掺氮TiO_2的制备与光谱分析

用硫酸钛与氨水反应得到TiO2前体,煅烧后制得掺氮TiO2粉体,研究了不同温度和加热时间下掺氮TiO2的XPS、FTIR和紫外可见光谱,结果表明,掺氮TiO2在400℃下加热1 h,所得粉体是锐钛矿相结构,与未掺杂TiO2相比,吸收边红移22 nm,对400~510 nm的可见光有一定的吸收率。氮的掺杂不仅使TiO2带隙变小,而且有助于氧空位的形成。     

Reduced charge recombination in a co-sensitized quantum dot solar cell with two different sizes of CdSe quantum dot

An efficient photoelectrode is fabricated by sequentially assembling 2.5 nm and 3.5 nm CdSe quantum dots (QDs) onto a TiO2 film. As revealed by UV-vis absorption spectroscopy, two sizes of CdSe QD can be effectively adsorbed on the TiO2 film. With a broader light absorption range and better coverage of CdSe QDs on the TiO2 film, a power conversion efficiency of 1.26% has been achieved for the TiO2/CdSe QD (2.5 nm)/CdSe QD (3.5 nm) cell under the illumination of one Sun (AM 1.5G, 100 mW cm(-2)). Electrochemical impedance spectroscopy shows that the electron lifetime for the device based on TiO2/CdSe QD (2.5 nm)/CdSe QD (3.5 nm) is longer than that for devices based on TiO2/CdSe QD (2.5 nm) and TiO2/CdSe QD (3.5 nm), indicating that the charge recombination at the interface is reduced by sensitizing with two kinds of CdSe QDs.     

Novel hollow mesoporous 1D TiO2 nanofibers as photovoltaic and photocatalytic materials

Hollow mesoporous one dimensional (1D) TiO(2) nanofibers are successfully prepared by co-axial electrospinning of a titanium tetraisopropoxide (TTIP) solution with two immiscible polymers; polyethylene oxide (PEO) and polyvinylpyrrolidone (PVP) using a core-shell spinneret, followed by annealing at 450 °C. The annealed mesoporous TiO(2) nanofibers are found to having a hollow structure with an average diameter of 130 nm. Measurements using the Brunauer-Emmett-Teller (BET) method reveal that hollow mesoporous TiO(2) nanofibers possess a high surface area of 118 m(2) g(-1) with two types of mesopores; 3.2 nm and 5.4 nm that resulted from gaseous removal of PEO and PVP respectively during annealing. With hollow mesoporous TiO(2) nanofibers as the photoelectrode in dye sensitized solar cells (DSSC), the solar-to-current conversion efficiency (η) and short circuit current (J(sc)) are measured as 5.6% and 10.38 mA cm(-2) respectively, which are higher than those of DSSC made using regular TiO(2) nanofibers under identical conditions (η = 4.2%, J(sc) = 8.99 mA cm(-2)). The improvement in the conversion efficiency is mainly attributed to the higher surface area and mesoporous TiO(2) nanostructure. It facilitates the adsorption of more dye molecules and also promotes the incident photon to electron conversion. Hollow mesoporous TiO(2) nanofibers with close packing of grains and crystals intergrown with each other demonstrate faster electron diffusion, and longer electron recombination time than regular TiO(2) nanofibers as well as P25 nanoparticles. The surface effect of hollow mesoporous TiO(2) nanofibers as a photocatalyst for the degradation of rhodamine dye was also investigated. The kinetic study shows that the hollow mesoporous surface of the TiO(2) nanofibers influenced its interactions with the dye, and resulted in an increased catalytic activity over P25 TiO(2) nanocatalysts.     

