正离子Gemini表面活性剂/负离子聚电解质相互作用的研究

摘要 采用荧光探针法和电导法研究了正离子偶联表面活性剂(C₁₂H₂₅(CH₃)₂N-(CH₂)₆-N(CH₃)₂C₁₂H₂₅•2Br) (12-6-12• 2Br^－)和带相反电荷聚电解质聚丙烯酸钠(NaPA)的相互作用, 结果表明: 由于静电相互作用, 12-6-12•2Br^－和NaPA之间可以形成类胶束或复合物. 对比十二烷基三甲基溴化铵(DTMAB)与NaPA复配体系的荧光光谱, 发现偶联表面活性剂与NaPA的相互作用强于传统表面活性剂. 此外, 还研究了盐和醇对偶联表面活性剂/聚丙烯酸钠的复配体系微极性的影响, 发现盐和醇对表面活性剂在聚电解质上形成类胶束和复合物的溶解都有一定的促进作用.     

亚微米级多刺状星形氧化铜的制备

在阳离子gemini表面活性剂[C₁₆H₃₃(CH₃)₂N^＋(CH₂)₄N^＋(CH₃)₂C₁₆H₃₃]•2Br^－ (16-4-16)存在条件下, 以六次甲基四胺为沉淀剂, 利用水热合成法制备了大量多刺状星形亚微米级氧化铜. 用X射线衍射(XRD), X射线光电子能谱(XPS), 扫描电子显微镜(SEM)和透射电子显微镜(TEM)等多种手段对制备产物的表征结果表明, 所得产物是具有单斜结构多刺状星形氧化铜. 考察了表面活性剂浓度、温度以及铜源对产物物相及其形貌的影响.     

溶剂热插层法制备荧光石墨相氮化碳量子点及其在Fe3+检测中的应用

利用溶剂热法, 基于氢氧化钾的插层作用制备了荧光氮化碳量子点(g-C₃N₄ QDs). 所获得的氮化碳量子点具有良好的水溶性和荧光稳定性. 透射电子显微镜(TEM)照片显示, 氮化碳量子点的粒径约为2.3 nm; X射线光电子能谱(XPS)和红外光谱(FTIR)结果表明, 氮化碳量子点表面存在大量的亲水基团; 荧光发射光谱(PL)结果表明, 氮化碳量子点具有激发波长依赖性. 基于三价铁离子(Fe³⁺)对荧光氮化碳量子点荧光的猝灭现象, 构建了一种用于检测Fe³⁺的荧光传感器, 在Fe³⁺浓度为5~100 μmol/L范围内, 检测体系表现出良好的线性关系, 检出限约为0.5 μmol/L, 实现了对Fe³⁺的高效、 灵敏、 选择性检测.     

In2O3修饰三维纳米花MoSx构建S型异质结用于高效光催化产氢

形貌控制和异质结构建是提升光催化剂性能的有效策略。本文采用In₂O₃修饰三维纳米花MoS_x并构建S型异质结,为电子的传输提供了特殊的转移途径。通过合理调控In₂O₃的负载量,MoS_x/In₂O₃的最佳产氢速率能够达到6704.2 μmol∙g⁻¹∙h⁻¹,是纯MoS_x的1.8倍。采用荧光光谱和电化学测试证实复合材料中内部电子和空穴对的分离效率得到了有效的提升,并利用紫外漫反射测试和羟基自由基实验推测了析氢机理。     

Ag2S基近红外II区荧光量子点的水相合成优化探究

具有近红外II区荧光的Ag₂S量子点(QDs)因具有带隙窄、Stokes位移大及光稳定性好等优点而在生物成像领域具有广阔应用前景. 然而, 传统有机相合成的Ag₂S量子点水溶性与生物相容性较差, 而水相合成Ag₂S量子点的荧光又很难到近红外II区, 这严重制约了Ag₂S量子点的生物医学应用推广. 因此, 优化探究具有近红外II区荧光发射的Ag₂S基量子点的水相合成方法具有重要意义. 采用核掺杂ZnS、表面阳离子(Zn²⁺)改性以及调控表面配体制备出一系列Ag₂S基量子点, 发现核掺杂和表面阳离子改性均使Ag₂S基量子点的荧光呈现剂量依赖性蓝移; 而将表面配体由树枝状短链(Captopril)更换为长直链(11-巯基十一烷酸, MUA)时, Ag₂S基量子点的发射峰红移至1105 nm(近红外II区)且半峰宽更窄. 本研究发现, 相比核掺杂和表面阳离子改性, 优化表面配体更容易在水相中制备出具有近红外II区荧光的Ag₂S基量子点. 本工作为近红外荧光量子点的水相合成及优化提供了基础研究数据.     

