared by anodic oxidation in an electrolyte with a high concentration of sulfuric acid were investigated, focusing on the crystallinity and microstructure of the oxide. The predominant phase in the anodic oxide changes from anatase to rutile with the sulfuric acid concentration; the change appears when this concentration is 0.4 M. Nanosized pores appear in the oxide when the concentration of sulfuric acid is greater than 0.1 M, and the surface area increases with the sulfuric acid concentration. Structural analysis revealed that the inhomogeneous lattice strain in both anatase and rutile is reduced to almost zero, implying that the oxide contains a small number of recombination sites; as a result, the probability of the extinction of the photogenerated charges is low. The methylene blue (MB) bleaching test shows that the photocatalytic activity improves as the concentration of sulfuric acid increases and that the characteristics of rutile are better than those of anatase. It is concluded that rutile-structured TiO2 exhibits the best photocatalytic activity among the investigated oxides, due to its high crystallinity and porous microstructure.
AB - The photocatalytic characteristics of TiO2 prepared by anodic oxidation in an electrolyte with a high concentration of sulfuric acid were investigated, focusing on the crystallinity and microstructure of the oxide. The predominant phase in the anodic oxide changes from anatase to rutile with the sulfuric acid concentration; the change appears when this concentration is 0.4 M. Nanosized pores appear in the oxide when the concentration of sulfuric acid is greater than 0.1 M, and the surface area increases with the sulfuric acid concentration. Structural analysis revealed that the inhomogeneous lattice strain in both anatase and rutile is reduced to almost zero, implying that the oxide contains a small number of recombination sites; as a result, the probability of the extinction of the photogenerated charges is low. The methylene blue (MB) bleaching test shows that the photocatalytic activity improves as the concentration of sulfuric acid increases and that the characteristics of rutile are better than those of anatase. It is concluded that rutile-structured TiO2 exhibits the best photocatalytic activity among the investigated oxides, due to its high crystallinity and porous microstructure.
KW - Anodic oxidation
KW - Crystallinity
KW - Photocatalysis
KW - Surface area
KW - Titanium oxide
UR - http://www.scopus.com/inward/record.url?scp=65749094836&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=65749094836&partnerID=8YFLogxK
U2 - 10.1016/j.apcatb.2009.03.011
DO - 10.1016/j.apcatb.2009.03.011
M3 - Article
AN - SCOPUS:65749094836
VL - 90
SP - 255
EP - 261
JO - Applied Catalysis B: Environmental
JF - Applied Catalysis B: Environmental
SN - 0926-3373
IS - 1-2
ER -