N-Ion-implanted TiO2 photoanodes in quantum dot-sensitized solar cells

Hierarchical nanostructured titanium dioxide (TiO(2)) clumps were fabricated using electrostatic spray with subsequent nitrogen-ion doping by an ion-implantation technique for improvement of energy conversion efficiency for quantum dot-sensitized solar cells (QDSCs). CdSe quantum dots were directly assembled on the produced N-ion-implanted TiO(2) photoanodes by chemical bath deposition, and their photovoltaic performance was evaluated in a polysulfide electrolyte with a Pt counter electrode. We found that the photovoltaic performance of TiO(2) electrodes was improved by nearly 145% upon N-ion implantation. The efficiency improvement seems to be due to (1) the enhancement of electron transport through the TiO(2) layer by inter-particle necking of primary TiO(2) particles and (2) an increase in the recombination resistance at TiO(2)/QD/electrolyte interfaces by healing the surface states or managing the oxygen vacancies upon N-ion doping. Therefore, N-ion-doped photoanodes offer a viable pathway to develop more efficient QD or dye-sensitized solar cells.     

Growth behaviour and plasmon resonance properties of photocatalytically deposited Cu nanoparticles

Cu nanoparticles (NPs) were deposited on UV-irradiated TiO(2) in an aqueous solution containing Cu(CH(3)COO)(2) and ethanol by a photocatalytic reaction. Cu NPs on TiO(2) exhibit an extinction (= absorption + scattering + reflection) peak due to localized surface plasmon resonance at around 600 nm initially. The density and size as well as the extinction of Cu NPs increase during the deposition, accompanied by a slight redshift of the peak. Eventually, TiO(2) is mostly covered with coalesced Cu NPs that exhibit a spectrum less characteristic of Cu NPs, but more characteristic of a Cu layer.     

TiO_2/SiO_2复合纳米纤维的GQDs改性及其对甲醛的可见光催化降解性能

采用静电纺丝法合成了TiO_2/SiO_2柔性复合纳米纤维膜,而后对其进行石墨烯量子点(GQDs)改性,制备了GQDs/TiO_2-SiO_2复合纳米纤维,其中GQDs用水热法合成。用X射线衍射仪(XRD)、电子万能材料试验机、扫描电子显微镜(SEM)、紫外-可见分光光度计(UV-Vis)对其物相组成、力学性能、微观形貌以及光催化性能进行了表征。结果表明:尺寸在7 nm~15 nm之间的GQDs松散沉积在直径为200 nm~400 nm的TiO_2/SiO_2纳米纤维上,纤维连续性好,复合薄膜有较好的力学性能;TiO_2的结晶较好,为锐钛矿相;GQDs复合后将TiO_2的本征吸收从390 nm左右延伸到了420 nm左右,拓宽了TiO_2的吸收范围。在可见光催化降解中,初始浓度为0.32 mg/m~3的甲醛气体110 min后的降解效率达到70%。     

N、F掺杂的TiO2膜电极在可见光条件下光电催化氧化诱惑红脱色效果的研究

纯TiO2光催化剂只能利用紫外光进行光催化反应,而通过金属／非金属掺杂可以扩大其波长吸收范围,实现在可见光条件下的光催化反应。该实验以NH4F作为添加剂,用溶胶一凝胶法制备N、F掺杂的TiO2粉末,并尝试用涂渍附着法制备了N、F掺杂的TiO2膜电极。选取诱惑红作为目标污染物,应用自制的斜板式液膜光电反应器,在≥400nm可见光照射下进行光电催化氧化性能的研究。考察了其可见光光电催化氧化的影响因素和光电催化的效率,确定最佳的优化条件为：偏压=1．0V,pH=1．5～2．0,Na2SO4=1000mg／L。可实现可见光条件下对30mg／L诱惑红染料溶液的脱色,其脱色率可达到40％。     

