The role of crystal phase in determining photocatalytic activity of nitrogen doped TiO2.
Two series of nitrogen doped TiO(2) samples with different ratios of anatase to rutile phases were prepared by milling the mixture of P25 TiO(2) and C(6)H(12)N(4) in air and gaseous NH(3) atmosphere, respectively. Compared to air, NH(3) atmosphere plays an important role in delaying the crystallite transformation from anatase to rutile in the mechanochemical reaction of TiO(2) and C(6)H(12)N(4). In contrast to the previously reported results for pure TiO(2), it is found that nitrogen doped TiO(2) with higher content of rutile phase demonstrates higher photocatalytic activity in photodegrading pollutant Rhodamine B under both UV light and visible light irradiation (lambda>420 nm), and the amount of the surface-adsorbed water and hydroxyl groups on nitrogen doped TiO(2) have little correlations with their crystallite phases (anatase or rutile) and photocatalytic activity. The more abundant surface states characterized by photoluminescence spectroscopy together with the lowered valence band maximum of rutile TiO(2) by nitrogen doping are considered as the key factors for the higher activity of nitrogen doped TiO(2) with higher content of rutile phase.
Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016, China.
Gang
G
Liu
Xuewen
X
Wang
Zhigang
Z
Chen
Hui-Ming
HM
Cheng
Gao Qing Max
GQ
Lu
D002384:Catalysis; D003460:Crystallization; D004785:Environmental Pollutants / Q000528:radiation effects; D008027:Light; D009584:Nitrogen; D010777:Photochemistry; D014025:Titanium / Q000737:chemistry*; D014466:Ultraviolet Rays
D004785:Environmental Pollutants; C009495:titanium dioxide; D014025:Titanium; D009584:Nitrogen