Ag3PO4/ATP纳米复合材料的制备及可见光催化性能研究

以天然矿物凹凸棒石(简称ATP)为载体,在其表面原位生成纳米Ag3PO4,制备Ag3POJATP复合光催化剂.利用X射线衍射(XRD)、透射电子显微镜(TEM)、紫外-可见漫反射光谱(Uv-vis DRS)等测试方法对复合材料的表面结构、形貌、光响应性能进行了研究.结果表明:Ag3PO4/ATP复合光催化剂中Ag3PO4-以纳米微球均匀分布在ATP表面,平均直径12.5 nm.进一步通过150 W碘钨灯下降解甲基橙(MO)的实验,研究了光催化材料的可见光催化性能.实验结果表明,Ag3PO4、Ag3PO4/ATP在可见光下具有光催化活性,Ag3PO4/ATP的光催化性能优于Ag3PO4,2.5h对甲基橙的降解率达到93.4;.     

Ag3PO4/ZnO复合粉体制备及其可见光催化性能

室温下,以ZnO粉体、Na2HPO4、AgNO3和聚乙烯吡咯烷酮为原料,成功制备出了系列Ag3PO4/ZnO复合粉体.采用X射线衍射仪、扫描电子显微镜和紫外-可见光谱仪分别对复合粉体的物相、形貌和可见光吸收性能进行了表征.研究了不同摩尔比的Ag3PO4/ZnO复合粉体的光催化性能.结果表明:当ZnO和Ag3PO4摩尔比约为1:1时,所得的Ag3PO4/ZnO复合粉体对罗丹明B染料的可见光催化效果最好,降解率达到99;.     

三维In2S3/Ag/TiO2纳米网对9-蒽羧酸的光催化性能研究

采用光催化还原法以及连续离子层吸附法(SILAR)分别将Ag和In2S3纳米粒子修饰在TiO2纳米网上,成功制备了In2 S3/Ag/TiO2复合纳米材料.通过光催化降解9-蒽羧酸(9-ACA)来评价催化剂的光催化性能以及优化In2S3的沉积圈数.实验发现,In2S3/Ag/TiO2复合纳米材料的光吸收范围从紫外光区扩展至可见光区,并表现出增强的光催化降解9-ACA的效率.其中,沉积了7圈In2S3的In2S3/Ag/TiO2纳米网表现出最高的光催化降解效率,在60 min内,对9-ACA的降解效率达到了98.66;.此外,本文还对In2S3/Ag/TiO2复合纳米材料光催化降解9-ACA的机理进行了讨论.     

Ag/g-C3N4纳米片的制备及可见光催化抗菌性能研究

在液相超声剥离制备g-C3 N4纳米片的基础上,通过光照还原法负载Ag纳米颗粒,成功构筑Ag/g-C3 N4纳米片,通过透射电子显微镜(TEM)、红外光谱仪(FT-IR)、X-射线衍射仪(XRD)、比表面积和孔分析仪(BET)和瞬态光电流等方法对制备的样品进行表征,考察可见光下杀灭E.coli能力以表征其光催化活性,并通过改进的Hom模型对样品的光催化抗菌动力学进行研究.研究结果表明,3;Ag/g-C3 N4纳米片具有最优的光催化抗菌活性,光催化抗菌曲线拟合的k2值是体相g-C3 N4的2.99倍,是3;Ag/体相g-C3 N4的1.45倍.大的比表面积和良好的光生载流子分离效率是3;Ag/g-C3 N4纳米片具有优异光催化抗菌活性的主要原因.     

Ag3PO4/TiO2复合催化剂的制备及光催化性能研究

为提高纳米TiO2的光催化降解性能和稳定性,采用两步水热法制备具有高催化性能的Ag3PO4/TiO2复合催化剂,采用XRD、SEM、EDS、XPS、TEM等仪器对其表面微观形貌和形态大小、表面元素组成、物相结构等进行表征,并研究了TiO2的比表面积和Ag3PO4颗粒尺寸大小对Ag3PO4/TiO2光催化性能的影响.以亚甲基蓝(MB)和苯酚为目标降解物来考察复合光催化剂的光催化性能.结果表明:1h后Ag3PO4、TiO2、Ag3PO4/TiO2对亚甲基蓝的降解率为25;、42;、92;;复合光催化剂Ag3PO4/TiO2经过5次光催化降解实验后,对亚甲基蓝的降解率仍可达78;.     

