可见光响应型Fe掺杂SiO2/TiO2光催化材料的制备及降解水中腐殖酸的研究

采用溶胶凝胶法制备了可见光响应型Fe掺杂SiO2/TiO2光催化材料,并采用TG-DTA、XRD、UV-vis、TEM及XPS等手段对其进行了表征.以水中腐殖酸的降解为探针反应,考察了可见光照射下Fe-SiO2/TiO2的光催化活性.XRD结果表明,Fe离子掺杂可抑制催化剂晶粒尺寸,600℃焙烧后的Fe-SiO2/TiO2为锐钛矿相结构.Ur-vis吸收光谱分析可看出Fe离子掺杂提高了催化剂对可见光的吸收能力,并使催化剂的吸收带边产生了红移.XPS光谱表明,催化剂表面存在着Fe2+和Fe3+.实验结果表明,Fe-SiO2/TiO2在可见光下对腐殖酸的光催化降解率优于SiO2/TiO2和TiO2.Fe-SiO2/TiO2具有较高光催化活性的主要原因为:Fe离子掺杂不仅使SiO2/TiO2催化剂的粒径减小和对可见光的吸收增强,而且在催化剂表面产生了有利于光生e--h+对分离的Fe3+/Fe2+氧化还原循环电对.     

Bi2 S3/TiO2复合光催化剂的制备及光催化还原Cr(Ⅵ)性能研究

环境中污染物的低耗能绿色处理方法,特别是环境中重金属Cr(Ⅵ)的绿色处理方法,是近年来的热点研究领域.本文首先制备了TiO2单晶颗粒,之后与不同量的Bi2 S3进行复合,制备了Bi2 S3/TiO2复合光催化材料.研究了不同的Bi2 S3复合量对所制备样品的组成、形貌、结构和光催化还原Cr(Ⅵ)性能的影响.通过XRD、SEM、TEM、DRS、SPV等方法对样品进行了表征.研究结果表明,TiO2表面复合有棒状的Bi2 S3,复合样品对Cr(Ⅵ)的可见光光催化还原效率明显高于纯TiO2,其中0.02 mol/L的Bi(NO3)3反应液制备的复合样品具有最高光催化还原效率.对样品催化机理研究表明,Bi2 S3/TiO2复合材料的带隙随着Bi2 S3含量的增加而变窄,对可见光的吸收和利用效率明显提高;并且TiO2与Bi2 S3的复合,可以减弱光生电子和空穴的复合,从而有效地利用了光生电子,提高了样品对Cr(Ⅵ)的光催化还原效率.     

铋铁共掺纳米TiO2复合薄膜的制备及光催化性能

本文以钛酸丁酯、硝酸铋、硝酸铁为主要原料,采用溶胶-凝胶法制备了铋铁共掺的纳米TiO2复合薄膜.用XRD、UV-VIS、SEM及降解率等方法对样品进行了表征.以甲基橙为降解物,考察Bi3+和Fe3+掺杂对TiO2复合薄膜催化剂的光催化活性影响及其机理研究.结果表明Bia+和F3+掺杂后,纳米TiO2复合薄膜光催化活性有了明显的提高.     

α-Fe2O3/TiO2光催化剂的制备及可见光催化降解罗丹明B的研究

采用浸渍法制备不同掺杂量的负载型光催化剂 α-Fe2O3/TiO2,通过XRD、SEM-EDX、XPS和N2-sorption等手段对其进行表征,并研究其在可见光照射下对罗丹明B的降解性能.考察了不同掺杂量的复合纳米粒子、不同浓度的H2O2溶液、不同pH等条件对可见光降解罗丹明B的影响.结果表明,复合α-Fe2O3/TiO2催化剂的光催化活性均高于单一的α-Fe2O3或TiO2,其中α-Fe2O3掺杂量为6.0wt;的α-Fe2O3/TiO2的光催化活性和光降解稳定性最好.     

