表面负载型g-C_3N_4/TiO_2复合催化剂的制备及可见光催化还原Cr(Ⅵ)的性能研究
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摘要
采用热聚合-溶剂热法得到表面负载型g-C_3N_4/TiO_2复合材料,其结构组成、形貌和光电性质通过XRD、TEM、HRTEM、FT-IR、BET和UV-vis测试分析.结果表明TiO_2纳米小颗粒负载于微米级片状g-C_3N_4表面,形成稳定的g-C_3N_4/TiO_2固-固异质结构,扩大了光响应范围、显著提高光生载流子的分离效率.在可见光催化还原水中Cr(Ⅵ)的过程中,g-C_3N_4的质量百分含量是影响光催化活性的重要因素,g-C_3N_4/TiO_2-C具有最高的光催化活性和良好的稳定性.依据实验结果和光电流响应实验给出光催化反应机理.
Highly efficient visible-light-driven heterojunction photocatalysts,surface modification of TiO_2 coupled with graphitic g-C_3N_4 microsheets,have been synthesized by thermal polymerization-solvothermal method.The structures,compositions,Brunauer-Emmett-Teller(BET)specific surface areas and optical properties of the as-synthesized products were characterized by X-ray diffraction(XRD),transmission electron microscopy(TEM),high resolution transmission electron microscopy(HRTEM),N_2 adsorption-desorption analysis,Fourier transform infrared(FTIR)and UV-vis diffuse reflectance spectra.The results showed TiO_2 nanoparticles with a uniform diameter of about 10 nm dispersed uniformly on the surface of graphitic g-C_3N_4 microsheets,expanded the light response range,and significantly improved the separation efficiency of h+-e-.It was found that the as-synthesized g-C_3N_4/TiO_2 nanocomposite with a suitable g-C_3N_4 content(e.g.,42.2 mass% g-C_3N_4)not only exhibited extraordinary superior photocatalytic activity,but also had good photocatalytic stability.Based on the experimental results,apossible enhanced photocatalytic mechanism of g-C_3N_4/TiO_2 heterojunction photocatalysts was proposed.The factors affecting the photocatalytic activity were also discussed based on the result of structure analysis,optical and photoelectric characteristics,and photocatalytic reactions.
Highly efficient visible-light-driven heterojunction photocatalysts,surface modification of TiO_2 coupled with graphitic g-C_3N_4 microsheets,have been synthesized by thermal polymerization-solvothermal method.The structures,compositions,Brunauer-Emmett-Teller(BET)specific surface areas and optical properties of the as-synthesized products were characterized by X-ray diffraction(XRD),transmission electron microscopy(TEM),high resolution transmission electron microscopy(HRTEM),N_2 adsorption-desorption analysis,Fourier transform infrared(FTIR)and UV-vis diffuse reflectance spectra.The results showed TiO_2 nanoparticles with a uniform diameter of about 10 nm dispersed uniformly on the surface of graphitic g-C_3N_4 microsheets,expanded the light response range,and significantly improved the separation efficiency of h+-e-.It was found that the as-synthesized g-C_3N_4/TiO_2 nanocomposite with a suitable g-C_3N_4 content(e.g.,42.2 mass% g-C_3N_4)not only exhibited extraordinary superior photocatalytic activity,but also had good photocatalytic stability.Based on the experimental results,apossible enhanced photocatalytic mechanism of g-C_3N_4/TiO_2 heterojunction photocatalysts was proposed.The factors affecting the photocatalytic activity were also discussed based on the result of structure analysis,optical and photoelectric characteristics,and photocatalytic reactions.
引文
[1]Xiang Q,Cheng B,Yu J.Graphene-based photocatalysts for solar-fuel gen-eration[J].Angewandte Chemie International Edition,2015,54:11350-11366.
[2]Hiroshi Y,Yukiyasu Y,Hideo T,Heterogeneous photocatalytic recuction of dichromate on n-type semiconductor catalysts[J].Nature,1979,282:817-818.
