基于碳酸钙-金纳米粒子无机杂化复合物固定硫堇的新方法及其在过氧化氢传感器中的应用

通过静电作用,经碳酸钙-金纳米粒子(CaCO3-AuNPs)无机杂化复合物实现了电活性物质硫堇(Th)在金电极表面的有效固定.AuNPs静电吸附到CaCO3微球表面形成CaCO3-AuNPs无机杂化复合物,该杂化复合物具有微孔结构、大的表面积和好的生物相容性,使得Th的固定量和稳定性大大提高.探讨了Th修饰电极在过氧化...     

金纳米粒子组装体的连续离散型纳米结构控制

采用柠檬酸钠还原氯金酸的方法,制备出粒径均一的金纳米粒子(AuNPs),通过加入二水合双(对-磺酰苯基)苯基膦化二钾盐(BSPP),增强了AuNPs体系的分散性与稳定性.选用直径为15和40nm的AuNPs,用不同序列巯基修饰的单链DNA连接到其表面,通过DNA链的杂交,形成不同结构的金纳米粒子组装体.通过改变加入DNA延长连接单元的比例,可以控制金纳米粒子组装体具有连续离散型的1∶1,2∶1和3∶1纳米结构.     

油基-金纳米流体的制备及热稳定性

分别采用N-十六烷基-N-(羟乙基)-N,N-二甲基溴化铵(CHDAB)和丁烷-1,4-二(N-十六烷基-N,N-二甲基溴化铵)(G16-4-16)2种阳离子表面活性剂作为金属表面修饰剂, 在石油醚/正丁醇/水混合体系中用KBH₄ 还原HAuCl₄制备出亲油性纳米金. 其中, 双子表面活性剂G16-4-16显示出更好的包裹分散作用, 其包裹的纳米金粒径分布范围较窄, 平均粒径为5.2 nm. 将该纳米金颗粒分散在液态烷烃、 甲苯和长链烷基醇等溶剂中可制成稳定的油基纳米流体. 采用紫外-可见光谱法跟踪热稳定性随时间的变化, 结果表明, 该纳米流体显示了较好的热稳定性, 在130 ℃稳定时间达20 h. 采用点热源法测定了该纳米流体的导热系数, 结果表明, 50 ℃时添加质量分数1.5%的纳米金可以使其导热系数增大约17%.     

钯纳米粒子的形貌可控合成与催化性能（英文）

借助于一种全新的表面活性剂N,N-dimethyloctadecylammonium bromide acetate sodium(OTAB-Na),成功实现了对小尺寸钯纳米粒子微结构的控制。通过对合成条件的微扰,高度均匀且分散性良好的枝化结构和凹面体结构的钯纳米粒子被成功地制备。催化测试(利用氨硼烷作为氢化试剂来还原4-硝基苯酚为4-胺基苯酚)发现,钯纳米粒子的催化活性与其微观纳米结构相关,其中枝化结构的钯纳米粒子表现出了更为突出的催化性能。     

钯纳米粒子的形貌可控合成与催化性能

借助于一种全新的表面活性剂N,N-dimethyloctadecylammonium bromide acetate sodium（OTAB-Na）,成功实现了对小尺寸钯纳米粒子微结构的控制。通过对合成条件的微扰,高度均匀且分散性良好的枝化结构和凹面体结构的钯纳米粒子被成功地制备。催化测试（利用氨硼烷作为氢化试剂来还原4-硝基苯酚为4-胺基苯酚）发现,钯纳米粒子的催化活性与其微观纳米结构相关,其中枝化结构的钯纳米粒子表现出了更为突出的催化性能。     

钯纳米粒子的形貌可控合成与催化性能

借助于一种全新的表面活性剂N,N-dimethyloctadecylammonium bromide acetate sodium（OTAB-Na）,成功实现了对小尺寸钯纳米粒子微结构的控制。通过对合成条件的微扰,高度均匀且分散性良好的枝化结构和凹面体结构的钯纳米粒子被成功地制备。催化测试（利用氨硼烷作为氢化试剂来还原4-硝基苯酚为4-胺基苯酚）发现,钯纳米粒子的催化活性与其微观纳米结构相关,其中枝化结构的钯纳米粒子表现出了更为突出的催化性能。     

