The fabrication of well defined hierarchical structures of anatase TiO_(2) with a high percentage of reactive facets is of great importance and challenging.Hierarchically flower-like TiO_(2) superstructures(HFTS)self-...The fabrication of well defined hierarchical structures of anatase TiO_(2) with a high percentage of reactive facets is of great importance and challenging.Hierarchically flower-like TiO_(2) superstructures(HFTS)self-assembled from anatase TiO_(2) nanosheets with exposed{001}facets(up to 87%)were synthesized by a simple alcohothermal strategy in a HF-H_(2)O-C_(2)H_(5)OH mixed solution using titanate nanotubes as precursor.The samples were characterized by X-ray diffraction,scanning electron microscopy,transmission electron microscopy,and N2 adsorption-desorption isotherms.The photocatalytic activity was evaluated by the photocatalytic oxidation decomposition of acetone in air and methyl orange in aqueous solution under UV illumination.The photocatalytic activity of HFTS was much higher than that of commercial Degussa P25 and tabular-shaped anatase TiO_(2) obtained using pure water as the synthesis medium.The enhancement in photocatalytic activity was related to several factors,including the hierarchically porous structure,exposed{001}facets,and increased light harvesting ability.The HFTS was also of interest for use in solar cells,photocatalytic H_(2) production,optoelectronic devices,sensors,and catalysis.展开更多
Ultrathin TiO_(2)nanosheets with coexposed{001}/{101}facets have attracted considerable attention because of their high photocatalytic activity.However,the charge-separated states in the TiO_(2)nanosheets must be exte...Ultrathin TiO_(2)nanosheets with coexposed{001}/{101}facets have attracted considerable attention because of their high photocatalytic activity.However,the charge-separated states in the TiO_(2)nanosheets must be extended to further enhance their photocatalytic activity for H_(2)evolution.Herein,we present a successful attempt to selectively dope lanthanide ions into the{101}facets of ultrathin TiO_(2)nanosheets with coexposed{001}/{101}facets through a facile one-step solvothermal method.The lanthanide doping slightly extended the light-harvesting region and markedly improved the charge-separated states of the TiO_(2)nanosheets as evidenced by UV-vis absorption and steady-state/transient photoluminescence spectra.Upon simulated sunlight irradiation,we observed a 4.2-fold enhancement in the photocatalytic H_(2)evolution activity of optimal Yb^(3+)-doped TiO_(2)nanosheets compared to that of their undoped counterparts.Furthermore,when Pt nanoparticles were used as cocatalysts to reduce the H_(2)overpotential in this system,the photocatalytic activity enhancement factor increased to 8.5.By combining these results with those of control experiments,we confirmed that the extended charge-separated states play the main role in the enhancement of the photocatalytic H_(2)evolution activity of lanthanide-doped TiO_(2)nanosheets with coexposed{001}/{101}facets.展开更多
A sample of sulfated anatase TiO2 with high‐energy(001)facets(TiO2‐001)was prepared by a simple one‐step hydrothermal route using SO42-as a morphology‐controlling agent.After doping ceria,Ce/TiO2‐001 was used as ...A sample of sulfated anatase TiO2 with high‐energy(001)facets(TiO2‐001)was prepared by a simple one‐step hydrothermal route using SO42-as a morphology‐controlling agent.After doping ceria,Ce/TiO2‐001 was used as the catalyst for selective catalytic reduction(SCR)of NO with NH3.Compared with Ce/P25(Degussa P25 TiO2)and Ce/P25‐S(sulfated P25)catalysts,Ce/TiO2‐001 was more suitable for medium‐and high‐temperature SCR of NO due to the high surface area,sulfation,and the excellent properties of the active‐energy(001)facets.All of these facilitated the generation of abundant acidity,chemisorbed oxygen,and activated NOx‐adsorption species,which were the important factors for the SCR reaction.展开更多
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