(1-x)Ba_(0.998)La_(0.002)TiO_3+xBi_4Ti_3O_(12)陶瓷电性能的研究

采用固相法制备了(1-x)Ba0.998La0.002TiO3+xBi4Ti3O12(0≤x≤0.03)陶瓷,研究了Bi4Ti3O12掺杂量以及烧结气氛对Ba0.998La0.002TiO3陶瓷显微结构、居里温度Tc及介电性能的影响。结果表明:Bi4Ti3O12在Ba0.998La0.002TiO3陶瓷中的掺杂抑制了陶瓷晶粒的生长,使居里温度提高到约150℃。在空气中烧结的陶瓷的介电常数随Bi4Ti3O12掺杂量的增加先减小后增大,当Bi4Ti3O12掺杂量为1.5 mol%时,陶瓷的介电常数最小(还原再氧化陶瓷的介电常数为6.0×103,空气中烧成的陶瓷的介电常数为9.0×102)。     

稀土离子Er3+掺杂Bi2WO6的第一性原理计算及可见光催化性能研究

采用溶剂热法合成了稀土离子Er3+掺杂Bi2WO6光催化剂.采用密度泛函理论(DFT)研究了Er3+掺杂Bi2WO6的晶体结构和电子结构.DFT计算结果表明,Er3+掺杂后在价带顶形成了Er杂质能级,Bi2WO6的带隙减小,有利于光生电子的生成和光生载流子的复合.实验结果表明,Er3+掺杂量对Bi2WO6的显微形貌影响不大.掺杂Er3+后,Bi2WO6的光催化性能得到显著提高,当掺杂4;摩尔比的Er3+时,产品的光催化性能最好,可见光照射150分钟后,可降解91.5;的罗丹明B,较未掺杂Bi2WO6的光催化性能提高了83;.     

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.     

V掺杂TiO2/粉煤灰漂珠光催化降解DMF的研究

以粉煤灰漂珠为载体、钛酸四丁酯为钛源、偏钒酸铵为钒源,采用溶胶凝胶法制备了V掺杂TiO2/粉煤灰漂珠光催化复合材料.采用XRD、UV-Vis/DRS、XPS、SEM、EDS等测试手段对其进行了表征分析,以二甲基甲酰胺(DMF)为有机污染物对其光催化活性进行了研究.结果表明:粉煤灰漂珠表面负载的TiO2为锐钛矿型;掺杂的V以V5、V4的形式存在于TiO2品格中,V的掺杂能够促使TiO2产生可见光响应(红移)而且能够提高催化剂的光催化活性,但是,掺杂过量的V会导致光催化活性降低;确定了当最佳V掺杂量为1;,加入量为0.5g时,暗反应30 min、光催化180 min后对浓度为50 mg/L、pH =3的DMF溶液的去除率达88.2;,循环使用4次后,对DMF溶液的去除率仍在65;以上,显示出较好的光催化性能和稳定性.     

Er掺杂钛酸锶的制备及可见光催化性能研究

通过水热法制备了Er3+掺杂的SrTiO3系列光催化剂,对样品进行了X射线衍射、扫描电镜、紫外可见吸收光谱和比表面积分析,并以染料降解考察了样品的光催化活性.研究表明,Er3+的适量掺杂抑制了SrTiO3粒径生长,增加了SrTiO3对太阳光的利用率.在紫外光和可见光辐照下,水热法制备Er3+-SrTiO3的光催化活性优于纯SrTiO3和高温固相反应制备的Er3+-SrTiO3.当掺杂量为1.5;时,SrTiO3的光催化活性达到最大,且在可见光辐照下的光催化活性优于TiO2(P25)光催化剂.     

