纳米银三角片的光诱导法可控制备及其抗菌活性

采用一种快速高效的光诱导法合成了纳米银三角片,系统地考察了光照时间、柠檬酸钠用量、OH-用量和合成方法对银纳米三角片的合成产率、尖端形貌及其稳定性的影响。研究结果表明,采用光诱导法合成纳米银三角片的最优条件为光照时间3.5 h,反应物物质的量之比n_AgNO3：n_Na3C6H5O7：n_NaBH4=1：10：0.8,OH-浓度0.125 mmol·L^-1,合成出粒径70~80 nm的纳米银三角片,透射电镜和紫外可见分光光度的表征结果表明：光诱导法相对于直接化学还原法制得的纳米银三角片具有较好的微观形态、产率及稳定性。抗菌测试结果表明三角片形态的纳米银比球型颗粒形态的纳米银具有更优异的抗菌性能。     

CoSAPO-34分子筛的合成、表征及其光催化脱氮性能

利用水热合成法,以三乙烯四胺(TETA)为模板剂,正硅酸乙酯、磷酸、氢氧化铝及乙酸钴为原料,合成了CoSAPO-34分子筛。通过扫描电子显微镜(SEM)、粉末X射线衍射(XRD)、热重(TG)、N2吸附-脱附和紫外-可见漫反射光谱(UV-Vis DRS)等方法对合成的分子筛进行表征。以吡啶-正辛烷体系为模拟油品对分子筛催化剂的脱氮效果进行评价,考察了样品的用量、光催化时间及循环催化次数对其脱氮性能的影响。结果表明:当合成原料的物质的量之比为n_(P_2O_5)∶n_(Al_2O_3)∶n_(SiO_2)∶n_(Co)∶n_(TETA)=1∶0.82∶0.26∶0.81∶2.05,在200℃晶化24 h,合成得到粒径约为50μm、仍保持了SAPO-34分子筛的骨架结构、形貌为立方体的Co SAPO-34分子筛,而且该分子筛具有较好的热稳定性。在500 W氙灯光照条件下反应150 min,样品对质量分数为100μg·g-1模拟油品的脱除率达到70%,循环3次光催化脱氮活性基本保持不变。     

米诺地尔分子印迹聚合物的制备与吸附性能

以吸附量为评价指标,筛选米诺地尔分子印迹聚合物的合成条件。结果表明,制备该聚合物的较佳反应条件是V_(甲醇)/V_(乙腈)=1∶3为致孔剂、a-甲基丙烯酸(MAA)为功能单体、n_(米诺地尔)/n_(MAA)/n_(交联剂)=1∶6∶20,采用筛选出的合成条件制备出的分子印迹聚合物,对模板分子有良好的吸附性能。     

Ag/Ag3 PO4等离子体共振光催化剂的制备及其在可见光下的催化性能

以Na_2HPO_4和AgNO_3为原料,通过简单的离子交换法合成Ag_3PO_4,将合成的Ag_3PO_4悬浮在亚甲基蓝溶液中,用500 W的氙灯光照,通过光诱导方法制备Ag/Ag_3PO_(4 )等离子体共振复合光催化剂,以亚甲基蓝的光催化降解来评价其催化性能。利用XRD、XPS、SEM、UV-Vis DRS对催化剂进行表征,结果表明,在亚甲基蓝溶液中的前2小时,Ag_3PO_4表面的Ag~0量随光照时间增长而增加,当Ag~(0 )的含量达到14%后基本保持不变。光催化降解亚甲基蓝实验表明Ag/Ag_3PO_4体系具有高效的催化性能和良好的稳定性;对Ag/Ag_3PO_4体系的光催化机理进行了探讨,可见光区的高吸收归因于沉积在Ag_3PO_4上纳米银的等离子共振效应,同时银的加入使光生电子和光生空穴有效的分离,Ag/Ag_3PO_4体系简易的制备方法和高效稳定的催化性能可以用来在太阳光下降解有机污染物。     