静电纺丝制备TiO2纳米纤维的光催化性能

纳米TiO2材料在光催化、抗菌等方面有着广泛应用。采用尺寸为20～30nm的TiO2颗粒与聚乙烯吡咯烷酮（PVP）的醇溶液混合制得纺丝液,通过静电纺丝技术与烧结工艺,制得TiO2纳米纤维。采用能谱仪、X射线衍射、扫描电子显微镜和投射电子显微镜等分析手段对样品进行了表征,与采用溶胶–凝胶结合静电纺丝技术得到的TiO2纳米纤维进行了形貌对比,并通过亚甲基蓝降解实验研究其光催化性能。结果表明：以TiO2纳米颗粒为原料通过静电纺丝技术制备的TiO2纳米纤维,主要为多晶相的锐钛矿结构,直径为150～250 nm,长度大于20μm,与溶胶–凝胶结合静电纺丝技术制得的TiO2纳米纤维相比,直径分布更为均匀。在紫外光照射90min时,对浓度为4mg/L的亚甲基蓝溶液的分解率为72%,具有较好的光催化效率。     

Microwave assisted CdSe quantum dot deposition on TiO2 films for dye-sensitized solar cells

CdSe quantum dot (QD ) sensitized TiO(2) films have been fabricated using a one-step microwave assisted chemical bath deposition (MACBD) technique and used as photoanodes for quantum dot sensitized solar cells. This technique allows direct and rapid deposition and a good contact between the CdSe and TiO(2) films. The photovoltaic performances of the cells with CdSe deposited at different times are investigated. The results show that cells based on MACBD deposited TiO(2)/CdSe electrodes achieve a maximum short circuit current density of 12.1 mA cm(-2) and a power conversion efficiency of 1.75% at one Sun (AM 1.5 G, 100 mW cm(-2)), which is comparable with those fabricated using conventional techniques.     

Pyrazolyl-diamine ligands that bear anthracenyl moieties and their rhenium(I) tricarbonyl complexes: synthesis, characterisation and DNA-binding properties

Two novel families of pyrazolyl-diamine ligands that bear an anthracen-9-yl group as a DNA-binding fragment, pz*(CH2)2NH(CH2)2NHCH2-9-anthryl (pz*=pz (L(1)), 3,5-Me2pz (L2)) and pz*(CH2)2NH(CH2)2NH(2 (pz*=4-(9-anthrylmethyl)pz (L3), 3,5-Me2-4-(9-anthrylmethyl)pz (L4)), have been prepared and fully characterised. In the case of L2-L4, the evaluation of their coordination capability towards the fac-[Re(CO)3]+ core led to the synthesis of the organometallic complexes fac-[Re(CO)(3){3,5-Me(2)pz(CH2)2NH(CH2)2NHCH2-9-anthryl}]Br (7) and fac-[Re(CO)3{4-(9-anthrylmethyl)pz*(CH2)2NH(CH2)2NH2}]Br (pz*=pz (8), 3,5-Me2pz 9). The interaction of the novel pyrazole-diamine ligands and the rhenium(I) complexes with calf thymus (CT) DNA has been investigated with a variety of spectroscopic techniques (UV-visible, fluorescence, circular dichroism (CD) and linear dichroism (LD)). All of the evaluated compounds have a moderate affinity to CT DNA (3.46x10(3)相似文献   

均匀沉淀法制备纳米二氧化工艺条件研究

以硫酸法钛白生产的中间产品硫酸氧钛（TiOSO4）为原料,以尿素为沉淀剂缩主,采用均匀沉淀法制备纳米TiO2 ,寻找出最佳的工艺条件：反应温度为120℃,反应时间为2h,反应物摩尔配比为TiOSO4:CO(NH2)2=1:2,反应物浓度为[TiO^2 ]=1.8mol/L。得到的纳米TiO2粒径为30-80nm,收率达到90%。     

城市生活污水回用于电厂的组合高级氧化技术

通过实验研究比较了UV／O3、UV／TiO2以及UV／O3／TiO2等三种高级氧化技术对城市生活污水中COD和NH3-N的去除效率，重点确定了UV／O3/TiO2法的主要工艺参数。研究结果表明，对于COD、NH3-N质量浓度分别为80～200mg／L和15—25mg／L的城市污水处理厂初沉池出水，用UV／O3／TiO2法处理2h后，COD去除率达到90％，NH3-N去除率达到70％，基本达到了回用于电厂的要求。     