Ag/Bi2S3/Bi2WO6复合催化剂合成及光催化性能研究

以硝酸铋、钨酸钠和硫脲为起始原料,采用一步水热法成功合成Bi2 S3/Bi2 WO6光催化剂,采用光还原法在Bi2S3/Bi2 WO6表面沉积贵金属Ag.采用XRD、XPS、FESEM、TEM和UV-Vis-DRS等手段对Bi2S3/Bi2WO6和Ag/Bi2S3/Bi2WO6进行表征,并以罗丹明B和苯酚作为模型污染物对其光催化性能进行研究.结果证明,耦合Bi2S3可以提高Bi2WO6催化剂的光催化活性,Ag沉积使得其光催化性能进一步提高,且Ag的沉积量与催化剂的活性关系密切,其中5; Ag/Bi2S3/Bi2WO6的光催化效果最好.此外,结合活性物种检测和能带结构分析,对Ag/Bi2S3/Bi2WO6的光催化活性增强机理进行了分析.     

Crystal and molecular structures oftrans-dichloro-(ethylene) (4-methylpyridine)platinum(II) andtrans-dichloro(ethylene) (2,4,6-trimethylpyridine)platinum(II)

The crystal and molecular structures oftrans-[PtCl₂(C₂H₄)(4-MeC₅H₄N)] (I) andtrans-[PtCl₂(C₂H₄)(2,4,6-Me₃C₅H₂N)] (II) have been determined by single-crystal x-ray methods.I crystallizes in space groupP2₁/c witha= 4.991(1), b=21.658(3), c=10.675(3) Å, =110.17(2) °,Z=4;II is orthorhombic (Pbca) witha=10.295(6),b=12.393(8),c=20.370(10) Å,Z=8.Full-matrix least-squares refinements have given finalR factors of 0.053 (1520 reflections) forI and 0.042. (1412 reflections) forII. The intensities were recorded by counter methods, and only those reflections havingI>3(I) were used in the analyses.In both complexes, platinum is four-coordinate with the two chlorine atoms, the double bond of the ethylene, and the nitrogen atom of the substituted pyridine. The two structures are discussed in terms of the arrangement of the pyridine ligand with respect to the PtCl₂(C₂H₄) moiety.     

Synthesis, spectroscopy, and X-ray structures of fac-(CO)3(dppe)MnSC(S)H, fac-(CO)3(dppe)ReSC(S)H, fac-(CO)3(dppp)ReSC(S)H, and fac-(CO)3(dppb)ReSC(S)H

The monodentate dithioformato complexes, fac-(CO)₃(dppe)MnSC(S)H (1), fac- (CO)₃(dppe)ReSC(S)H (2), fac-(CO)₃(dppp)ReSC(S)H (3), and fac-(CO)₃ (dppb)ReSC(S)H (4), where dppe is 1,2-bis(diphenylphosphino)ethane, dppp is 1,3-bis(diphenylphosphino)propane, and dppb is 1,4-bis(diphenylphosphino)butane, were synthesized from the treatment of the corresponding hydrides, fac-(CO)₃ (P-P)MSC(S)H with CS₂. Compounds 1–4 crystallize in the monoclinic crystal system: for 1, space group = P2₁/c, a = 15.3139(3) Å, b = 9.7297(4) Å, c = 19.0991(6) Å, = 105.928(1), V = 2736.5 ų, Z = 4; for 2, space group = P2₁/c, a = 15.6395(8) Å, b = 9.8182(5) Å, c = 19.4153(11) Å, = 106.741(1), V = 2854.9(3) ų, Z = 4; for 3, space group = P2₁/n, a = 11.3570(10) Å, b = 19.465(2) Å, c = 15.5702(14) Å, = 104.776(2), V = 3328.3(5) ų, Z = 4; and for 4, space group = C2/c, a = 32.078(2) Å, b = 10.4741(6) Å, c = 19.0608(9) Å, = 94.315(2), V = 6386.1(6) ų, Z = 8.     

