A simple one-step thermal polymerization method was developed for synthesis of holey graphitic carbon nitride nanotubes,involving direci eating of mixtures of melamine and urea or melamine and cyanuric acid in specifi...A simple one-step thermal polymerization method was developed for synthesis of holey graphitic carbon nitride nanotubes,involving direci eating of mixtures of melamine and urea or melamine and cyanuric acid in specific mass ratios.Supramolecular structures formed betweer the precursor molecules guided nanotube formation.The porous and nanotubular structure of the nanotubes facilitated efficient charge carrier nigration and separation,thereby enhancing photocatalytic Hz production in 20 vol.%lactic acid under visible light irradiation.Nanotubes synthesized using melamine and urea in a 1:10 mass ratio(denoted herein as CN-MU nanotubes)exhibited a photocatalytic hydroger production rate of 1,073.6μmol·h^-1·^-g with Pt as the cocatalyst,a rate of 4.7 and 3.1 times higher than traditional Pt/g-CN4 photocatalysts prepared from graphitic carbon nitride(g-CN4)obtained by direct thermal polymerization of melamine or urea,respectively.On the basis of their outstanding performance for photocatalytic H2 production,it is envisaged that the holey g-C3N4 nanotubes will find widespread uptake in other areas,including photocatalytic CO2 reduction,dye-sensitized solar cells and photoelectrochemical sensors.展开更多
采用热聚合法结合溶胶法制备了TiO_(2)改性g-C_(3)N_(4)异质结光催化材料。采用透射电子显微镜(TEM)、X射线衍射仪(XRD)、紫外-可见漫反射光谱仪以及光致发光(PL)光谱仪等对其结构和性能进行了表征,研究了其对有机染料亚甲基蓝(MB)溶液...采用热聚合法结合溶胶法制备了TiO_(2)改性g-C_(3)N_(4)异质结光催化材料。采用透射电子显微镜(TEM)、X射线衍射仪(XRD)、紫外-可见漫反射光谱仪以及光致发光(PL)光谱仪等对其结构和性能进行了表征,研究了其对有机染料亚甲基蓝(MB)溶液的光催化降解活性。结果表明,TiO_(2)颗粒分布在g-C_(3)N_(4)的片层表面与其形成稳固的异质结结构,g-C_(3)N_(4)和TiO_(2)之间具有强烈的协同作用,提高了光催化材料在可见光区域的响应强度,并且有效地阻止了光催化材料中光生电子和空穴的复合,大大提高了催化剂的光催化反应效率。在可见光照射下,3.0 g g-C_(3)N_(4)制备的异质结复合材料对MB的降解率可达90.3%,与纯g-C_(3)N_(4)相比光催化性能有显著提高。循环测试表明该异质结光催化材料具有很好的光催化稳定性。展开更多
Novel TiO2/BiVO4 microfiber heterojunctions were constructed using cotton as biomorphic templates. The as-synthesized samples were characterized by scanning electron microscope, X-ray diffraction, X-ray photoelectron ...Novel TiO2/BiVO4 microfiber heterojunctions were constructed using cotton as biomorphic templates. The as-synthesized samples were characterized by scanning electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectra and photocatalytic experiment. The morphology of the as-synthesized TiO2/BiVO4 composites was consisted of a large quantity of microfiber structures with diameter from 2.5 gm to 5 μm, and the surface of samples became more coarse and compact with the increase of weight ratio of TiO2. The TiO2/BiVO4 samples with proper content （10.00wt%） showed the highest pho- tocatalytic degradation activity for methylene blue （MB） degradation among all the samples under visible light, and 88.58%MB could be degraded within 150 min. The enhancement of photocatalytic activity was mainly attributed to the formation of n-n heterojunction at the contact interface of TiO2 and BiVO4, which not only narrowed the band gap of BiVO4 for extending the absorption range of visible light, but also promoted the transfer of charge carriers across interface. A possible photodegradation mechanism of MB in the presence of TiO2/BiVO4 microfibrous photocatalyst was proposed.展开更多
Photocatalytic method has been intensively explored for Cr(VI)reduction owing to its efficient and environmentally friendly natures.In order to obtain a high efficiency in practical application,efficient photocatalyst...Photocatalytic method has been intensively explored for Cr(VI)reduction owing to its efficient and environmentally friendly natures.In order to obtain a high efficiency in practical application,efficient photocatalysts need to be developed.Here,ZnIn2S4/SnS2 with a three-dimensional(3D)heterostructure was prepared by a hydrothermal method and its photocatalytic performance in Cr(VI)reduction was investigated.When the mass ratio of SnS2 