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1.
在H2O2-HF 的乙醇-水混合溶液中, 通过水热处理碳氮化钛(TiCN)制备了碳、氮共掺杂TiO2 空心球(CNTH). 用X 射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、X 射线光电子能谱(XPS)和紫外-可见(UV-Vis)吸收光谱表征了所制备的样品. 在可见光(λ≥400 nm)照射下, 通过降解甲基蓝检测了碳、氮共掺杂TiO2空心球的光催化活性. 结果表明, 源于TiCN中的部分碳和氮原子原位掺入了TiO2的晶格中, 部分碳掺入TiO2点阵的间隙中. 该材料在整个可见光区展示了增强的可见光吸收, 其带边明显红移. 光催化研究表明在强可见光吸收和独特的空心球结构的协同作用下, 碳、氮共掺杂TiO2空心球展示了比P25更高的可见光光催化活性.  相似文献   

2.
张爱平  张进治 《无机化学学报》2009,25(11):2040-2047
采用水热合成法, 制备出Eu、Gd和Er掺杂的BiVO4复合光催化剂,并采用X射线衍射、X射线光电子谱、扫描电子显微镜和紫外-可见漫反射光谱技术对其进行分析表征。通过可见光下降解水溶液中甲基橙分子来考察其光催化性能,结果显示掺杂的复合光催化剂活性都强于纯的BiVO4,对掺杂复合光催化剂的催化活性增强机理进行了讨论和描述。  相似文献   

3.
利用溶胶-凝胶和溶剂热联合技术制备了Pr-N-P三元掺杂锐钛矿TiO2(PrNPTO)纳米片,并采用X射线衍射、透射电镜、N2吸附、X射线光电子能谱、UV-vis吸收谱和光致荧光光谱分析技术对其进行了表征.当Pr掺杂量为1.75wt%,焙烧温度为550℃时,制得的PrNPTO在可见和紫外光下光催化降解亚甲基蓝(MB)活性最佳.在模拟太阳光照射下,PrNPTO也表现出优越的光催化降解4-氯酚性能(kapp=3.90×10-2min-1),优于未掺杂、单掺杂和双掺杂TiO2样品,其光活性是P25TiO2的3.33倍(kapp=1.17×10-2min-1).PrNPTO光活性的提高归因于Pr-N-P三元掺杂增强了紫外和可见光吸收,降低了光生载流子复合,增加了表面羟基以及改善了表面织构特性.在模拟太阳光照射下,PrNPTO光催化效率高且光催化性能稳定,适合于环境净化领域的实际应用.  相似文献   

4.
采用新的化学溶液法,通过不同体积的钛酸四异丙酯的2-乙二醇单乙醚溶液与一定浓度的H2O2水溶液直接反应并对生成的钛过氧化配合物进行焙烧,制备了一系列TiO2光催化剂. 表征发现,所得TiO2样品为金红石和锐钛矿的纳米复合晶体,改变2-乙二醇单乙醚的体积可实现金红石相比例在0~96%广范围的调变.与商业二氧化钛P-25相比,所得的TiO2紫外-可见光吸收谱出现明显红移,间隙能降低, 在可见光照射下,该样品对亚甲基蓝有良好的降解活性. 当2-乙二醇单乙醚的添加量为5 ml时,所得样品体相中金红石相比例接近50%,其光催化活性和吸附性能最好,可分别是P-25的3倍和5倍. 拉曼光谱结合X射线衍射等表征结果表明,该样品的表面仅含少量的金红石相. TiO2纳米复合晶表面晶相的组成和分布对其光催化降解亚甲基蓝的活性及其吸附能力有直接的影响. 另外,TiO2纳米复合晶的缺陷浓度也是增强其光吸收能力,提高其可见光光催化活性的原因之一.  相似文献   

5.
使用L-半胱氨酸作为连接剂, 利用硼氢化钠原位还原预先吸附在介孔氧化亚铜表面的氯金酸根离子,得到了Au/Cu2O异质结构. 应用X射线粉末衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、X射线光电子能谱(XPS)、紫外-可见(UV-Vis)光谱和N2物理吸附等手段对催化剂进行表征, 并以λ>400 nm的可见光作为光源, 评价了该催化剂光催化降解亚甲基蓝(MB)的活性. 实验结果表明, 直径为4 nm的金颗粒完好地负载在介孔氧化亚铜的表面, 并且介孔氧化亚铜的细微结构与孔径均未发生变化. 研究表明, 以乙醇作为反应溶剂有效抑制了AuCl4-与Cu2O之间的氧化还原反应, 从而有利于氧化亚铜介孔结构的保持及金颗粒的原位还原. 光催化降解亚甲基蓝的结果表明, Au/Cu2O异质结构的光催化活性比纯氧化亚铜光催化活性有明显提高. 推测其光催化性能提高的主要原因如下: 一方面, 金颗粒良好的导电性有利于氧化亚铜表面电子的快速转移, 实现电子-空穴分离; 另一方面, 金颗粒可能存在的表面等离子共振现象加速了光生电子的产生.  相似文献   