[3]Steven N.Frank,Allen J.Bard,Heterogeneous photocatalytic oxidation of cyanide and sulfite in aqueous solutions at semiconductor powders[J].The Journal of Physical Chemistry,1977,81:1484-1488.
[4]Yuan J L,Gao Q Z,Li X,et al.Novel 3-D nanoporous graphitic-C3N4nanosheets with heterostructured modification for efficient visible-light photocatalytic hydrogen production[J].Rsc Advances,2014,4(94):52332.
[5]Dong S Y,Feng J L,Fan M H,et al.Recent developments in heterogeneous photocatalytic water treatment using visible light-responsive photocatalysts:a review[J].Rsc Advances,2015,5:14610-14630.
[6]Cao S,Low J,Yu J.et al.Polymeric photocatalysts based on graphitic carbon nitride[J].Advanced Materials,2015,27:2150-2176.
[7]李静谊,斯琴高娃,刘丽娜,等.紫外和可见光照射下金属离子对TiO2/膨润土光催化降解罗丹明B的影响[J].内蒙古大学学报:自然科学版,2008,39(1):24-29.
[8]Song Y,Chen G,Yu Y G,et al.A new oxynitride-based solid state Z-scheme photocatalytic system for efficient Cr(VI)reduction and water oxidation[J].Applied Catalysis B Environmental,2016,183:176-184.
[9]Wang N,Zhu L H,Deng K J,et al.Visible light photocatalytic reduction of Cr(VI)on TiO2in suit modified with small molecular weight organic acids[J].Applied Catalysis B:Environmental,2010,95:400-407.
[10]Zhang Y C,Li J,Zhang M,et al.Size-tunable hydrothermal synthesis of SnS2nanocrystals with high performance in visible light-driven photocatalytic reduction of aqueous Cr(VI)[J].Environmental Science&Technology,2011,45:9324-9331.
[11]Zhang Y C,Li J,Xu H Y.One-step in situ solvothermal synthesis of SnS2/TiO2nanocomposites with high performance in visible light-driven photocatalytic reduction of aqueous Cr(VI)[J].Applied Catalysis B:Environmental,2012,123-124:18-26.
[12]Li J,Wang T X,D X H.Preparation of visible light-driven SnS2/TiO2 nanocomposite photocatalyst for the reduction of aqueous Cr(VI)[J].Separation and Purification Technology,2012,101:11-17.
[13]Sun Y,Cheng H,Gao S,et al.Freestanding tin disulfide single-layers realizing efficient visible-light water splitting[J].Angewandte Chemie International Edition,2012,51:8727-8731.
[14]Liu H,Su Y,Chen P,et al.Microwave-assisted solvothermal synthesis of 3Dcarnation-like SnS2nanostructures with high visible light photocatalytic activity[J].Journal of Molecular Catalysis A,2013,378:285-292.
[15]Wang J,Li X,Li X,et al.Mesoporous yolk-shell SnS2-TiO2visible photocatalysts with enhanced activity and durability in Cr(VI)reduction[J].Nanoscale,2013,5:1876-1881.
[16]Hao R,Wang G H,Tang H,et al.Template-free preparation of macro/mesoporous g-C3N4/TiO2heterojunction photocatalysts with enhanced visible light photocatalytic activity[J].Applied Catalysis B:Environmental,2016,187:47-58.
[17]Tang H,Chang S F,Jiang L Y,et al.Novel spindle-shaped nanoporous TiO2coupled graphitic g-C3N4nanosheets with enhanced visible-light photocatalytic activity[J].Ceramics International,2016,42(16):18443-18452.
[18]Ma T,Wu J,Mi Y,et al.Novel Z-Scheme g-C3N4/C@Bi2MoO6composite with enhanced visible-light photocatalytic activity for b-naphthol degradation[J].Separation and Purification Technology,2017,183:54-65.