to ZnIn2S4 is 1:10,the ZnIn2S4/SnS2 composite exhibits the highest photocatalytic activity with 100%efficiency for Cr(VI)(50 mg/L)reduction within 70 min under visible-light irradiation,which is much higher than those of pure ZnIn2S4 and SnS2.The enhanced charge separation and the light absorption have been confirmed from the photoluminescence and UV-vis absorption spectra to be the two reasons for the increased activity towards photocatalytic Cr(VI)reduction.In addition,after three cycles of testing,no obvious degradation is observed with the 3D heterostructured ZnIn2S4/SnS2,which maintains a good photocatalytic stability.展开更多
An energetic-material （NAN3） deflagration method for preparing N- and Ti3＋-codoped TiO2 nanosheets （NT-TiO2） was developed. In this method, N radicals filled the crystal lattice, and Na clusters captured partial ...An energetic-material （NAN3） deflagration method for preparing N- and Ti3＋-codoped TiO2 nanosheets （NT-TiO2） was developed. In this method, N radicals filled the crystal lattice, and Na clusters captured partial O from TiO2. The deflagration process was fast and facile and can be completed within 〈 I s after ignition. The obtained NT-TiO2 exhibited rough surfaces with nanopits and nanoholes. The doping concentration can be regulated by controlling the NaN3 addition. The NT-TiO2 samples showed significant enhancements in the visible-light absorption and photoelectric response. The simultaneously produced N radicals and Na clusters from NaN3 deflagration served as N sources and reduction agents, respectively. Additionally, the high deflagration temperature/ pressure improved the reactivity of N radicals and Na dusters. Thus, the present NaN3 deflagration method was demonstrated as an ultrafast and effective approach to fabricate NT-TiO2 with a visible-light response. The proposed NaN3 deflagration method allows the ultrafast synthesis of new functional materials via the efficient deflagration of energetic materials.展开更多
基金The authors are grateful for the financial support from the National Key R&D Program of China(Nos.2018YFB1502002,2017YFA0206904,2017YFA0206900,and 2016YFB0600901)the National Natural Science Foundation of China(Nos.51825205,U1662U&51772305,51572270,21871279,and 21802154)+4 种基金the Beijing Natural Science Foundation(Nos.2191002,218207&and 2194089)the Beijing Municipal Science and Technology Project(No.Z181100005118007)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB17000000)the Royal Society-Newton Advanced Fellowship(No.NA170422)the International Partnership Program of Chinese Academy of Sciences(No.GJHZ1819)and the K.C.Wong Education Foundation.G.I.N.W.acknowledges funding support from the Energy Education Trust of New Zealand and the University of Auckland Faculty Research Development Fund.
文摘A simple one-step thermal polymerization method was developed for synthesis of holey graphitic carbon nitride nanotubes,involving direci eating of mixtures of melamine and urea or melamine and cyanuric acid in specific mass ratios.Supramolecular structures formed betweer the precursor molecules guided nanotube formation.The porous and nanotubular structure of the nanotubes facilitated efficient charge carrier nigration and separation,thereby enhancing photocatalytic Hz production in 20 vol.%lactic acid under visible light irradiation.Nanotubes synthesized using melamine and urea in a 1:10 mass ratio(denoted herein as CN-MU nanotubes)exhibited a photocatalytic hydroger production rate of 1,073.6μmol·h^-1·^-g with Pt as the cocatalyst,a rate of 4.7 and 3.1 times higher than traditional Pt/g-CN4 photocatalysts prepared from graphitic carbon nitride(g-CN4)obtained by direct thermal polymerization of melamine or urea,respectively.On the basis of their outstanding performance for photocatalytic H2 production,it is envisaged that the holey g-C3N4 nanotubes will find widespread uptake in other areas,including photocatalytic CO2 reduction,dye-sensitized solar cells and photoelectrochemical sensors.