Structure of (chloranilato)bis(tri-n-butylphosphine)palladium(II)

(Chloranilato)bis(tri-n-butylphosphine)palladium(II), [Pd(C₆Cl₂O₄){P(C₄H₉)₃}₂] (chloranilic acid=2,5-dichloro-3,6-dihydroxy-p-benzoquinone): FW=718.02,P2₁/c,a=21.729(6),b=17.293(5),c=21.010(9) Å,=112.62(3)°,V=7287.42 ų,Z=8,D _c=1.309mg m^–3, Mo, =0.710730 Å,=0.76 mm^–1,F(000)=3008, finalR=0.087, 2594 observed reflections. Palladium is ligated by a distorted square planar P₂O₂ coordination sphere in the title compound. The two molecules per asymmetric unit differ in the arrangement of phosphine n-butyl chains, yielding two unique metal centers.     

Crystal structure of triphenylphosphine-(1-(di(trifluoromethyl)-hydroxymethyl)-cyclopentadienyl)-(1,2-di(carboxymethyl) ethylene-1-yl) ruthenium (0)

The structure of triphenylphosphine — (1 — (di(trifluoromethyl) — hydroxymethyl) — cyclopentadienyl) — (1,2 — di(carboxymethyl)ethylene — 1 — yl) — ruthenium (0) has been studied by single-crystal X-ray diffraction techniques. This compound, [C₅ H₄(CF₃)2 COH] Ru(PPh₃)C2(CO₂Me)₂H, crystallizes in the triclinic space groupP¯1 witha =10.131,b= 15.107,c= 10.798 Å, = 102.14, = 107.04, = 89.64° andZ = 2. The structure was refined by block-diagonal least-squares methods to a finalR value of 0.042, including hydrogen atoms. The compound contains a dicarboxymethylethylene ligand coordinated to ruthenium both through a ketonic oxygen and through a metal--carbon -bond. An intramolecular hydrogen bond is observed. Details of the structure are reported, and the structures of several Ru(0) complexes are compared.     

X-ray crystal structures ofcis-bis(diphenylphosphinamide)tetracarbonylmolybdenum(0) andtrans-bis(N-methyl diphenylphosphinamide)tetracarbonylmolybdenum(0)

The X-ray crystal structures ofcis-Mo(CO)₄(Ph₂PNH₂)₂,I, andtrans-Mo(CO)₄(Ph₂PNHMe)₂,II, are presented. ComplexI crystallizes in the monoclinic space groupP2₁/c(a=13.433(1),b=12.2719(8),c=17.318(2)Å;=109.79(1)°;V=2686.1(8)ų;Z=4). ComplexII crystallizes in the triclinic space groupP¯1 (a=6.9986(8),b=10.328(1),c=11.241(2)Å,=107.58(1)°,=91.76(1)°, =101.28(1)°,V=756.1(4)ų,Z=1). The molybdenum coordination geometry in each complex is a slightly distorted octahedron. The molybdenum-carbon bond lengths for the carbonyls trans to phosphorus in complexI are shorter than those the carbonyls trans to other carbonyls. The average molybdenum-phosphorus distance inI (2.525(5)Å) is similar to those in other diphenylphosphinamide complexes and longer than the molybdenum-phosphorus distance inII in 2.4585(7)Å). The distance between two nitrogen atoms incis Mo(CO)₄(Ph₂PNH₂)₂ (3.74(3)Å) is significantly larger than the sum of their van der Waals radii (3.10 Å) indicating that the two nitrogens are not hydrogen bonded.     

Structure of (N-(2-hydroxyphenyl)-salicylaldiminopiperidino) Ni(II) complex

The crystal and molecular structure of the title complex, C₁₈H₁₉N₂O₂Ni, has been determined by direct methods. The compound crystallizes in the monoclinic crystal system witha=22.973(1),b=5.212(1),c=27.076(1)Å, β=106.46(1)°, space groupC2/c,V=3109.1(6)ų, Z=8, andD _x=1.51g cm^?3. The nickel atom is in a slightly distorted square-planar environment of two oxygens [Ni(1)?O(1) 1.824(3) and Ni(1)?O(2) 1.856(3)Å] and two nitrogens [Ni(1)?N(1) 1.849(3) and Ni(1)?N(2) 1.932(3)Å] with O?Ni?N angles between 85.7(1) and 97.1(1)°. The nickel atom is 0.006 Å out of the plane of its ligands.     