[19]Jiang D,Yu H,Yu H B.Modified g-C3N4/TiO2nanosheets/ZnO ternary facet coupled heterojunction for photocatalytic degradation of p-toluenesulfonic acid(p-TSA)under visible light[J].Physica E,2017,85:1-6.
[20]Chen X,Zhou B H,Yang S L.In situ construction of an SnO2/g-C3N4 heterojunction for enhanced visible-light photocatalytic activity[J].RSC Advances,2015,5:68953-68963.
[21]Wang C,Zhu W S,Xu Y H.Preparation of TiO2/g-C3N4composites and their application in photocatalytic oxidative desulfurization[J].Ceramics International,2014,40:11627-11635.
[22]Li K,Gao S M,Wang Q Y,et al.In-situ-reduced synthesis of Ti 3+self-doped TiO2/g-C3N4heterojunctions with high photocatalytic performance under LED light irradiation[J].ACS Applied Materials&Interfaces,2015,7:9023-9030.
[23]Gu L,Wang J Y,Zou Z J,et al.Graphitic-C3N4-hybridized TiO2nanosheets with reactive{001}facets to enhance the UV-and visible-light photocatalytic activity[J].Journal of Hazardous Materia,2014,268:216-223.
[24]Chang F,Zhang J,Xie Y C,et al.Fabrication,characterization,and photocatalytic performance of exfoliated gC3N4-TiO2hybrids[J].Applied Surface Science,2014,311:574-581.
[25]Liao M H,Hsu C H,Chen D H.Preparation and properties of amorphous titania-coated zinc oxide nanoparticles[J].Journal of Solid State Chemistry,2006,179:2020-2026.
[26]Wang Y,Shi R,Lin J,Y.Zhu,Enhancement of photocurrent and photocatalytic activity of ZnO hybridized with graphite-like C3N4[J].Energy Environmental science,2011,4:2922-2929.
[27]Martin D J,Qiu K P,Shevlin S A,et al.Highly efficient photocatalytic H2evolution from water using visible light and structure-controlled graphitic carbon nitride[J].Angewandte Chemie,2014,126:9394-9399,
[28]Yu J G,Wang S H,Low J X,et al.Enhanced photocatalytic performance of direct Z-scheme g-C3N4-TiO2photocatalysts for the decomposition of formaldehyde in air[J].Physical Chemistry Chemical Physics,2013,15:16883-1890.
[29]Bojdys M J,Muller J O,Antonietti M,et al.Ionothermal synthesis of crystalline,condensed,graphitic carbon nitride[J].Chemistry-A European Journal,2008,14:8177-8182.
[30]Ilias P,Nadia T,Tatiana G,et al.Photocatalytic activity of modified g-C3N4/TiO2nanocomposites for NOx Removal[J].Catalysis Today,2017,280:37-44.
[31]Chen T,Song C,Shi W,et al.In-situ fabrication of CuS/g-C3N4 nanocomposites with enhanced photocatalytic H2-production activity via photoinduced interfacial charge transfer[J].International Journal of Hydrogen Energy,2017:1-10.
[32]Luo J,Zhou X,Ma L,et al.Enhancing visible light photocatalytic activity of direct Z-scheme SnS2/Ag3PO4heterojunction photocatalysts[J].Materials Research Bulletin,2016,81:16-26.
[33]Zhou D,Chen Z,Yang Q,et al.In-situ constructionofall-solid-stateZ-schemeg-C3N4/TiO2nanotube arrays photocatalyst with enhanced visible-light-induced properties[J].Solar EnergyMaterials&SolarCells,2016,157:399-405
[34]Chen X F,Wei J,Hou R J,et al.Growth of g-C3N4on mesoporous TiO2spheres with high photocatalytic activity under visible light irradiation[J].Applied Catalysis B:Environmental,2016,188:342-350.