表面活性剂AEO-3对β沸石合成的促进作用

在常规β沸石的水热合成体系中加入非离子型表面活性剂脂肪醇聚氧乙烯醚(AEO-3),按照n_(Al_2O_3)∶n_(SiO_2)∶n_(Na_2O)∶nTEAOH∶n_(H_2O)∶n_(AEO-3)∶n_(C_2H_5OH)=(0.28～1)∶40∶1.55∶10∶640∶(0.45～7.69)∶11.37的配料比,考察其作为助剂对β沸石合成的影响。实验发现,与常规合成体系相比,AEO-3的加入可促进硅铝酸盐溶胶的生成并增加了其均匀化程度,同时增加了产品收率。所合成样品的X射线衍射、N_2和Ar吸附-脱附、扫描电镜、固体核磁和正癸烷吸附的表征结果表明,表面活性剂AEO-3的加入使β沸石的纳米晶粒更加完整与均匀,提高了结晶度和微孔体积,并使得收率提高。所合成的β沸石的骨架硅铝比提高,酸强度增加。另外,AEO-3的加入提高了β沸石结构中的手性多形体A的比例。     

软模板法制备三维花状MgAl-LDH及其吸附性能

采用软模板法,以十二烷基硫酸钠(SDS)为模板剂,经水热合成制得三维花状双金属(Mg Al)氢氧化物(3D-Mg Al LDH)。通过XRD、FT-IR、SEM及TEM等表征手段,研究了原料Mg/Al物质的量之比、SDS浓度及反应时间对产物微观结构和表面形貌的影响规律,并初步探讨了3D-Mg Al LDH的形成机理。结果表明,当n_(Mg)/n_(Al)=2,SDS浓度为0.1 mol·L~(-1),水热反应时间为6 h时,可形成结晶度良好、花球形貌完整,纳米片厚度均一的三维花状LDH。在3D-Mg Al LDH的形成过程中,SDS既以阴离子形态参与LDH形成,又因其类球状胶束特性附着在已形成的LDH表面或边缘诱导LDH纳米片交叉生长形成三维花状。吸附实验表明,3D-Mg Al LDH对非离子型有机污染物具有良好的吸附作用,最大吸附量约为31 mg·g~(-1),去除率达到100%。     

利用介孔分子筛中高度分散的Cu-Co氧化物的高效协同作用提高VOCs的催化消除效率

采用一种改进的胶束辅助合成方法,成功地制备了一系列含铜钴氧化物的x Cuy Co/NS-MS-s介孔分子筛催化剂。以气相甲苯作为VOCs的代表污染物,考察了催化剂对甲苯的去除效果。通过各种表征手段,对催化剂的结构、形貌以及Cu-Co双金属物种的化学状态等物理、化学性质进行了详细的表征。结果表明,当双金属之比控制为n_(Cu)∶n_(Co)=1∶3时,催化剂具有最佳的甲苯催化燃烧活性(甲苯转化率50%时的温度T_(50)=232℃,甲苯转化率99%时的温度T_(99)=239℃)以及良好的稳定性。     

光照纳米银颗粒对葡萄糖生物传感器响应电流的抑制

采用纳米银-壳聚糖复合膜固定葡萄糖氧化酶,构建葡萄糖生物传感器.利用计时电流法对不同光照时间纳米银颗粒组装的酶电极响应电流进行了表征.实验结果表明,光照纳米银颗粒可以抑制葡萄糖生物传感器的响应电流;随着光照时间的延长,纳米银颗粒的抑制作用逐渐增强,当光照时间达到120min时,葡萄糖生物传感器的响应电流最小(-3.953μA/cm²).葡萄糖生物传感器响应电流的抑制可能是由纳米银颗粒表面的Ag⁺离子浓度及表面性能的变化引起的.     