可磁分离TiO2/BiOI复合纤维的制备及光催化性能

本工作合成了一种可磁分离TiO2/BiOI复合纳米纤维(TiO2/Fe3O4/BiOI),并研究了其可见光催化性能.通过静电纺丝技术获得TiO2纳米纤维,采用溶剂热法在TiO2纳米纤维表面生长Fe3 O4纳米颗粒,最后,在磁场辅助下,通过连续离子吸附反应(SILAR)法在TiO2/Fe3O4表面生长了BiOI纳米片.结果表明,Fe3O4纳米颗粒直径均一,均匀分布在TiO2纳米纤维表面.BiOI纳米片呈交错状垂直沉积在TiO2纳米纤维表面,BiOI纳米片的负载量可以通过SILAR的循环次数控制.光催化测试表明,由于BiOI对可见光吸收的增加,以及与TiO2间形成的半导体异质结,TiO2/Fe3 O4/BiOI复合纳米纤维的光催化效率均高于TiO2/Fe3 O4纳米纤维.此外,TiO2/Fe3 O4/BiOI对外磁场有强的响应,易于进行磁分离回收.     

Ag3PO4/GO复合材料制备及其光催化性能研究

采用原位沉淀法以GO为基体负载Ag3PO4纳米颗粒制备Ag3PO4/GO复合材料,利用扫描电镜(SEM)、X射线衍射(XRD)等方法对其进行表征,结果显示,Ag3PO4纳米颗粒呈现近似球状,巨在GO薄膜表面均匀分布.光催化降解RhB结果表明,Ag3PO4/GO复合材料在可见光下具有很好的光催化性能,光照60 min后,RhB降解率可达95.7;,较之纯Ag3PO4有着显著增加.催化剂重复使用4次,降解率仍然达到80.7;,表现出较好的稳定性.降解机理研究表明,h+是降解RhB的主要活性物质.     

Ag/TiO2的制备及光催化性能研究

以钛酸丁酯为钛源,采用溶胶-凝胶法制备了Ag掺杂纳米TiO2,结合XRD、TEM、Uv-vis等测试手段,对样品的结构和性能进行了表征.以甲基橙溶液为目标降解物,探讨了Ag掺杂纳米TiO2的光催化活性,分析了Ag掺杂纳米TiO2提高光催化性能的机理.结果表明,Ag掺杂使TiO2晶粒减小,拓展了TiO2的光谱响应范围,降低了光生电子和空穴的复合几率;Ag掺杂后,TiO2光催化剂的吸收光谱向可见光区发生红移.Ag掺杂量为n(Ag)∶n(TiO2)=0.08;,紫外光下240 min,Ag掺杂纳米TiO2前后材料对甲基橙溶液去除率由60.3;提高到83.1;.     

三维Ag2O/WO3复合催化剂的制备及光催化性能研究

WO3是一种带隙约为2.7 eV的过渡金属半导体,可见光就能激发其光催化活性,这极大地提高了太阳光的利用率,但纯WO3纳米材料催化活性偏低,针对这一难题,本文选取了三维网格结构的WO3纳米材料为载体,利用化学搅拌法制备了不同摩尔比的Ag2O/WO3复合光催化剂.选择亚甲基蓝为研究对象,测定了不同摩尔比的Ag2O/WO3复合催化剂的光催化性能.实验表明,当Ag2O和WO3的摩尔配比为1∶2时,该复合催化剂的光催性能最好.过量的Ag2O纳米颗粒会增加Ag2O/WO3内部电子空穴的复合几率,反而导致光催化剂反应活性的降低.     

可磁分离的"核-壳"结构Fe3O4@SiO2/Bi2WO6/Ag2O催化材料的制备及光催化性能研究

采用沉淀-沉积法制备了磁性Fe3O4@SiO2/Bi2 WO6/Ag2O催化材料,利用XRD、SEM和UV-Vis-DRS光谱对其组成、形貌和光吸收特性进行表征.以氙灯模拟可见光,以罗丹明B为模拟污染物对所得催化剂进行性能评价,考察了不同Ag2O复合量对Bi2WO6光催化剂反应活性的影响.结果表明,Fe3O4@SiO2/Bi2WO6/Ag2O的光催化活性明显优于纯Bi2 WO6,当Ag2 O的复合量为0.6;时,催化剂的活性最好.催化剂的活性增强增强机理分析表明,Ag2O的复合有效地降低了Bi2WO6的光生电子-空穴复合率,增加了Bi2WO6的可见光吸收范围.此外,该催化材料可进行磁分离,易于回收重复利用.     

Calculation of phase diagrams in AlxIn1−xAs/InP,AsxSb1−xAl/InP and AlxIn1−xSb/InSb nano-film systems

The models for calculation of phase diagrams of semiconductor thin films with different substrates were proposed by considering the contributions of strain energy, the self-energy of misfit dislocations and surface energy to Gibbs free energy. The phase diagrams of the Al_xIn_1−xAs and As_xSb_1−xAl thin films grown on the InP (1 0 0) substrate, and the Al_xIn_1−xSb thin films grown on the InSb (1 0 0) substrate at various thicknesses were calculated. The calculated results indicate that when the thickness of film is less than 1 μm, the strain-induced zinc-blende phase appears, the region of this phase extends with decreasing of the layer thickness, and there is small effect of surface energies of liquid and solid phases on the phase diagrams.     