[2]Hiroshi Y,Yukiyasu Y,Hideo T,Heterogeneous photocatalytic recuction of dichromate on n-type semiconductor catalysts[J].Nature,1979,282:817-818.
[3]Steven N.Frank,Allen J.Bard,Heterogeneous photocatalytic oxidation of cyanide and sulfite in aqueous solutions at semiconductor powders[J].The Journal of Physical Chemistry,1977,81:1484-1488.
[4]Yuan J L,Gao Q Z,Li X,et al.Novel 3-D nanoporous graphitic-C3N4nanosheets with heterostructured modification for efficient visible-light photocatalytic hydrogen production[J].Rsc Advances,2014,4(94):52332.
[5]Dong S Y,Feng J L,Fan M H,et al.Recent developments in heterogeneous photocatalytic water treatment using visible light-responsive photocatalysts:a review[J].Rsc Advances,2015,5:14610-14630.
[6]Cao S,Low J,Yu J.et al.Polymeric photocatalysts based on graphitic carbon nitride[J].Advanced Materials,2015,27:2150-2176.
[7]李静谊,斯琴高娃,刘丽娜,等.紫外和可见光照射下金属离子对TiO2/膨润土光催化降解罗丹明B的影响[J].内蒙古大学学报:自然科学版,2008,39(1):24-29.
[8]Song Y,Chen G,Yu Y G,et al.A new oxynitride-based solid state Z-scheme photocatalytic system for efficient Cr(VI)reduction and water oxidation[J].Applied Catalysis B Environmental,2016,183:176-184.
[9]Wang N,Zhu L H,Deng K J,et al.Visible light photocatalytic reduction of Cr(VI)on TiO2in suit modified with small molecular weight organic acids[J].Applied Catalysis B:Environmental,2010,95:400-407.
[10]Zhang Y C,Li J,Zhang M,et al.Size-tunable hydrothermal synthesis of SnS2nanocrystals with high performance in visible light-driven photocatalytic reduction of aqueous Cr(VI)[J].Environmental Science&Technology,2011,45:9324-9331.
[11]Zhang Y C,Li J,Xu H Y.One-step in situ solvothermal synthesis of SnS2/TiO2nanocomposites with high performance in visible light-driven photocatalytic reduction of aqueous Cr(VI)[J].Applied Catalysis B:Environmental,2012,123-124:18-26.
[12]Li J,Wang T X,D X H.Preparation of visible light-driven SnS2/TiO2 nanocomposite photocatalyst for the reduction of aqueous Cr(VI)[J].Separation and Purification Technology,2012,101:11-17.
[13]Sun Y,Cheng H,Gao S,et al.Freestanding tin disulfide single-layers realizing efficient visible-light water splitting[J].Angewandte Chemie International Edition,2012,51:8727-8731.
[14]Liu H,Su Y,Chen P,et al.Microwave-assisted solvothermal synthesis of 3Dcarnation-like SnS2nanostructures with high visible light photocatalytic activity[J].Journal of Molecular Catalysis A,2013,378:285-292.
[15]Wang J,Li X,Li X,et al.Mesoporous yolk-shell SnS2-TiO2visible photocatalysts with enhanced activity and durability in Cr(VI)reduction[J].Nanoscale,2013,5:1876-1881.
[16]Hao R,Wang G H,Tang H,et al.Template-free preparation of macro/mesoporous g-C3N4/TiO2heterojunction photocatalysts with enhanced visible light photocatalytic activity[J].Applied Catalysis B:Environmental,2016,187:47-58.
[17]Tang H,Chang S F,Jiang L Y,et al.Novel spindle-shaped nanoporous TiO2coupled graphitic g-C3N4nanosheets with enhanced visible-light photocatalytic activity[J].Ceramics International,2016,42(16):18443-18452.
[18]Ma T,Wu J,Mi Y,et al.Novel Z-Scheme g-C3N4/C@Bi2MoO6composite with enhanced visible-light photocatalytic activity for b-naphthol degradation[J].Separation and Purification Technology,2017,183:54-65.