Mn改性Ni/K/MoS2合成低碳醇催化剂反应性能研究

以不同的添加方式在Ni/K/MoS2催化剂中加入Mn助剂，考察其合成醇反应性能。结果表明，Mn/Ni/K/MoS2催化剂具有较好的合成低碳混合醇反应性能。共沉淀法以醋酸锰为前驱体加入0.6%的Mn助剂后，C2+含量，醇时空产率及选择性均明显提高;分步沉淀法使Mn的加入量增加到0.6%，醇时空产率明显增加。以浸渍法按化学计量加入Mn助剂考察其含量对催化剂合成醇性能的影响，当Mn/Mo（原子比）为1∶时，反应条件为315 ℃, 9.5 MPa, 6 000 h－1，醇时空产率和醇选择性分别达到最高值0.338?g/mL·h和69.6%。300 h的稳定性测试结果表明，共沉淀法改性的催化剂具有良好的稳定性。     

生物基水性聚氨酯的制备及性能研究

以甲苯二异氰酸酯(TDI)和二羟甲基丙酸(DMPA)为硬段,丙烯酸松香GMA二元醇(RAG)和聚乙二醇(PEG-1000)为软段,通过预聚体法合成了松香基芳香族型水性聚氨酯(RWPU)。利用红外光谱、X射线衍射分析、热重分析、差示扫描量热分析、静态水接触角等分别表征了RWPU的组成、结构、热性能和耐水性,研究了不同R值(-NCO/-OH摩尔比)、n_(RAG)/n_(PEG-1000)和DMPA用量对RWPU乳液稳定性及涂膜性能的影响。结果表明,成功制备了软硬段具有较好相容性的水性聚氨酯;随着R值的增大,RWPU热分解温度下降,玻璃化转变温度升高;随着DMPA用量的增加,耐水性逐渐减弱;在R=1.5、n_(RAG )/n_(PEG-1000)=17∶3、DMPA的用量为反应单体的11wt.%条件下制备的RWPU树脂综合性能最佳,涂膜光泽度为146.1,铅笔硬度为H,柔韧性为1 mm,附着力为1级,耐冲击强度为50 cm·Kg。     

Exploring the Interactions of Atomic Oxygen on Silver Clusters with Hydrogen

The interactions between Ag_nO^-(n=1-8) and H₂ (or D₂) were explored by combination of the mass spectroscopy experiments and density function theory (DFT) calculations. The experiments found that all oxygen atoms in Ag_nO^-(n=1-8) are inert in the interactions with H₂ or D₂ at the low temperature of 150 K, which is in contrast to their high reactivity with CO under the same condition. These observations are parallel with the preferential oxidation (PROX) of CO in excess hydrogen catalyzed by dispersed silver species in the condensed phase. Possible reaction paths between Ag_nO^-(n=1-8) and H₂ were explored using DFT calculations. The results indicated that adsorption of H₂ on any site of Ag_nO^-(n=1-8) is extremely weak, and oxidation of H₂ by any kind of oxygen in Ag_nO^-(n=1-8) has an apparent barrier strongly dependent on the adsorption style of the "O". These experiments and theoretical results about cluster reactions provided molecule-level insights into the activity of atomic oxygen on real silver catalysts.     

Colorimetric Determination Of Hydrogen Peroxide Based on Localized Surface Plasmon Resonance of Silver Nanoprisms Using a Microchannel Chip

Silver nanoprisms (AgNPrs) have unique optical phenomena due to their localized surface plasmon resonance that results in the extinction of light from the visible to the near-infrared spectral region. In this study, we propose the colorimetric determination of silver nanoprisms in microchannels using a smartphone camera. Image acquisition was performed by capturing an image of the colloidal solution of the silver nanoprisms in the microchannel using the transmitted light. Red, green, and blue chromaticity levels were extracted from the recorded images for further quantification of the silver nanoprisms. This technique was employed for the detection and colorimetric determination of hydrogen peroxide (H₂O₂). Good linearity between the change in the green chromaticity level and concentration of hydrogen peroxide was observed for values from 10 to 300?μM with an R² value of 0.9670. We anticipate that the developed methodology for the quantification of silver nanoprisms and hydrogen peroxide by monitoring the change in color in the images of transmitted light will enhance the development of simple, rapid, and reliable detection systems for quality control in the production of silver nanoprisms as well as in chemical sensor applications.     