6.
通过水热法制备稀土Pr掺杂Bi2WO6三维花状微球,利用XRD、SEM、N2吸附-脱附、紫外-可见吸收光谱和光致发光光谱对所制备的光催化材料进行表征。通过降解亚甲基蓝评价样品的光催化活性。结果表明,1.0% Pr-Bi2WO6样品的可见光催化活性最佳,降解率达到95%。Pr掺杂提高了催化剂的可见光吸收性能并且能够束缚光生电子使得电子空穴对有效分离从而获得强氧化物质。对其光催化降解做出了合理的解释。  相似文献   

7.
通过水热法制备稀土Pr掺杂Bi2WO6三维花状微球,利用XRD、SEM、N2吸附-脱附、紫外-可见吸收光谱和光致发光光谱对所制备的光催化材料进行表征。通过降解亚甲基蓝评价样品的光催化活性。结果表明,1.0% Pr-Bi2WO6样品的可见光催化活性最佳,降解率达到95%。Pr掺杂提高了催化剂的可见光吸收性能并且能够束缚光生电子使得电子空穴对有效分离从而获得强氧化物质。对其光催化降解做出了合理的解释。  相似文献   

8.
采用超声波辐射法制备了具有介孔结构的高浓度氮掺杂TiO2纳米晶(N/TiO2).采用N2物理吸附、X射线粉末衍射、X射线光电子能谱、透射电镜、光致发光谱和紫外-可见漫反射光谱等手段对N/TiO2进行了表征.以波长为400~660nm的可见光为光源,以水体污染物邻苯二甲酸二甲酯为降解对象,考察了不同制备方法对N/TiO2光催化性能的影响.结果表明,超声波辐射使氮掺杂浓度提高了2.2倍,该法制备的N/TiO2同时具有较好的介孔结构,表现了更高的光催化降解邻苯二甲酸二甲酯的活性.其活性提高的主要原因是N/TiO2含有更高浓度的氮和对可见光具有更强的吸收能力.  相似文献   

9.
马明远  李佑稷  陈伟  李雷勇 《催化学报》2010,31(10):1221-1226
 以钛酸丁酯为前驱体, 封堵的火山岩为载体, 通过超临界 CO2 辅助制备了 TiO2 外负载火山岩复合体, 并将其用于光催化降解亚甲基蓝反应, 考察了溶液 pH 值及催化剂浓度对反应性能的影响. 结果表明, TiO2 外负载火山岩复合体的光催化性能优于纯 TiO2 和 TiO2 体负载火山岩复合体. 这是由于外负载复合体对亚甲基蓝的高吸附性、小晶粒尺寸的 TiO2 颗粒以及吸附和光催化降解间的协同效应. 亚甲基蓝浓度为 1.5 mg/L, 溶液 pH 为 8, 催化剂浓度为 6.8 mg/L 时, 外负载 TiO2 火山岩复合体上亚甲基蓝降解速率最高, 且使用后的催化剂仍具有高的光催化活性.  相似文献   

10.
利用原位生长法制备了一系列不同AgBr含量的AgBr@ZnO复合光催化剂,采用X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、紫外-可见漫反射吸收光谱(UV-Vis)等手段对所制备的光催化剂进行了表征,并考察了AgBr@ZnO在可见光下光催化降解亚甲基蓝溶液的光催化性能。研究表明,AgBr均匀负载在ZnO表面,且复合光催化剂表现出比纯ZnO更高的光催化活性。当复合AgBr含量为10%时,所制备的复合光催化剂的光催化活性最佳,光反应240 min后对MB的降解率可达82.3%。所制备的复合光催化剂可见光下降解亚甲基蓝遵循一级反应动力学。  相似文献   

