N-F-codoped TiO2 （NFTO） photocatalysts were synthesized by a simple sol-gel process with tetrabutyl titanate （Ti（OBu）4 ） as the precursor of TiO 2 and ammonium fluoride （NH4 F） as the source of N and F.The syn...N-F-codoped TiO2 （NFTO） photocatalysts were synthesized by a simple sol-gel process with tetrabutyl titanate （Ti（OBu）4 ） as the precursor of TiO 2 and ammonium fluoride （NH4 F） as the source of N and F.The synthesized photocatalysts were investigated by X- ray diffraction （XRD）,X-ray photoelectron spectroscopy （XPS）,ultraviolet-visible diffuse reflectance spectroscopy （UV-Vis DRS） and photodegradation reaction tests of 4-chlorophenol under visible light irradiation to understand the relationship between the structure of NFTO catalyst and corresponding photocatalytic activity.The crystal phase and particle size of catalysts were found to be largely affected by the calcination temperature.In addition,N-F-codoping could inhibit phase transition of TiO2 from anatase to rutile.The presence of N and F atoms in the lattice of TiO2 is responsible for the visible light catalytic activity.In UV-Vis DRS tests,the spectrum of NFTO exhibited red shift compared with Degussa P25 and the band gap was reduced to around 2.92 eV.Under optimal calcination temperature and dopant concentration conditions,the NFTO photocatalyst exhibited the highest activity in the photodegradation reaction tests of 4-chlorophenol under visible light irradiation with a degradation rate of 75.84%.Besides,the 5-recycle test showed that NFTO photocatalyst could be reused and its activity kept stable under visible light irradiation.展开更多
Wave front solutions and the minimal wave speeds of Noges-Field systems for B-Z chemical reaction are discussed. The sufficient and necessary conditions for the existence of travelling wave front solutions are obtaine...Wave front solutions and the minimal wave speeds of Noges-Field systems for B-Z chemical reaction are discussed. The sufficient and necessary conditions for the existence of travelling wave front solutions are obtained under some conditions. The approximants obtained in [-4] are proved in theory.展开更多
基金supported by the Scienceand Technology Project of Education Commission of Chongqing of China(No.KJ110709)the Key Science Project of Ministry of Education of China(No.2008119)+1 种基金the Colleges and Universities Innovation Team Project of Chongqing of China(No.KJTD201020)the Scienceand Technology Project of Engineering Research Centre for Waste Oil,Ministry of Education of China(No.FYKJ2009012)
文摘N-F-codoped TiO2 （NFTO） photocatalysts were synthesized by a simple sol-gel process with tetrabutyl titanate （Ti（OBu）4 ） as the precursor of TiO 2 and ammonium fluoride （NH4 F） as the source of N and F.The synthesized photocatalysts were investigated by X- ray diffraction （XRD）,X-ray photoelectron spectroscopy （XPS）,ultraviolet-visible diffuse reflectance spectroscopy （UV-Vis DRS） and photodegradation reaction tests of 4-chlorophenol under visible light irradiation to understand the relationship between the structure of NFTO catalyst and corresponding photocatalytic activity.The crystal phase and particle size of catalysts were found to be largely affected by the calcination temperature.In addition,N-F-codoping could inhibit phase transition of TiO2 from anatase to rutile.The presence of N and F atoms in the lattice of TiO2 is responsible for the visible light catalytic activity.In UV-Vis DRS tests,the spectrum of NFTO exhibited red shift compared with Degussa P25 and the band gap was reduced to around 2.92 eV.Under optimal calcination temperature and dopant concentration conditions,the NFTO photocatalyst exhibited the highest activity in the photodegradation reaction tests of 4-chlorophenol under visible light irradiation with a degradation rate of 75.84%.Besides,the 5-recycle test showed that NFTO photocatalyst could be reused and its activity kept stable under visible light irradiation.
文摘Wave front solutions and the minimal wave speeds of Noges-Field systems for B-Z chemical reaction are discussed. The sufficient and necessary conditions for the existence of travelling wave front solutions are obtained under some conditions. The approximants obtained in [-4] are proved in theory.