Calculation of the Gibbs Energy of the Reaction OH-·(H2O)n-1 + H2O = OH-·(H2O)n by the Monte-Carlo Method

The energy, the Gibbs energy of the reaction OH^-·(H₂O) _{n- 1} + H₂O = OH^-·(H₂O) _n are calculated by the Monte-Carlo method with a large canonical ensemble for n = 1, ..., 20. The ion-waternonpair interaction potential was obtained by numerical fitting of calculated Gibbs energy and entropy of (H₂O)_n clusters (n = 1, ..., 5) to experimental ones. A good fit to experiment both of the internal energy and the Gibbs energy can be obtained in terms of a model allowing for nonpair interaction. It is shown that constructing an ion-water interaction potential without allowance for the entropy factor can lead to considerable errors in the Gibbs energy of cluster formation and in the nucleation rate.     

Synthesis,crystal structure,in vitro anticancer and in vivo acute oral toxicity studies of tetramethylene linked bis-benzimidazolium salts and their respective dinuclear Ag(I)–NHC complexes

The proligands of the series tetramethylenebis(N-n-alkylbenzimidazolium bromide) (where n = 3–10) (1–8) as N-heterocyclic carbene (NHC) precursors have been prepared by reacting the initially synthesized N-n-alkyl benzimidazole with 1,4-dibromobutane in 2 : 1 M ratio. A reaction of Ag₂O with 1–8 resulted in the formation of Ag(I) complexes tetramethylenebis{(N-n-alkylylbenzimidazol-2-ylidene)silver(I)hexafluorophosphate} (9–16), respectively. All the synthesized compounds were characterized by FT-IR, ¹H NMR, ¹³C NMR, atomic absorption and elemental analysis. Single-crystal X-ray diffraction study on tetramethylenebis{(N-n-octylbenzimidazol-2-ylidene)silver(I)hexafluorophosphate} (14) has revealed that the complex exists as a dinuclear compound. All compounds were assessed for their antiproliferation test on human colorectal cancer cell line (HCT 116). Interestingly, increasing the n-alkyl chain length from n = 3 to 10 of the proligands and their respective complexes showed trends in increased cytotoxicity against human colon cancer cell line. Cytotoxicity data showed that tetramethylene linked bis-benzimidazolium salts and their respective dinuclear Ag(I)–NHC complexes can be useful therapeutic agents against colon cancer.     

From mesogens to metallomesogens. Synthesis,characterisation, liquid crystal and luminescent properties

Continuation with our previous investigation which refers to the synthesis of a series of hydrophobic symmetrical azine compounds: 1,2-bis[4-(n-alkoxy)benzylidene]hydrazine (where, n-alkoxy: O(CH₂)_nH, n = 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 16 or 18), a series of hydrophobic asymmetrical azine compounds: [1-(4-propyloxy)-2-(4?-(n-alkoxy))benzylidene]hydrazine (where, n-alkoxy: O(CH₂)_nH, n = 1, 2, 4, 5, 6, 7, 8, 9, 10, 12, 16 or 18) was synthesised following an efficient and practical method. These compounds were synthesised by the condensation reaction of hydrazine hydrate with 4-propyloxybenzaldehyde and appropriately 4-(n-alkoxy)benzaldehydes in acidic medium and ambient conditions (very simple way with no need of any sophisticated techniques). Moreover, two new series of silver(I) complexes based on symmetrical or asymmetrical azines have been synthesised (linear-binuclear type complexes with the general formula [Ag₂(L)(NO₃)₂] were obtained). The organic compounds and their silver(I) complexes were characterised using different techniques: microelemental analysis and spectral data (FTIR, UV–Vis, ¹HNMR, ¹³C{¹H}NMR, 2D ¹H-¹H-COSY, 2D ¹H-¹³C-HSQC and mass spectra) as well as molar conductivity measurements for silver(I) complexes. Liquid crystal behaviour of the prepared compounds were studied using polarised light optical microscopy and confirmed with differential scanning calorimetry and X-ray powder diffraction techniques. The studies revealed that all azine compounds and some of silver(I) complexes are liquid crystal materials. The luminescent properties of all the prepared compounds were also investigated which confirmed that all of these compounds are photo-luminescent in the crystalline solid state and in the mesophase.     