碳氟醇对阳离子表面活性剂表面活性及胶团反离子结合度的影响

用表面张力及电动势法研究了C₁₀H₂₁N(CH₃)3Br、C₁₂H₂₅N(CH₃)3Br与C₃F₇CH₂OH混合水溶液的表面与胶团性质。结果表明,对于阳离子表面活性剂,C₃F₇CH₂OH的加入一方面增加表面活性,另一方面降低胶团反离子结合度。后者不同于阴离子表面活性剂/C₃F₇CH₂OH混合体系,可归因于C₃F₇CH₂OH略有酸性,因而具备一些类似阴离子表面活性剂的性质。     

碳氟表面活性剂与碳氢表面活性剂混合水溶液的表面吸附与胶团形成(Ⅳ)——非离子-非离子体系

测定了25℃不同比例的C₁₀F₁₉O(C₂H₄O)₉H与C₈H₁₇C₆H₄O(C₂H₄O)₁₀H混合水溶液的表面张力,研究混合水溶液的表面性质与胶团形成。用两种不同方法计算在表面上的表面成份、分子之间相互作用参数(β_σ)。结果表明,在非离子型碳氟和碳氢表面活性剂混合水溶液中,两种表面活性剂基本上各自形成胶团;表面分子相互作用参数皆为正值;表明此混合体系中碳氟链与碳氢链之间互疏作用的存在。     

表面活性剂对CdSe量子点荧光性能的影响

通过添加不同类型的表面活性剂在水相中制备了CdSe量子点。用透射电子显微镜(TEM)、X射线衍射(XRD)、X-射线光电子能谱(XPS)对其进行了表征,并用紫外-可见(UV-Vis)和荧光(PL)分光光度法研究了不同类型的表面活性剂对CdSe量子点吸收光谱和荧光光谱的影响。结果表明,加入长链的非离子型和阴离子型表面活性剂制备的CdSe量子点颗粒只有几个纳米,分散性好,量子点的荧光强度也有明显的增强,而加入阳离子表面活性剂制备的量子点颗粒团聚明显,其荧光出现淬灭。     

双官能Fe3O4/CdSe/CdS荧光磁性复合物的制备和表征

采用化学共沉淀法, 以FeCl₂•4H₂O和FeC1₃•6H₂O为原料制备磁性Fe₃O₄纳米颗粒(MNPs), 采用氨基酸对其进行修饰使其表面连上氨基. 用巯基乙酸作为稳定剂合成了水溶性的CdSe/CdS量子点, 并利用偶联剂1-乙基-3-(3-二氨丙基)碳二亚胺盐酸盐(EDC)和N-羟基琥珀酰亚胺(NHS)连接氨基修饰的Fe₃O₄和带有羧基的CdSe/CdS, 成功制备了Fe₃O₄/CdSe/CdS荧光磁性纳米颗粒. 该荧光磁性纳米复合物保留了CdSe/CdS量子点优异的荧光特性, 平均粒径在40 nm左右; 磁化曲线表明此纳米复合物具有超顺磁性. 这种双官能复合纳米颗粒有望成为新型荧光磁性双标记复合微粒而广泛应用于免疫检测、荧光追踪、磁性分离等领域.     

氨基功能化石墨烯量子点表面缺陷钝化及其发光增强

通过酸氧化法将氧化石墨烯进一步“切割”制备石墨烯量子点（GQDs）,在100℃水热条件下,用氨水处理石墨烯量子点制备得到氨基功能化石墨烯量子点（N-GQDs）。傅里叶变换红外光谱证明NH₃可以有效地进攻环氧基碳和羧基碳,形成羟胺和酰胺基。原子力显微镜结果表明NH₃不仅能够有助于产生更小的量子点,还对石墨烯纳米片有致孔作用。氨基功能化之后,由于C-O-C相关的n-π^*跃迁受到抑制,N-GQDs发光具有更弱的激发波长依赖性,并使其荧光量子产率从0.3%提高至9.6%。时间分辨发光光谱表明,相比含氧基团,含氮基团相关的局域电子激发态具有更长的荧光寿命和更弱的发射光谱依赖性。     