This study investigated the positive effect of surface modification with ozone on the photocatalytic performance of anatase TiO2 with dominated（001） facets for toluene degradation.The performance of photocatalyst wa...This study investigated the positive effect of surface modification with ozone on the photocatalytic performance of anatase TiO2 with dominated（001） facets for toluene degradation.The performance of photocatalyst was tested on a home-made volatile organic compounds degradation system. The ozone modification, toluene adsorption and degradation mechanism were established by a combination of various characterization methods, in situ diffuse reflectance infrared fourier transform spectroscopy, and density functional theory calculation.The surface modification with ozone can significantly enhance the photocatalytic degradation performance for toluene. The abundant unsaturated coordinated 5 c-Ti sites on（001）facets act as the adsorption sites for ozone. The formed Ti–O bonds reacted with H2O to generate a large amount of isolated Ti5 c-OH which act as the adsorption sites for toluene,and thus significantly increase the adsorption capacity for toluene. The outstanding photocatalytic performance of ozone-modified TiO2 is due to its high adsorption ability for toluene and the abundant surface hydroxyl groups, which produce very reactive OH·radicals under irradiation. Furthermore, the O2 generated via ozone dissociation could combine with the photogenerated electrons to form superoxide radicals which are also conductive to the toluene degradation.展开更多
Reactive facets of heterogeneous photocatalysts play an important role during the water photolysis process since they afford the active sites/planes for the photoredox splitting of water or loading of co-catalysts.Rec...Reactive facets of heterogeneous photocatalysts play an important role during the water photolysis process since they afford the active sites/planes for the photoredox splitting of water or loading of co-catalysts.Recent studies indicated that the facets also play additional roles during charge separation.Therefore,identifying and exploring how the reactive facets facilitate the reactivity is considered to be a crucial step for developing high-performance photocatalysts for solar to chemical energy conversion.展开更多
{001}facets dominated single crystalline anatase TiO_(2) nanosheet array(TNSA)was synthe-sized through an optimized organic solvothermal route on uorine-doped tin oxide substrate.The field emission scanning electron m...{001}facets dominated single crystalline anatase TiO_(2) nanosheet array(TNSA)was synthe-sized through an optimized organic solvothermal route on uorine-doped tin oxide substrate.The field emission scanning electron microscopy images and X-ray diffraction patterns re-vealed that the{001}synthesized facets dominated TNSA exhibited much higher orientation than that synthesized by hydrothermal route.The TNSAs were loaded with Pt nanoparti-cles in uniformly size by using a photodecomposition method,which were further con rmed by high resolution transmission electron microscopy(HRTEM).The HRTEM images also revealed that Pt nanoparticles preferred to deposit on{001}facets.With loading of Pt nanoparticles,the optical absorbance was significantly enhanced,while the photolumines-cence(PL)was inhibited.The photocatalytic activity of TNSA was signi cantly improved by Pt loading and reached the maximum with optimal amount of Pt loading.The optimal amount of Pt on{001}facets is far less than that on TiO_(2) nanoparticles,which may be attributed to the specific atom structure of reactive{001}facets.展开更多
基金supported by the National Natural Science Foundation of China(50625208,20773097,and 20877061)the National Basic Research Program of China(973Program,2007CB613302and2009CB939704)Fundamental Research Funds for the Central Universities(2010-YB-01)
文摘The fabrication of well defined hierarchical structures of anatase TiO_(2) with a high percentage of reactive facets is of great importance and challenging.Hierarchically flower-like TiO_(2) superstructures(HFTS)self-assembled from anatase TiO_(2) nanosheets with exposed{001}facets(up to 87%)were synthesized by a simple alcohothermal strategy in a HF-H_(2)O-C_(2)H_(5)OH mixed solution using titanate nanotubes as precursor.The samples were characterized by X-ray diffraction,scanning electron microscopy,transmission electron microscopy,and N2 adsorption-desorption isotherms.The photocatalytic activity was evaluated by the photocatalytic oxidation decomposition of acetone in air and methyl orange in aqueous solution under UV illumination.The photocatalytic activity of HFTS was much higher than that of commercial Degussa P25 and tabular-shaped anatase TiO_(2) obtained using pure water as the synthesis medium.The enhancement in photocatalytic activity was related to several factors,including the hierarchically porous structure,exposed{001}facets,and increased light harvesting ability.The HFTS was also of interest for use in solar cells,photocatalytic H_(2) production,optoelectronic devices,sensors,and catalysis.