Comparison of catalytic activity and efficiency of hydrogen peroxide utilization for di-iron-containing silicotungstate with those for iron containing complexes and the oxidation of methane and ethane

The Keggin-type di-iron-substituted γ-SiW₁₀{Fe(OH₂)}₂O₃₈ ^6- showed high efficiency of hydrogen peroxide utilization for the oxidation of cyclohexane. The efficiency and catalytic activity greatly depended on the structures of the iron centers. Such a structure dependency of the catalysis is significant and the remarkable catalytic performance of di-iron-substituted polyoxometalate may be related to the catalysis by methane monooxygenase. Not only cyclohexane but also cyclooctane, n-hexane, n-pentane, and adamantane were catalytically oxygenated with high efficiency of hydrogen peroxide utilization. Even methane and ethane were oxidized. It was also demonstrated that the potassium salt of γ-SiW₁₀{Fe(OH₂)}₂O₃₈ ^6- oxidized methane in water.     

银纳米棱镜的形成及其光学性能研究

以有机溶剂作为反应介质,聚合物为稳定剂,通过微波辅助溶液法成功地制备了具有特殊光学性能的银纳米棱镜.利用X射线衍射、透射电子显微镜和紫外-可见光谱等手段跟踪反应过程.结果显示,随着反应的进行,银纳米粒子由10nm左右的球形颗粒逐渐转变为具有规则三角形(或缺角的三角形)形貌的纳米棱镜;同时,紫外-可见吸收峰不但显示出明显的量子尺寸效应,而且吸收峰也由单一的等离子共振吸收峰变为多重的多极吸收峰共同存在,胶体溶液也随之显示出不同的颜色.改变反应物的配比、体系的浓度及无机前驱物都会得到位置和峰形各不相同的吸收曲线,从而得到多彩的纳米银胶体溶液.     

Unusual Rate Enhancement in the Hydroxide-Ion-Catalyzed Cleavage of Acetyl Salicylate Ion (Aspirin Anion) in the Presence of Anionic Micelles

The reaction rate studies on the hydrolytic cleavage of acetyl salicylate ion (AS^-) within the [^-OH] range 0.010-0.025 M reveal AS^- and ^-OH as the reactants. The effects of micelles of sodium dodecyl sulfate (SDS) on observed pseudo-first-order rate constants (k_obs) for the hydrolytic cleavage of AS^- have been studied at different [OH^-]. At a constant [OH^-], the rate constants (k_obs) follow an empirical relationship: k_obs = C + F [SDS]_T where [SDS]_T represents total SDS concentration. The magnitudes of C and F increase with an increase in [OH^-]. These data are explained in terms of the pseudophase model of the micelle.     

Ag3PO4/Ag2S/g-C3N4复合光催化剂的制备与性能

通过沉积法和离子交换法成功地制备了Ag_3PO_4/Ag_2S/g-C_3N_4复合型光催化剂。利用X射线多晶粉末衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)、N_2吸附-脱附等温线、紫外-可见漫反射光谱、荧光光谱等手段对样品进行了表征。通过降解罗丹明B考察其可见光催化活性及稳定性,研究了硫化钠与磷酸银物质的量的比值(n_(Na_2S)/n_(Ag_3PO_4))、g-C_3N_4添加量对所制备复合光催化材料性能的影响,同时对光催化机理进行了探讨。结果表明,随着n_(Na2S)/n_(Ag3PO4)的增加,所得复合催化材料活性先增加后降低;当n_(Na2S)/n_(Ag_3PO_4)为1.5%、g-C_3N_4与Ag_3PO_4的质量比为3∶7时制备的催化剂ASC1.5的光催化活性最好,在可见光照射下,40 min内可将罗丹明B完全降解,且5次循环使用后仍保持较高的催化活性。和Ag_3PO_4相比,Ag_3PO_4/Ag_2S/g-C_3N_4复合型光催化材料的活性与稳定性都得到明显提高,这主要归因于复合催化剂比表面积和孔结构的增加,载流子分离效率的提高。光催化机理研究表明,空穴(h~+)、超氧阴离子自由基(·O~(2-))和羟基自由基(·OH)都是光催化过程中的主要活性物种。三者作用大小依次为:h~+·O~(2-)·OH。