表面覆盖型AuNPs@PNIPAM复合粒子的制备及催化性能

金纳米粒子(AuNPs)表面能高,在水中极易团聚,使其应用受限.本文采用物理共混法,将带有正电荷的温敏聚(N-异丙基丙烯酰胺)(PNIPAM)微凝胶与带负电荷的AuNPs混合,经自组装制备了微凝胶表面覆盖AuNPs的有机-金属复合粒子AuNPs@PNIPAM.该复合粒子不仅具有很好的分散稳定性,而且其粒子的分散液具有温度比色性,在25℃→50℃→25℃的温度变化过程中呈现“红→紫→红”的可逆颜色变化.通过对硝基苯酚(4-NP)的还原反应,研究了复合粒子的催化性能.结果表明,复合粒子具有受温度调控的催化能力,随温度升高催化性能呈现先降后升的趋势.与文献报道的类似材料相比, AuNPs@PNIPAM复合粒子同时具有温度比色性和催化性能.     

磁性碳基上金纳米颗粒的原位生长及其催化应用

我们提出了一种绿色、新型的,用于原位生长均一的Au纳米粒子的方法,在还原氧化石墨烯纳米片表面使用聚乙烯亚胺和3,4-二羟基苯甲醛作为连接剂将还原的金纳米粒子和强耦合的Fe_3O_4纳米粒子组装,得到了Au/Fe_3O_4/PEI/rGO纳米复合材料,其能在水溶液中高效地催化NaBH_4还原降解工业污水中的常见污染物4-硝基苯酚,而且具有很好的催化剂稳定性,10个催化循环之后仍对4-硝基苯酚保持有92%以上的催化降解率。另外,Au/Fe_3O_4/PEI/rGO催化剂可以用磁铁进行分离,方便其回收再利用和对产物进行纯化。这些特征使这种复合纳米材料可以作为一种新型,高效的催化剂可能在环境保护、工业催化和新能源领域有一定的应用前景。     

多金核二氧化铈空心球用于硝基苯酚催化加氢

催化剂的微观结构在催化还原反应、有机物氧化反应及有机物转化反应中起着关键作用。本文利用无模板方法合成了多金核中空二氧化铈微球催化剂。将制备好的二氧化铈中空微球浸渍到一定浓度的氯金酸溶液中,然后多次洗涤除去表面吸附的氯金酸离子,最后通过硼氢化钠还原制成中空氧化铈微球包覆的多金核的核壳结构催化剂。将该核壳结构材料用于硝基苯酚加氢反应与金纳米粒子及氧化铈微球相比,多金核中空二氧化铈核壳结构表现出优越的活性和稳定性。通过这种浸渍洗涤再还原的简单方法合成的多金核二氧化铈催化剂有望应用于生物医药和能源环境等领域。     

多金核二氧化铈空心球用于硝基苯酚催化加氢（英文）

催化剂的微观结构在催化还原反应、有机物氧化反应及有机物转化反应中起着关键作用.本文利用无模板方法合成了多金核中空二氧化铈微球催化剂.将制备好的二氧化铈中空微球浸渍到一定浓度的氯金酸溶液中,然后多次洗涤除去表面吸附的氯金酸离子,最后通过硼氢化钠还原制成中空氧化铈微球包覆的多金核的核壳结构催化剂.将该核壳结构材料用于硝基苯酚加氢反应与金纳米粒子及氧化铈微球相比,多金核中空二氧化铈核壳结构表现出优越的活性和稳定性.通过这种浸渍洗涤再还原的简单方法合成的多金核二氧化铈催化剂有望应用于生物医药和能源环境等领域.     

Colorimetric detection of Fe3+ ions using pyrophosphate functionalized gold nanoparticles

A sensitive, selective colorimetric Fe(3+) detection method has been developed by using pyrophosphate functionalized gold nanoparticles (P(2)O(7)(4-)-AuNPs). Gold nanoparticles were prepared by reducing HAuCl(4) with sodium borohydride, in the presence of Na(4)P(2)O(7). IR spectra suggested that pyrophosphates were capped on the surface of the gold nanoparticles. Aggregation of P(2)O(7)(4-)-AuNPs was induced immediately in the presence of Fe(3+) ions, yielding a color change from pink to violet. This Fe(3+)-induced aggregation of P(2)O(7)(4-)-AuNPs was monitored using first the naked eye and then UV-vis spectroscopy with a detection limit of 5.6 μM. The P(2)O(7)(4-)-AuNPs bound by Fe(3+) showed excellent selectivity compared to other metal ions (Ca(2+), Cd(2+), Co(2+), Fe(2+), Hg(2+), K(+), Mg(2+), Mn(2+), Na(+), Ni(2+), Pb(2+), and Zn(2+)). The best detection of Fe(3+) was achieved in a pH range from 3 to 9. In addition, the P(2)O(7)(4-)-AuNPs were also used to detect Fe(3+) in lake water samples, with low interference.     