文摘Ultrathin TiO_(2)nanosheets with coexposed{001}/{101}facets have attracted considerable attention because of their high photocatalytic activity.However,the charge-separated states in the TiO_(2)nanosheets must be extended to further enhance their photocatalytic activity for H_(2)evolution.Herein,we present a successful attempt to selectively dope lanthanide ions into the{101}facets of ultrathin TiO_(2)nanosheets with coexposed{001}/{101}facets through a facile one-step solvothermal method.The lanthanide doping slightly extended the light-harvesting region and markedly improved the charge-separated states of the TiO_(2)nanosheets as evidenced by UV-vis absorption and steady-state/transient photoluminescence spectra.Upon simulated sunlight irradiation,we observed a 4.2-fold enhancement in the photocatalytic H_(2)evolution activity of optimal Yb^(3+)-doped TiO_(2)nanosheets compared to that of their undoped counterparts.Furthermore,when Pt nanoparticles were used as cocatalysts to reduce the H_(2)overpotential in this system,the photocatalytic activity enhancement factor increased to 8.5.By combining these results with those of control experiments,we confirmed that the extended charge-separated states play the main role in the enhancement of the photocatalytic H_(2)evolution activity of lanthanide-doped TiO_(2)nanosheets with coexposed{001}/{101}facets.
基金supported by the National Key R&D Program of China(2016YFC0204100)the Zhejiang Provincial "151" Talents Program+1 种基金the Program for Zhejiang Leading Team of S&T Innovation(2013TD07)the Changjiang Scholar Incentive Program(2009)~~
文摘A sample of sulfated anatase TiO2 with high‐energy(001)facets(TiO2‐001)was prepared by a simple one‐step hydrothermal route using SO42-as a morphology‐controlling agent.After doping ceria,Ce/TiO2‐001 was used as the catalyst for selective catalytic reduction(SCR)of NO with NH3.Compared with Ce/P25(Degussa P25 TiO2)and Ce/P25‐S(sulfated P25)catalysts,Ce/TiO2‐001 was more suitable for medium‐and high‐temperature SCR of NO due to the high surface area,sulfation,and the excellent properties of the active‐energy(001)facets.All of these facilitated the generation of abundant acidity,chemisorbed oxygen,and activated NOx‐adsorption species,which were the important factors for the SCR reaction.
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 National Natural Science Foundation of China (U1632273, 21673214,U1732272, U1832165).
文摘This study investigated the positive effect of surface modification with ozone on the photocatalytic performance of anatase TiO2 with dominated（001） facets for toluene degradation.The performance of photocatalyst was tested on a home-made volatile organic compounds degradation system. The ozone modification, toluene adsorption and degradation mechanism were established by a combination of various characterization methods, in situ diffuse reflectance infrared fourier transform spectroscopy, and density functional theory calculation.The surface modification with ozone can significantly enhance the photocatalytic degradation performance for toluene. The abundant unsaturated coordinated 5 c-Ti sites on（001）facets act as the adsorption sites for ozone. The formed Ti–O bonds reacted with H2O to generate a large amount of isolated Ti5 c-OH which act as the adsorption sites for toluene,and thus significantly increase the adsorption capacity for toluene. The outstanding photocatalytic performance of ozone-modified TiO2 is due to its high adsorption ability for toluene and the abundant surface hydroxyl groups, which produce very reactive OH·radicals under irradiation. Furthermore, the O2 generated via ozone dissociation could combine with the photogenerated electrons to form superoxide radicals which are also conductive to the toluene degradation.
文摘Reactive facets of heterogeneous photocatalysts play an important role during the water photolysis process since they afford the active sites/planes for the photoredox splitting of water or loading of co-catalysts.Recent studies indicated that the facets also play additional roles during charge separation.Therefore,identifying and exploring how the reactive facets facilitate the reactivity is considered to be a crucial step for developing high-performance photocatalysts for solar to chemical energy conversion.
基金This work is supported by the National Basic Research Program of China(No.2012CB9222000).
文摘{001}facets dominated single crystalline anatase TiO_(2) nanosheet array(TNSA)was synthe-sized through an optimized organic solvothermal route on uorine-doped tin oxide substrate.The field emission scanning electron microscopy images and X-ray diffraction patterns re-vealed that the{001}synthesized facets dominated TNSA exhibited much higher orientation than that synthesized by hydrothermal route.The TNSAs were loaded with Pt nanoparti-cles in uniformly size by using a photodecomposition method,which were further con rmed by high resolution transmission electron microscopy(HRTEM).The HRTEM images also revealed that Pt nanoparticles preferred to deposit on{001}facets.With loading of Pt nanoparticles,the optical absorbance was significantly enhanced,while the photolumines-cence(PL)was inhibited.The photocatalytic activity of TNSA was signi cantly improved by Pt loading and reached the maximum with optimal amount of Pt loading.The optimal amount of Pt on{001}facets is far less than that on TiO_(2) nanoparticles,which may be attributed to the specific atom structure of reactive{001}facets.