文摘采用热聚合法结合溶胶法制备了TiO_(2)改性g-C_(3)N_(4)异质结光催化材料。采用透射电子显微镜(TEM)、X射线衍射仪(XRD)、紫外-可见漫反射光谱仪以及光致发光(PL)光谱仪等对其结构和性能进行了表征,研究了其对有机染料亚甲基蓝(MB)溶液的光催化降解活性。结果表明,TiO_(2)颗粒分布在g-C_(3)N_(4)的片层表面与其形成稳固的异质结结构,g-C_(3)N_(4)和TiO_(2)之间具有强烈的协同作用,提高了光催化材料在可见光区域的响应强度,并且有效地阻止了光催化材料中光生电子和空穴的复合,大大提高了催化剂的光催化反应效率。在可见光照射下,3.0 g g-C_(3)N_(4)制备的异质结复合材料对MB的降解率可达90.3%,与纯g-C_(3)N_(4)相比光催化性能有显著提高。循环测试表明该异质结光催化材料具有很好的光催化稳定性。
基金This work was supported by Program Funded by Sha.anxi Department （No.2013JK0690）, the Scientific Research Provincial Education Fundamental Research Funds of Xianyang Normal University （No. 14XSYK011, No.12XSYK025）, Shaanxi Province Natural Science Foundation （No.2015JQ5188）.
文摘Novel TiO2/BiVO4 microfiber heterojunctions were constructed using cotton as biomorphic templates. The as-synthesized samples were characterized by scanning electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectra and photocatalytic experiment. The morphology of the as-synthesized TiO2/BiVO4 composites was consisted of a large quantity of microfiber structures with diameter from 2.5 gm to 5 μm, and the surface of samples became more coarse and compact with the increase of weight ratio of TiO2. The TiO2/BiVO4 samples with proper content （10.00wt%） showed the highest pho- tocatalytic degradation activity for methylene blue （MB） degradation among all the samples under visible light, and 88.58%MB could be degraded within 150 min. The enhancement of photocatalytic activity was mainly attributed to the formation of n-n heterojunction at the contact interface of TiO2 and BiVO4, which not only narrowed the band gap of BiVO4 for extending the absorption range of visible light, but also promoted the transfer of charge carriers across interface. A possible photodegradation mechanism of MB in the presence of TiO2/BiVO4 microfibrous photocatalyst was proposed.
基金the support of the National Natural Science Foundation of China (51702087 and 21673066)~~
文摘Photocatalytic method has been intensively explored for Cr(VI)reduction owing to its efficient and environmentally friendly natures.In order to obtain a high efficiency in practical application,efficient photocatalysts need to be developed.Here,ZnIn2S4/SnS2 with a three-dimensional(3D)heterostructure was prepared by a hydrothermal method and its photocatalytic performance in Cr(VI)reduction was investigated.When the mass ratio of SnS2 to ZnIn2S4 is 1:10,the ZnIn2S4/SnS2 composite exhibits the highest photocatalytic activity with 100%efficiency for Cr(VI)(50 mg/L)reduction within 70 min under visible-light irradiation,which is much higher than those of pure ZnIn2S4 and SnS2.The enhanced charge separation and the light absorption have been confirmed from the photoluminescence and UV-vis absorption spectra to be the two reasons for the increased activity towards photocatalytic Cr(VI)reduction.In addition,after three cycles of testing,no obvious degradation is observed with the 3D heterostructured ZnIn2S4/SnS2,which maintains a good photocatalytic stability.
文摘An energetic-material （NAN3） deflagration method for preparing N- and Ti3＋-codoped TiO2 nanosheets （NT-TiO2） was developed. In this method, N radicals filled the crystal lattice, and Na clusters captured partial O from TiO2. The deflagration process was fast and facile and can be completed within 〈 I s after ignition. The obtained NT-TiO2 exhibited rough surfaces with nanopits and nanoholes. The doping concentration can be regulated by controlling the NaN3 addition. The NT-TiO2 samples showed significant enhancements in the visible-light absorption and photoelectric response. The simultaneously produced N radicals and Na clusters from NaN3 deflagration served as N sources and reduction agents, respectively. Additionally, the high deflagration temperature/ pressure improved the reactivity of N radicals and Na dusters. Thus, the present NaN3 deflagration method was demonstrated as an ultrafast and effective approach to fabricate NT-TiO2 with a visible-light response. The proposed NaN3 deflagration method allows the ultrafast synthesis of new functional materials via the efficient deflagration of energetic materials.