Mixed aggregate formation in gemini surfactant/1,2-dialkyl-sn-glycero-3-phosphoethanolamine systems

An evaluation of the physical interactions between gemini surfactants, DNA, and 1,2-dialkyl-sn-glycero-3-phosphoethanolamine helper lipid is presented in this work. Complexation between gemini surfactants and DNA was first investigated using surface tensiometry where the surface tension profiles obtained were found to be consistent with those typically observed for mixed surfactant-polymer systems; that is, there is a synergistic lowering of the surface tension, followed by a first (CAC) and second (CMC) break point in the plot. The surfactant alkyl tail length was observed to exhibit a significant effect on the CAC, thus demonstrating the importance of hydrophobic interactions during complexation between gemini surfactants and DNA. The second study presented is an investigation of the mixing interactions between gemini surfactants and DOPE using Clint's, Rubingh's, and Motomura's theories for mixed micellar formation. The mixing interactions between the 16-3-16/16-7-16/16-12-16/16-7NH-16 gemini surfactants and DOPE were observed to be antagonistic, where the strength of antagonism was found to be dependent upon the gemini surfactant spacer group and the solution composition.     

Influence of Amine‐Based Cationic Gemini Surfactants on Catalytic Activity of α‐Chymotrypsin

The α‐chymotrypsin activity was tested in aqueous media with the presence of novel cationic amine–based gemini surfactant, with different spacer chain lengths and head group size, and also compared with the cationic cetyltrimethylammonium bromide (CTAB) and cetyltriphenylphosphonium bromide (CTPB) surfactants and aqueous buffer only. The p‐nitrophenyl acetate (PNPA) hydrolysis rate was monitored in the presence of the surfactant concentration at 30°C. Most of these gemini surfactants gave higher catalytic activity as compared to cationic CTAB and CTPB. The highest superactivity was measured in the presence of gemini 16‐12‐16, [dodecanediyl‐1,12‐bis(cetyldimethylammonium bromide)] surfactant at pH 7.5. The catalytic reaction follows the Michaelis–Menten mechanism. The catalytic rate constants, k_cat, show the same profile that the catalytic affinity; K_M being enhanced with increasing space chain length. The results are favorable for considering that the amine‐based gemini surfactant influences more than both the aqueous and cationic micellar media.     

Synthesis of hierarchical Polystyrene/Polyaniline@Au nanostructures of different surface states and studies of their catalytic properties

We synthesized hierarchical Polystyrene/Polyaniline@Au(PS/PANI@Au) catalysts through a seeded swelling polymerization and in-situ reduction procedure. PS/PANI@Au catalysts possess a core of PS as seed and template, a PANI shell with fibers and uniform gold nanoparticles on the surface. The configuration changes of the PANI chains resulting from the doping/ dedoping procedure led to various loading amounts of Au nanoparticles. Reduction of 4-nitrophenol was chosen as the probe reaction to evaluate the catalytic activity of supported Au nanocatalysts. The catalytic results indicated that dedoping treatment of the PS/PANI supports provides stronger coordinative ability to metal nanoparticles as well as more –N= groups, which results in a better catalytic performance towards the reduction of 4-nitrophenol.     

两相催化体系中双子表面活性剂对1-十二烯氢甲酰化反应的助催化作用

合成了几种具有刚性连接基团的双子表面活性剂,研究了它们在Rh-TPPTS体系中催化长链烯烃氢甲酰化反应中的助催化作用.结果表明,在水/有机两相催化体系中,新型双子表面活性剂的助催化作用比单链表面活性剂CTAB更好,在较低的表面活性剂浓度下能得到较高的反应转化率.这归因于此类表面活性剂有较低的cmc,降低界面张力的能力和对1-十二烯的增溶能力比CTAB更强.     