Elastic properties of GexAsySe100−x−y glasses

The elastic properties of Ge_xAs_ySe_100−x−y (0x30; 10y40) glasses have been studied. The results were analyzed in terms of the dependence on the theoretical mean coordination number (mean number of covalent bonds per atom) m (m=2+(2x+y)×0.01). Three ranges of m (2.1m2.51, 2.51<m2.78, 2.78<m3) were revealed, where different dependencies of elastic moduli (Young’s modulus, shear modulus) and Poisson’s ratio of glasses on m were observed.     

Crystal growth of NdAl3(BO3)4 from K2O/MoO3/Nd2O3/B2O3/KF flux

NdAl₃(BO₃)₄ single crystals were grown by the flux method and the TSSG technique using a K₂O/3MoO₃/B₂O₃/0.5Nd₂O₃/KF flux system. Light-violet clear crystals could be obtained. The effects of fluoride on the growth of NAB crystals were investigated. As the content of KF was gradually increased, the growth form of NAB was changed from the equant to the columnar and the primary crystalline region of NAB was shrinked. At the ratio of KF/K₂O = 0.75, NAB crystals could not be grown.     

Synthesis and structure of new phases of the Am?1Bi2BmO3m+3 (m = 2) type

Three polycrystalline bismuth-containing layered perovskite-like oxides are synthesized by high-temperature solid-state reactions. One of these compounds was described previously, namely, Bi₃Ti_1.5W_0.5O₉, for which the unit cell parameters a = 5.372(5) Å, b = 5.404(4) Å, and c = 24.95(2) Å are determined in this study. The other two compounds, namely, Na_0.75Bi_2.25Nb_1.5W_0.5O₉ with the unit cell parameters a = 5.463(1) Å, b = 5.490(7) Å, and c = 24.78(0) Å and Ca_0.5Bi_2.5Ti_0.5Nb_1.5O₉ with the unit cell parameters a = b = 3.843(2) Å and c = 24.97(6) Å, are synthesized for the first time. The compositions of these compounds are based on the composition of the well-known compound Bi₃TiNbO₉ with a high Curie temperature (T _C = 1223 K), in which bismuth, niobium, and titanium atoms are partially or completely replaced by other atoms. The experimental and calculated interplanar distances determined from the X-ray diffraction patterns of the studied compounds are presented. __________ Translated from Kristallografiya, Vol. 50, No. 1, 2005, pp. 59–64. Original Russian Text Copyright ? 2005 by Geguzina, Shuvaev, Shuvaeva, Shilkina, Vlasenko.     

Vapour epitaxial growth and characterization of InAs1-xPx

The vapour growth of InAs_1-xP_x layers has been carried out by the hydride process. The phosphorus rich part of the system (0.7 ? x ? 1) was especially investigated. Heteroepitaxial deposits of InAs_1-xP_x and InP have been performed on substrates such as InAs, GaAs and GaP. A systematic study of the influence of the substrate orientation on the quality of the layer has been carried out by growth on hemispherical substrates. Preferential planes have been pointed out: (100) and (111) A for InAs, (111) for GaAs and GaP. The band gap variation as a function of the composition has been determined by photoluminescence at 4.2 °K and X-ray diffraction measurements. It fits the equation: E_G(x) eV = 0.425 + 0.722 x + 0.273 x² at 4.2 °K.     

Digitally alloyed modulated precursor flow epitaxial growth of AlxGa1−xN layers with AlN and AlyGa1−yN monolayers

We propose a new growth scheme of digitally alloyed modulated precursor flow epitaxial growth (DA-MPEG) using metalorganic and hydride precursors for the growth of Al_xGa_1−xN layers with high-Al content at relatively low temperatures. The growth of high-quality, high-Al content Al_xGa_1−xN layers (x_Al>50%) that are composed of AlN and Al_yGa_1−yN monolayers on AlN/sapphire template/substrates by DA-MPEG was demonstrated. The overall composition of the ternary Al_xGa_1−xN material by DA-MPEG can be controlled continuously by adjusting the Column III mole fraction of the atomic Al_yGa_1−yN sub-layer. X-ray diffraction and optical transmittance results show that the AlGaN materials have good crystalline quality. The surface morphology of DA-MPEG AlGaN samples measured by atomic force microscopy are comparable to high-temperature-grown AlGaN and are free from surface features such as nano-pits.     

Crystallization behaviours ofCo100−1(x+y)NbxBy amorphous alloys

The crystallization behaviours of Co_100?1(x+y)Nb_xB_y amorphous alloys were investigated by means of differential thermal analysis and a conventional X-ray diffractometer. The crystallization sequences are discussed in terms of the equilibrium phase diagram of the ternary alloy system.Assuming crystallization occurs as a result of nucleation and growth, the stabilizing effect of eutectic phase separation on the crystallization is shown by introducing the effective free energy of the critical nucleus.