Apoptosis induction and DNA interstrand cross-link formation by cytotoxic trans-[PtCl2(NH(CH3)2)(NHCH(CH3)2) : cross-linking between d(G) and complementary d(C) within oligonucleotide duplexes

We have investigated the cytotoxic activity, the induction of apoptosis, and the interstrand cross-linking efficiency in the A2780cisR ovarian tumor cell line, after replacement of the two NH3 nonleaving groups in trans-[PtCl2(NH3)2] (trans-DDP) by dimethylamine and isopropylamine. The data show that trans-[PtCl2(NH(CH)2)(NHCH(CH3)2)] is able to circumvent resistance to cis-[PtCl2(NH3)2] (cis-DDP, cisplatin) in A2780cisR cells. In fact, trans-[PtCl2(NH(CH3)2)(NHCH(CH3)2)] shows a cytotoxic potency higher than that of cis-DDP and trans-DDP, with the mean IC50 values being 11, 58, and 300 microM, respectively. In addition, at equitoxic doses (concentrations of the platinum drugs equal to their IC50 values) and after 24 hours of drug treatment, the level of induction of apoptosis by trans-[PtCl2(NH(CH3)2)(NHCH(CH3)2)] is twice that produced by cis-DDP. Under the same experimental conditions, trans-DDP does not induce significant levels of apoptosis in A2780cisR cells. After 24 hours of incubation of A2780cisR cells at concentrations equal to the IC0o value of the platinum drugs, the level of DNA interstrand cross-links (ICLs) induced by trans-[PtCI2(NH(CH)2)(NHCH(CH3)] is two and three times higher, respectively, than those induced by cis-DDP and trans-DDP. We also found that trans-[PtCl2(NH(CH3)2)(NHCH(CH3)2)] formed DNA ICLs between guanine and complementary cytosine. We propose that, in A2780cisR cells, the induction of apoptosis by trans-[PtCl2(NH(CH3)2)(NHCH(CH3)2)] is related to its greater ability (relative to cis-DDP and trans-DDP) to form DNA ICLs.     

UV/TiO2法对炼油含碱废水预处理的实验

用UV／TiO2法对炼油含碱废水进行预处理实验，TiO2以悬浮态存在于废水中，对油类有较高的去除率，且随着TiO2投加量的增加而升高。在本实验的条件下，在TiO2加入量为20g时，COD、酚类、NH3-N的平均去除率达到最高，分别为61％，58％，50％，此时，油的平均去除率为68％，但S2-的降解几乎不受TiO2影响，平均去除率在94％以上。实验表明，光催化氧化技术处理炼油含碱废水可达到预处理的目的，降解过程具有除臭、除色，快速高效，不产生污泥等优势。     

纳米TiO2粉末的液相法制备及光学吸收特性的研究

采用水解-均相沉淀法,在常温下即可制得纯锐钛型纳米TiO2粉末,对所制得的粉末进行了TEM、XRD、EDS、XPS和UV-VIS分析。结果表明:采用水解-均相沉淀法,通过添加NH4C l和H2SO4可在室温下制得粒径为32nm的纯锐钛型纳米TiO2粉末,并且粉末粒径均匀,尺寸分布较窄;纳米TiO2粉末对波长200~360 nm范围内的紫外线有较好的吸收作用,且吸收较均匀。     

二氧化钛薄膜的制备及光催化性能研究

通过液相沉积法(LPD)在玻璃片表面制备TiO2薄膜,并以甲基橙溶液为污染液,通过探讨制备TiO2薄膜原料的摩尔比例、诱导晶、沉积温度及时间,以及热处理温度及光照时间等因素对甲基橙溶液降解率的影响,得出最佳的降解条件.研究得出:(NH4)2TiF6与H3BO3摩尔比例为1∶1～1∶6,TiO2诱导晶为0～0.1g,沉积温度为25～65℃和沉积时间24h范围内,最佳降解条件为:摩尔比为1∶6,诱导晶为0.06g,沉积温度为55℃,550℃热处理,适当的沉积及光照时间.     