Comparative studies on electrogenerated chemiluminescence of luminol on gold nanoparticle modified electrodes

Comparative studies on the electrogenerated chemiluminescence (ECL) behavior of luminol on various electrodes modified with gold nanoparticles of different size were carried out in neutral solution by conventional cyclic voltammetry (CV). The results demonstrated that the gold nanoparticle modified electrodes could generate strong luminol ECL in neutral pH conditions. The catalytic performance of gold nanoparticle modified electrodes on luminol ECL depended not only on the gold nanoparticles but also on the substrate. Gold electrode and glassy carbon electrode were the most suitable substrates for the self-assembly of gold nanoparticles. Moreover, the gold nanoparticle modified gold and glassy carbon electrode had satisfying stability and reproducibility and did not need tedious pretreatment of electrode surface before each measurement. It was also found that luminol ECL behavior depended on the size of gold nanoparticles. The most intense ECL signals were obtained on a 16-nm-diameter gold nanoparticle modified electrode. The modified electrode prepared by the self-assembly method exhibited much better catalytic effect on luminol ECL than that prepared by the electrically deposited method. The ECL behavior of luminol on a gold nanoparticle self-assembled gold electrode was also investigated by other transient-state electrochemical techniques, such as chronoamperometry, differential pulse voltammetry, normal pulse voltammetry, and square wave voltammetry. The strongest ECL intensity was obtained under square wave voltammetric condition.     

Surfactant (bi)layers on gold nanorods

Gold nanorods in aqueous solution are generally surrounded by surfactants or capping agents. This is crucial for anisotropic growth during synthesis and for their final stability in solution. When CTAB is used, a bilayer has been evidenced from analytical methods even though no direct morphological characterization of the precise thickness and compactness has been reported. The type of surfactant layer is also relevant to understand the marked difference in further self-assembling properties of gold nanorods as experienced using 16-EO(1)-16 gemini surfactant instead of CTAB. To obtain a direct measure of the thickness of the surfactant layer on gold nanorods synthesized by the seeded growth method, we coupled TEM, SAXS, and SANS experiments for the two different cases, CTAB and gemini 16-EO(1)-16. Despite the strong residual signal from micelles in excess, it can be concluded that the thickness is imposed by the chain length of the surfactant and corresponds to a bilayer with partial interdigitation.     

Synthesis and Characterization of Self-Assembling Some Thiol Surfactants on Gold Nanoparticles

The purpose of this work is to study the self-assembling of some synthesized thiol surfactants namely (mercaptopropane-, mercaptohexane-, mercaptooctane-, and mercaptodecane sodium sulfonate) on the fabricated gold nanoparticles. The self-assembling of these surfactants on gold nanoparticles characterized using different techniques such as FTIR spectroscopy, UV spectroscopy, and transmission electron microscopy (TEM). Spectroscopic evidence suggests that the synthesized thiol surfactants have been attached to the gold nanoparticles. The effect of self-assembling of these surfactants on the size of the gold nanoparticles was studied using TEM images. The growth of the gold nanoparticles was investigated with respect to the increase of alkyl chain in the synthesized thiol surfactants. The results show that the stabilization of gold nanoparticles was affected by the increase in alkyl chain length of these surfactants. The effect of gold nanoparticles on the interfacial tension and the emulsion stability of these surfactants with crude oil was studied.     

Green preparation of hollow mesoporous silica nanosphere inside-loaded gold nanoparticles and the catalytic activity

In this work, an active nano-catalyst with gold nanoparticles loaded in hollow mesoporous silica nanospheres (HMSNs/Au) was prepared by a one-pot sol-gel method, in which gold ions were loaded in hollow mesoporous silica spheres followed by sodium alginate reduction. The characterization of the HMSNs/Au were determined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), N₂ adsorption–desorption isotherms (BET). The high catalytic activity of HMSNs/Au, denoted as apparent turn-over frequency (TOF), was detected by UV-Vis spectrophotometer for the catalytic reduction of 4-nitrophenol (74.5 h^?1) and 2-nitrophenol (108.7 h^?1) in the presence of sodium borohydride solution due to the small gold nanoparticles size and overall exposure of active sites. It is expected that this ecofriendly approach to prepare inorganic composited nanoparticles as high active catalysts based on hollow mesoporous materials was a promising platform for loading noble metal nanoparticles.