11.
CdS/石墨烯纳米复合物的可见光催化效率和抗光腐蚀行为   总被引:1,自引:0,他引:1  
严佳佳  王坤  许晖  钱静  刘巍  杨兴旺  李华明 《催化学报》2013,34(10):1876-1882
制备了一系列CdS纳米晶/石墨烯(CdS/GR)复合物,并在可见光照条件下评价了其光催化降解亚甲基蓝的光催化效率和抗光腐蚀行为. 研究表明,石墨烯的引入加速了CdS纳米晶(NCs)光生电子的迁移速率,抑制了其光生电子-空穴的复合,有效改善了其光催化降解有机污染物的性能. CdS/GR复合物中的石墨烯含量显著影响其光催化效率,其中石墨烯含量为4.6%的光催化剂效率最高,其光电流是CdS NCs的2.3倍. 利用光电化学和X射线衍射技术进一步证实,石墨烯的引入抑制了CdS NCs光腐蚀的发生,提高了CdS/GR复合物的光催化稳定性.  相似文献   

12.
CuFe_2O_4-TiO_2/graphene nanocomposites have been prepared via a one-step hydrothermal method,and the as-prepared CuFe_2O_4-TiO_2/graphene was characterized by X-ray powder diffraction,Raman spectroscopy,scanning electron microscopy and transmission electron microscopy.The transmission electron microscopy demonstrated that CuFe_2O_4-TiO_2 nanoparticles were successfully dispersed on the graphene sheets.Photocatalytic activity of nanocomposites was evaluated in terms of degradation of methylene blue(MB) dye solution under visible light radiation.Results showed that the photocatalytic efficiency of CuFe_2O_4-TiO_2/graphene nanocomposites was higher than its individual pure oxides(CuFe_2O_4 or TiO_2) and TiO_2/graphene.The enhancing photocatalytic activity performance of the CuFe_2O_4-TiO_2/graphene nanocomposites may attributed to the mutual effect between the Cu Fe_2O_4,Ti O_2 nanoparticles and the graphene sheets.Moreover,Cu Fe_2O_4 nanoparticles have excellent magnetic property,which makes the CuFe_2O_4-TiO_2/graphene heteroarchitecture magnetically recyclable in a suspension system.  相似文献   

13.
BiOBr/graphene nanocomposites were synthesized by a green single-step microwave strategy and characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. The photocatalytic activity of the as-prepared BiOBr nanoplates and BiOBr/graphene nanocomposites for the photodegeneration of organic dyes in aqueous solution under visible light irradiation was investigated. The results show that BiOBr/graphene nanocomposites have a higher photocatalytic activity than bare BiOBr nanoplates.  相似文献   

14.
This study shows a facile approach for the preparation of CeO2 nanoparticles decorated with porous nitrogen‐doped graphene (NG) nanosheets for effective photocatalytic degradation of methylene blue (MB). NG nanosheets were first synthesized using a hydrothermal method and then nitrogen‐doped graphene‐cerium oxide (NG‐CeO2) was prepared through mixing of cerium nitrate with different concentrations of NG under ultrasonication followed by hydrothermal treatment. The synthesized nanocomposites were characterized using X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and field emission scanning electron microscopy (FE‐SEM). The photocatalytic activity of the synthesized nanocomposites was analyzed against MB dye. Results showed that the nanocomposites of NG‐CeO2 have an average particle size of 20 nm. The as‐prepared NG‐CeO2 nanocomposites exhibited outstanding photocatalytic activity for dye degradation under visible light irradiation, which could be attributed to synergistic effects between the NG nanosheets and CeO2. The quantum of photodegradation increases with the increase of the NG content in the nanocomposites.  相似文献   

15.
CuS-graphene oxide/TiO2 composites were prepared using a sol-gel method to improve the photocatalytic performance of the photocatalyst. The composites were characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis, and transmission electron microscopy. The photocatalytic activities were examined by the degradation of methylene blue (MB) under visible-light irradiation. The photodegradation of MB under visible-light irradiation reached 90.1% after 120 min. The kinetics of MB degradation was plotted alongside the values calculated from the Langmuir-Hinshelwood equation. The CuS-graphene oxide/TiO2 sample prepared using 0.2 mol of TiO2 showed the best photocatalytic activity. This was attributed to a cooperative reaction as a result of increased photoabsorption by graphene oxide and an increased photocatalytic effect by CuS.  相似文献   

16.
In this article, novel Ag–ZnO/g-C3N4/GO ternary nanocomposites were prepared via co-precipitation method by 1%w Ag, 50% w g-C3N4, 10% w GO concentration and applied in dynamic membranes. The characteristics of Ag–ZnO/g-C3N4/GO nanocomposite were evaluated by various techniques such as X-ray diffraction, field emission scanning electron microscopy, energy dispersive X-ray map, transmission electron microscopy, X-ray photoelectron spectroscopy, photocatalyst. The photocatalytic degradation of methylene blue was investigated under visible light. The photocatalytic efficiency of 93.43% for methylene blue degradation was obtained for Ag–ZnO/g-C3N4/GO nanocomposite after 50 min of irradiation, which was remarkably higher than that of pure ZnO, bare g-C3N4, Ag–ZnO, and Ag–ZnO/g-C3N4 at the same irradiation time. Likewise, in self-forming and pre-coated membranes, ternary nanocomposites can play a vital role in the membrane surface properties, as well as their decolorization performance. The rejection of methylene blue was 30% in pure polyethersulfone membrane, while the photocatalytic degradation of methylene blue in Ag–ZnO/g-C3N4/GO nanocomposites was 88.46% and 98.86% after 10 and 15 min of irradiation in both self-forming and pre-coated dynamic membranes, respectively. Experimental results show that the dynamic membrane possesses a higher ability for degradation of MB in a shorter period of time than the static system.  相似文献   