高含量高透明度PS/TiO2纳米复合材料膜的紫外防护性能研究

采用溶剂热法非水合成了粒径小于20 nm的二氧化钛（TiO2）纳米粒子,并用硅烷偶联剂（KH 570）对纳米粒子进行原位修饰以提高粒子在聚苯乙烯（PS）的对二甲苯溶液中的分散性。采用旋涂法制备不同纳米TiO2粒子含量的PS复合材料膜,用紫外可见光光谱仪检测了薄膜的紫外防护性能。结果表明,纳米TiO2的最高含量达到95 %（质量分数,下同）;随着纳米TiO2粒子含量的增加,薄膜的紫外屏蔽性能逐渐增强,同时可见光区的透明度不会线性减少,而是趋于饱和,当纳米TiO2粒子含量达到95 %时,在人眼最敏感的550 nm波长处,依然可以获得82 %的透明度。     

Preparation of TiO2-Pt hybrid nanofibers and their application for sensitive hydrazine detection

The TiO2-Pt hybrid nanofibers with an average dia. 72.6 nm were fabricated by electrospinning poly(vinylpyrrolidone)-ethanol solution containing platinum acetate and titanium tetraisopropoxide, followed by calcination in air at 500 °C for 3 h. High resolution TEM showed that Pt nanoparticles with an average diameter of ～2 nm were well dispersed in the anatase TiO2 nanofibers. Compared to pristine TiO2 nanofibers (average dia. 67.7 nm), the incorporation of Pt nanoparticles into TiO2 nanofibers can greatly enhance the oxidation of hydrazine in neutral solution. The amperometric hydrazine sensor, using the as-prepared TiO2-Pt hybrid nanofibers as the electrochemical catalyst, shows a wide linear range (up to 1.03 mM), a good limit of detection (0.142 μM), and a high sensitivity of 44.42 μA mM(-1) cm(-2). In addition, the excellent anti-interference property, free of matrix effect from real water samples and good reproducibility make the developed hydrazine sensor promising for real applications.     

二氧化钛纳米管阵列制备和光催化降解甲基橙

采用电化学阳极氧化的方法,以氟化铵水溶液为电解液,在纯钛表面制备了TiO2纳米管阵列。以甲基橙为模拟污染物,考察了TiO2纳米管阵列光催化降解效果。结果表明,TiO2纳米管阵列催化降解效果要好于TiO2薄膜电极,60、120和180 min时,降解率分别为56%、88%和100%;而TiO2薄膜电极的降解率分别为43%、76%和91%。在此基础上,考察了阳极氧化电压、氧化时间和焙烧温度对阳极氧化过程的影响规律。结果表明,阳极氧化电压在10～25 V,氧化时间在1～2 h,焙烧温度在500℃时所制备的TiO2纳米管阵列光催化降解性能最好。     

载体对Co-Cu催化剂催化CH4-合成气梯阶转化反应的影响

以钴、铜为活性金属,采用等体积浸渍法制备Co-Cu双金属催化剂,考察了不同载体的Co-Cu双金属催化剂对CH4-合成气梯阶转化直接合成C2+含氧化合物的影响,并进行了XRD、NH3-TPD和H2-TPR表征及相应的分析。实验结果表明,载体对催化剂催化性能有较大的影响,不同载体的催化剂对CH4-合成气两步梯阶转化反应的活性高低顺序为Co-Cu/TiO2＞Co-Cu/Al2O3＞Co-Cu/SiO2,Co-Cu/TiO2催化剂对C2+含氧化合物的选择性为79.9%。这归因于TiO2载体与活性金属Co、Cu之间适宜的相互作用及载体对Co-Cu良好的分散性能。此外,Co-Cu/TiO2催化剂还具有反应所需的表面酸量及适度的中强酸度。