[19]Jiang D,Yu H,Yu H B.Modified g-C3N4/TiO2nanosheets/ZnO ternary facet coupled heterojunction for photocatalytic degradation of p-toluenesulfonic acid(p-TSA)under visible light[J].Physica E,2017,85:1-6.
[20]Chen X,Zhou B H,Yang S L.In situ construction of an SnO2/g-C3N4 heterojunction for enhanced visible-light photocatalytic activity[J].RSC Advances,2015,5:68953-68963.
[21]Wang C,Zhu W S,Xu Y H.Preparation of TiO2/g-C3N4composites and their application in photocatalytic oxidative desulfurization[J].Ceramics International,2014,40:11627-11635.
[22]Li K,Gao S M,Wang Q Y,et al.In-situ-reduced synthesis of Ti 3+self-doped TiO2/g-C3N4heterojunctions with high photocatalytic performance under LED light irradiation[J].ACS Applied Materials&Interfaces,2015,7:9023-9030.
[23]Gu L,Wang J Y,Zou Z J,et al.Graphitic-C3N4-hybridized TiO2nanosheets with reactive{001}facets to enhance the UV-and visible-light photocatalytic activity[J].Journal of Hazardous Materia,2014,268:216-223.
[24]Chang F,Zhang J,Xie Y C,et al.Fabrication,characterization,and photocatalytic performance of exfoliated gC3N4-TiO2hybrids[J].Applied Surface Science,2014,311:574-581.
[25]Liao M H,Hsu C H,Chen D H.Preparation and properties of amorphous titania-coated zinc oxide nanoparticles[J].Journal of Solid State Chemistry,2006,179:2020-2026.
[26]Wang Y,Shi R,Lin J,Y.Zhu,Enhancement of photocurrent and photocatalytic activity of ZnO hybridized with graphite-like C3N4[J].Energy Environmental science,2011,4:2922-2929.
[27]Martin D J,Qiu K P,Shevlin S A,et al.Highly efficient photocatalytic H2evolution from water using visible light and structure-controlled graphitic carbon nitride[J].Angewandte Chemie,2014,126:9394-9399,
[28]Yu J G,Wang S H,Low J X,et al.Enhanced photocatalytic performance of direct Z-scheme g-C3N4-TiO2photocatalysts for the decomposition of formaldehyde in air[J].Physical Chemistry Chemical Physics,2013,15:16883-1890.
[29]Bojdys M J,Muller J O,Antonietti M,et al.Ionothermal synthesis of crystalline,condensed,graphitic carbon nitride[J].Chemistry-A European Journal,2008,14:8177-8182.
[30]Ilias P,Nadia T,Tatiana G,et al.Photocatalytic activity of modified g-C3N4/TiO2nanocomposites for NOx Removal[J].Catalysis Today,2017,280:37-44.
[31]Chen T,Song C,Shi W,et al.In-situ fabrication of CuS/g-C3N4 nanocomposites with enhanced photocatalytic H2-production activity via photoinduced interfacial charge transfer[J].International Journal of Hydrogen Energy,2017:1-10.
[32]Luo J,Zhou X,Ma L,et al.Enhancing visible light photocatalytic activity of direct Z-scheme SnS2/Ag3PO4heterojunction photocatalysts[J].Materials Research Bulletin,2016,81:16-26.
[33]Zhou D,Chen Z,Yang Q,et al.In-situ constructionofall-solid-stateZ-schemeg-C3N4/TiO2nanotube arrays photocatalyst with enhanced visible-light-induced properties[J].Solar EnergyMaterials&SolarCells,2016,157:399-405
[34]Chen X F,Wei J,Hou R J,et al.Growth of g-C3N4on mesoporous TiO2spheres with high photocatalytic activity under visible light irradiation[J].Applied Catalysis B:Environmental,2016,188:342-350.
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