富氧空位的非晶氧化铜高选择性电催化还原CO2制乙烯（英文）

过量化石能源的消耗导致大气中的二氧化碳含量不断上升,由此引发包括温室效应在内的环境问题。对此,常温常压下的电催化二氧化碳还原手段为制备高附加值的化工原料和实现碳循环提供了一种很有前景的技术储备。在众多的二氧化碳还原产物中,碳氢化合物尤其是乙烯,它作为塑料和其他化工产品的重要原料受到广泛的关注。电催化二氧化碳还原制乙烯工艺不仅可适配于现有的生产设备也可作为取代目前工业化的裂解方法。近年来,研究者们为了开发高效的电催化二氧化碳还原制乙烯催化剂开展了大量的研究。不过值得注意的是,大部分研究集中于铜基材料。尽管目前研究者取得了很多成果,但仍缺少可高选择性产乙烯的二氧化碳还原催化剂。如何设计出可活化二氧化碳分子,同时对*CO和*COH中间物有强吸附能力的催化剂是研究难点。针对此问题,本文中通过真空蒸镀的方法制备出一种富氧空位的非晶氧化铜纳米薄膜催化剂。受益于纳米薄膜的构建和氧空位的引入,该催化剂可快速进行电荷和物质的交换,并利于二氧化碳分子的吸附及优化还原中间产物的亲和力,进而表现出优异的电催化二氧化碳制乙烯的性能。结果表明,在加有0.1 mol·L^-1碳酸氢钾溶液的H型电...     

皂荚素的表面活性及其二元体系的热力学研究

通过表面张力的测定研究了皂荚素(GS)的表面活性及其热力学性质随温度的变化.测定了皂荚素分别与十二烷基磺酸钠、十二烷基聚氧乙烯醚硫酸钠、全氟辛酸钠、十二烷基脂肪醇聚氧乙烯(9)醚、辛基酚聚氧乙烯(10)醚及十六烷基三甲基溴化铵等复配的表面张力-浓度对数关系(γ～lgc)曲线,并用二维晶格模型及正规溶液理论计算了含皂荚素的二元表面活性剂溶液表面吸附层的组成、分子相互作用参数及分子交换能.结果表明,皂荚素主要呈现非离子表面活性剂的性质,与阳离子表面活性剂复配呈微弱的离子性.复配后分子交换能均小于零,复配增效.增效顺序为GS/阳离子>GS/非离子>GS/阴离子(表面活性剂复配体系).     

液相剥离法大规模制备锑烯量子点

本工作采用超声辅助液相剥离法制备锑烯量子点,研究了在180 W、10 h的超声工艺条件下,分别以H_2O、C_2H_5OH、N-甲基吡咯烷酮(NMP)为剥离溶剂得到的样品形貌。以分散浓度及稳定性为标准,评估了三种溶剂在锑烯量子点制备中的优劣。结果表明,锑烯样品在NMP中分散浓度最高且最为稳定。透射电子显微镜(TEM)的结果显示,只有NMP中的样品在形貌上呈现出来的是量子点,而其他两种溶剂中得到的样品主要是锑烯纳米片,所以NMP是最适合锑烯量子点制备的溶剂。此外,我们还标定了以上三种溶剂中锑烯样品浓度与比浊度的标准曲线,从而可以通过比浊法方便地测定锑烯分散液的浓度。     

贫PbI2基体的胶体量子点固体用于高效红外太阳能电池(英文)

胶体量子点(CQD)具有优异的红外光吸收能力和光谱可调特性,是用于制备高效太阳能电池最有前途的红外光电材料之一。然而,以醋酸铵(AA)为添加剂的液相配体交换会导致CQD固体中产生宽带隙PbI₂基质,其将作为电荷传输势垒,在很大程度上影响了CQD太阳能电池(CQDSC)中载流子的提取,从而影响了光伏性能。本文报道利用二甲基碘化铵(DMAI)调节CQD配体交换过程,使载流子在CQD固体中的传输势垒大幅降低。通过对CQD固体进行全面的表征和理论计算,充分揭示了DMAI和CQD之间的相互作用。结果表明,通过DMAI调节CQD配体交换过程,使CQD固体均匀堆积,提高了载流子输运性能,并且陷阱辅助复合受到显著抑制。因此,CQDSC器件中的载流子提取得到了大幅提高,能量转换效率(PCE)比用AA制备的CQDSC器件提高了17.8%。此工作为调控CQD表面化学特性提供了新的研究思路,并为降低CQD固体中载流子输运的势垒提供了可行的方法。     