17.
Magnetite zinc oxide (MZ) (Fe3O4/ZnO) with different ratios of reduced graphene oxide (rGO) was synthesized using the solid-state method. The structural and optical properties of the nanocomposites were analyzed using transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), ultraviolet–visible diffuse reflectance spectroscopy (UV–Vis/DRS), and photoluminescence (PL) spectrophotometry. In particular, the analyses show higher photocatalytic movement for crystalline nanocomposite (MZG) than MZ and ZnO nanoparticles. The photocatalytic degradation of methylene blue (MB) with crystalline ZnO for 1.5 h under visible light was 12%. By contrast, the photocatalytic activity for MZG was more than 98.5%. The superior photocatalytic activity of the crystalline nanocomposite was detected to be due to the synergistic effect between magnetite and zinc oxide in the presence of reduced graphene oxide. Moreover, the fabricated nanocomposite had high electron–hole stability. The crystalline nanocomposite was stable when the material was used several times.  相似文献   

18.
A series of composites containing hexagonal tungsten trioxide (h-WO3) and reduced graphene oxide (rGO) sheets are synthesized via a modified one-step hydrothermal route without assisted additive. The composites are characterized by transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and UV-vis absorption spectroscopy. The new procedure made it possible to increase the reduction degree of GO. Based on the evidence presented hexagonal WO3 grows on the surface of graphene through chemical interactions with the surface. The visible-light photocatalytic degradation of methylene blue shows that the h-WO3/rGO composites exhibit superior photocatalytic performance of 96% with a maximum degradation rate achieved under visible-light irradiation for 6 h. The speculations concerning the mechanism of photocatalytic reactions are discussed. The improved photocatalytic activity can be accounted for by the increased adsorption toward chemical species, the enhanced light absorption and an efficient separation of photogenerated electron-hole pairs and transfer of charge carriers.  相似文献   

19.
水热沉淀法制备掺铁二氧化钛中空球及其光催化性能   总被引:1,自引:0,他引:1  
 以碳球为模板剂, 采用水热沉淀法制备了不同配比掺 Fe 的 TiO2 (Fe-TiO2) 中空球, 并运用 X 射线粉末衍射、扫描电子显微镜、元素分析能谱、红外光谱和热重等方法对其进行了表征. 结果表明, 中空球为锐钛矿相, 大小为 0.5~3.20 ?m, 壳层厚度为 30~60 nm, 比表面积为 150~300 m2/g. 随着 Fe 掺杂量的增加, 中空球在可见光区的吸收强度逐渐增加. 光催化降解实验表明, 掺 Fe 后, TiO2 中空球的可见光催化活性升高, 其中 0.5% Fe-TiO2 在 80 min 内降解亚甲基蓝超过 75%. 同时还讨论了光催化机制.  相似文献   

20.
TiO2–graphene oxide nanocomposites have been fabricated by the sol–gel technique for degradation of a typical cationic dye solution. The prepared photocatalysts were characterized by X‐ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric‐differential analyses, Brunauer–Emmett–Teller surface area measurement, and scanning and transmission electron microscopy. In addition, the photocatalytic activities of samples were evaluated by degradation of methylene blue aqueous solution under the sunlight irradiation. The change in color of solution was evaluated by the UV–vis spectroscopy, and the maximum photocatalytic decoloration (94%) was achieved within 60 min, which exceeded that of pure anatase under the same conditions. The results show that the nanocomposite containing 9.0 wt% of graphene oxide has the superior photocatalytic performance to either single‐phase anatase or other composites containing different amounts of graphene oxide. The experimental degradation data obtained from the batch tests were analyzed by a modified kinetic model, which predicted the performance with higher regression coefficients and lower relative errors. The distribution of TiO2 nanoparticles (<20 nm) on graphene oxide sheets is proposed to be the efficient factor in the homogeneous degradation of dye which can concomitantly improve the photocatalytic activity.  相似文献   

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