Response surface methodology(RSM)was employed to optimize the control parameters of TiO_(2)/graphene with exposed{001}facets during synthesis,and its enhanced photocatalytic activities were evaluated in the photodegra...Response surface methodology(RSM)was employed to optimize the control parameters of TiO_(2)/graphene with exposed{001}facets during synthesis,and its enhanced photocatalytic activities were evaluated in the photodegradation of toluene.Experimental results were in good agreement with the predicted results obtained using RSM with a correlation coefficient(R^(2))of 0.9345.When 22.06 mg of graphite oxide(GO)and 2.09 mL of hydrofluoric acid(HF)were added and a hydrothermal time of 28 h was used,a maximum efficiency in the degradation of toluene was achieved.X-ray diffraction(XRD),transmission electron microscopy(TEM),and scanning electron microscopy(SEM)were employed to characterize the obtained hybrid photocatalyst.The electron transferred between Ti and C retarded the combination of electron–hole pairs and hastened the transferring of electrons,which enhanced the photocatalytic activity.展开更多
By means of first-principles calculations based on the ab initio pseudopotential andplane wave basis, we present self-consistent molecular dynamic calculations to determine a cleanTiO_2 crystal (001) surface geometry ...By means of first-principles calculations based on the ab initio pseudopotential andplane wave basis, we present self-consistent molecular dynamic calculations to determine a cleanTiO_2 crystal (001) surface geometry and surface electronic states structure. All calculations wereperformed for both rutile and anatase phases. Using a total energy minimization strategy, weacquired the general inward relaxations. The s-like surface states just above the lower valenceband at (001) surfaces both in the rutile and anatase phases are found. The band bending effectoccurs both in rutile and anatase (001) surfaces. It reduces the band gap by ac. 0.4 eV in rutileand ac. 0.8 eV in anatase, elevating the Fermi energy levels. Besides the band bending of thevalence band, surface states also lie near the bottom of the conduction band. The lower surfaceenergy of anatase makes nanocrystalline TiO_2 is often in the anatase phase below a critical size.Our results are in good agreement with the previous work and experimental data.展开更多
基金This work was financially supported by the National Key R&D Program of China(No.2017YFA0205004)the Anhui Initiative in Quantum Information Technologies(AHY090000)+1 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(XDB36020200)the National Natural Science Foundation of China(No.11620101003,No.11904349,and No.21972129).
基金supported by the National Natural Science Foundation of China(Nos.21406164,21466035 and 51203111)the National Basic Research Program of China("973"Program,Nos.2012CB720100 and 2014CB239300)
文摘Response surface methodology(RSM)was employed to optimize the control parameters of TiO_(2)/graphene with exposed{001}facets during synthesis,and its enhanced photocatalytic activities were evaluated in the photodegradation of toluene.Experimental results were in good agreement with the predicted results obtained using RSM with a correlation coefficient(R^(2))of 0.9345.When 22.06 mg of graphite oxide(GO)and 2.09 mL of hydrofluoric acid(HF)were added and a hydrothermal time of 28 h was used,a maximum efficiency in the degradation of toluene was achieved.X-ray diffraction(XRD),transmission electron microscopy(TEM),and scanning electron microscopy(SEM)were employed to characterize the obtained hybrid photocatalyst.The electron transferred between Ti and C retarded the combination of electron–hole pairs and hastened the transferring of electrons,which enhanced the photocatalytic activity.
基金The project supported by National Key Project of China for Basic Research on Photovoltaic Cell (No. G2000028200)
文摘By means of first-principles calculations based on the ab initio pseudopotential andplane wave basis, we present self-consistent molecular dynamic calculations to determine a cleanTiO_2 crystal (001) surface geometry and surface electronic states structure. All calculations wereperformed for both rutile and anatase phases. Using a total energy minimization strategy, weacquired the general inward relaxations. The s-like surface states just above the lower valenceband at (001) surfaces both in the rutile and anatase phases are found. The band bending effectoccurs both in rutile and anatase (001) surfaces. It reduces the band gap by ac. 0.4 eV in rutileand ac. 0.8 eV in anatase, elevating the Fermi energy levels. Besides the band bending of thevalence band, surface states also lie near the bottom of the conduction band. The lower surfaceenergy of anatase makes nanocrystalline TiO_2 is often in the anatase phase below a critical size.Our results are in good agreement with the previous work and experimental data.