Solution behaviour of a formate capped surfactant—the oxidation product of an alcohol ethoxylate

The solution behaviour has been investigated for an alcohol ethoxylate terminated with a formic acid ester. This compound has previously been reported to be an important degradation product in the auto-oxidation of alcohol ethoxylates. In this work we have investigated the solution behaviour of the formic acid ester surfactant C₁₂H₂₅(OCH₂CH₂)₄OCHO (C12E4---OCHO). The pure formate was found to be sparsely soluble in water with no clear point at 0.1%. The critical micelle concentration was found to be 129 μM at 35°C, compared to 50 μM for the parent surfactant C₁₂H₂₅(OCH₂CH₂)₅OH (C12E5). To mimic the behaviour of the oxidised surfactant, the formate was mixed in different ratios with C12E5 and the cloud point, surface tension and critical micelle concentration (cmc) of these mixtures were studied. The gradual increase of formate was found to shift the cloud point and isotropic regions to lower temperatures. The cmc of the mixture was found to be lower than for the pure surfactant. The favourable interaction was analysed according to the non-ideal model by Rubingh and the interaction parameter, β, was determined to be −4±0.53, which is unusually large for a mixture of two non-ionic surfactants. These results indicate that the reduction of cloud point observed during oxidation of non-ionic surfactants can in part be attributed to the formation of formate esters.     

液滴在超疏水植物叶面的沉积：实验和分子动力学模拟

农药液滴在靶标植物叶面的动态沉积对于提高农药利用率具有重要的意义,特别是在超疏水植物叶面的动态沉积。在本文中,我们利用生物基表面活性剂和甘油之间的氢键作用来增强液滴在超疏水植物叶面的有效沉积。在较低浓度的山梨醇-烷基胺表面活性剂溶液中,添加0.001%的甘油,可有效抑制液滴在不同超疏水/疏水植物叶片表面的弹跳和飞溅行为。结果表明,甘油的加入并没有显著改变山梨醇-烷基胺表面活性剂溶液的表面张力、粘度和聚集体的形态。核磁共振波谱(DOSY)显示,甘油加速了山梨醇-烷基胺表面活性剂分子的扩散速度。利用分子动力学模拟,对山梨醇-烷基胺表面活性剂/甘油体系的能量演化及表面活性剂相对于固体表面距离的分布进行了研究。这项目工作不仅为抑制液滴在植物叶面的弹跳飞溅提供了一种建设性的方法,而且为选择农用表面活性剂提供了理论基础。     

铜基串联催化剂电催化CO2还原的研究进展

Through the combustion of fossil fuels and other human activities, large amounts of CO₂ gas have been emitted into the atmosphere, causing many environmental problems, such as the greenhouse effect and global warming. Thus, developing and utilizing renewable clean energy is crucial to reduce CO₂ emission and achieve carbon neutrality. The electrochemical CO₂ reduction reaction (CO₂RR) has been considered as an effective approach to obtain high value-added chemicals and fuels, which can store intermittent renewable energy and achieve the artificial carbon cycle. In addition, due to its multiple advantages, such as mild reaction conditions, tunable products, and simple implementation, electrochemical CO₂RR has attracted extensive attention. Electrochemical CO₂RR involves multiple electron–proton transfer steps to obtain multitudinous products, such as C₁ products (CO, HCOOH, CH₄, etc.) and C₂ products (C₂H₄, C₂H₅OH, etc.). The intermediates, among which ^*CO is usually identified as the key intermediate, and reaction pathways of different products intersect, resulting in an extremely complex reaction mechanism. Currently, copper has been widely proven to be the only metal catalyst that can efficiently reduce CO₂ to hydrocarbons and oxygenates due to its suitable adsorption energy for ^*CO. However, the low product selectivity, poor stability, and high overpotential of pure Cu hinder its use for the production of industrial-grade multi-carbon products. Tandem catalysts with multiple types of active sites can sequentially reduce CO₂ molecules into desired products. When loaded onto a co-catalyst that can efficiently convert CO₂ to ^*CO (such as Au and Ag), Cu acts as an electron donor owing to its high electrochemical potential. ^*CO species generated from the substrate can spillover onto the surface of electron-poor Cu due to the stronger adsorption and be further reduced to C₂₊ products. The use of Cu-based tandem catalysts for electrochemical CO₂RR is a promising strategy for improving the performance of CO₂RR and thus, has become a research hotspot in recent years. In this review, we first introduce the reaction routes and tandem mechanisms of electrochemical CO₂RR. Then, we systematically summarize the recent research progress of Cu-based tandem catalysts for electrochemical CO₂RR, including Cu-based metallic materials (alloys, heterojunction, and core-shell structures) as well as Cu-based framework materials, carbon materials, and polymer-modified materials. Importantly, the preparation methods of various Cu-based tandem catalysts and their structure–activity relationship in CO₂RR are discussed and analyzed in detail. Finally, the challenges and opportunities of the rational design and controllable synthesis of advanced tandem catalysts for electrochemical CO₂RR are proposed.     