Crystal and molecular structures of trans-bis(acetonitrile)bis(bipyridine)ruthenium(II) perchlorate and trans-diamminebis(bipyridine)ruthenium(II) perchlorate

The structures of trans-[(MeCN)₂(bpy)₂Ru](ClO₄)₂(I) andtrans-[(NH₃)₂(bpy)₂Ru](ClO₄)₂(II) have been determined by single crystal X-ray diffraction methods. (I) forms monoclinic crystals in the space groupP2₁/c witha=8.399(2),b=10.406(2),c=15.590(3) Å,=93.78(2)° andZ=2 atT=293 K. The final refinement gaveR=0.040 for 2448 reflections withF _o ² >3(F _o ² ). (II) crystallizes in the triclinic space groupP¯1 witha=1.702(1),b=8.439(2),c=10.525(2) Å,=107.56(2),=104.63(1), =100.89(2)° andZ=1 atT=293 K. Refinement using 1878 reflections withF _o ² >3(F _o ² ) produced a finalR value of 0.036. Both of these structures have the ruthenium atom located on a crystallographic inversion center. The bipyridine ligands in both structures are in the bowed conformation as a means of circumventing the steric problems associated with the trans arrangement of the bipyridine ligands. The Ru-N(monodentate) distance is longer for the ammonia complex (2.106(3) Å) than for the acetonitrile complex (2.008(4) Å); there are no significant differences in the distances and angles of the two Ru(bpy)₂ frameworks.     

X-ray crystal structure of trans-bis(monoethanolamine) bis(saccharinato)nickel(II)

The crystal structure of trans-bis(monoethanolamine)bis(saccharinato)nickel(II), [Ni(C₇H₄NO₃S)₂(C₂H₇NO)₂], has been determined from X-ray diffraction data. The metal complex is monoclinic, with a = 11.0555(5), b = 8.9103(4), c = 11.3890(5) Å, = 105.0230(10)°, Z = 2, and space group P2_1/c . The structure consists of individual molecules. Two monoethanolamine molecules and two saccharinate anions coordinate the nickel atom forming a distorted octahedron. The monoethanolamine molecules act as a bidentate ligand and form five-membered trans chelate rings, which constitute the plane of the coordination octahedron, while two saccharinate ions behave as a monodentate ligand occupying the axial positions. Intermolecular hydrogen bonds link the molecules to form a three-dimensional infinite structure.     

X-ray structures of tris(0-cyclohexyl-dithiocarbonato)bismuth(III) and tris(0-benzyl-dithiocarbonato)bismuth(III)

The crystal structures of two Bi tris xanthates are reported, namely [Bi(S₂CO-c-C₆H₁₁)₃ J and [Bi(S₂COCH₂C₆H₅)₃]. They exist as centrosymmetric dimers, owing to the presence of bridging xanthate ligands, with seven-coordinate Bi atoms. The presence of a stereochemically active lonepair of electrons in each structure distorts the coordination geometry defined by seven S atoms and causes the elongation of some of the Bi-S bond distances. Crystals of both compounds are triclinic, space groupP¯1 with unit cell dimensions for [Bi(S₂CO-c-C₆H₁₁)₃]:a=12.417(3),b=13.571(3),c=9.681(4) Å;=102.30(2),=109.21(2), =66.23(2)° andZ=2; and for [Bi(S₂COCH₂C₆H₅)₃]:a=14.747(2),b=15.966(2),c=5.991(1) Å;=95.08(1),=98.51(1), =104.92(1)° andZ=2. The structures were refined by a full-matrix least-squares procedure to finalR=0.045 using 4274 reflections for [Bi(S₂CO-c-C₆H₁₁)₃] and toR=0.027 using 3993 reflections for [Bi(S₂COCH₂C₆H₅)₃].