含有酰胺基或酯基的可降解阳离子Gemini表面活性剂在水溶液中的聚集行为

In the last thirty years, Gemini surfactants with various structures have been designed, synthesized, and demonstrated to show superior physicochemical properties. However, the utilization of non-degradable surfactants, including these Gemini surfactants, poses a threat to the environment; hence, degradable Gemini surfactants are desirable. Herein, biodegradable cationic Gemini surfactants with amide or ester groups in the hydrophobic chains or the spacer were synthesized. A monomeric surfactant containing an amide group and a Gemini surfactant with amide groups both in the hydrophobic chains and the spacer were synthesized for comparison. The effects of amide group location on the aggregation behavior of Gemini surfactants were studied systematically. The differences between the Gemini surfactants with amide groups and Gemini surfactants with ester groups were evaluated by comparing their aggregation behavior and hydrogen bonding formation. The Gemini surfactants with amide groups (C₁₂A-C_n-AC₁₂) in the chains showed much larger exothermic ΔH_mic and more negative ΔG_mic values than those of the corresponding monomeric surfactant C₁₂A; besides, their critical micelle concentration (cmc) was more than one order of magnitude lower than that of C₁₂A. The amide groups located in the hydrophobic alkyl chains promoted hydrogen bonding formation and self-assembly of the Gemini surfactants C₁₂A-C_n-AC₁₂. Moreover, ¹H NMR spectra revealed that the co-effect of a short spacer and hydrogen bonding leads to slow exchange of the C₁₂A-C₂-AC₁₂ molecules between the monomer and the aggregate. For the Gemini surfactant series C₁₂-AC_nA-C₁₂, the amide groups notably increased the spacer length, and largest cmc value and smallest exothermic ΔH_mic value were observed for C₁₂-AC₂A-C₁₂ instead of C₁₂-AC₆A-C₁₂. In C₁₂-AC₁₂A-C₁₂, the spacer was long and sufficiently flexible to adopt a "U"-shaped conformation above the cmc, and it acted as the hydrophobic part of the surfactant, as confirmed by ¹H NMR spectra. Among the Gemini surfactant with amide groups in both the spacer and the hydrophobic alkyl chains, C₁₂A-AC₆A-AC₁₂ had a smaller cmc and I₁/I₃ ratio as well as more exothermic ΔH_mic values than those of C₁₂A-C₆-AC₁₂ and C₁₂-AC₆A-C₁₂. ¹H NMR spectra indicated that an ester-alcohol structural equilibrium exists during aggregation for the Gemini surfactants with ester groups. In addition, the Gemini surfactants with ester groups formed water-mediated hydrogen bonds in the aggregates. This water-mediated hydrogen bonding between ester groups was weaker than the direct hydrogen bonding between amide groups. Therefore, the Gemini surfactants with ester groups, C₁₂E-C₆-EC₁₂ and C₁₂-EC₆E-C₁₂, exhibited lower surface activity, a larger micelle ionization degree, higher micropolarity, and smaller exothermic ΔH_mic and less negative ΔG_mic values than their counterparts with amide groups, C₁₂A-C₆-AC₁₂ and C₁₂-AC₆A-C₁₂.     

新型(4-HBA)SbX5·H2O类钙钛矿单晶及其卤素结构对发光特性的调控(英文)

发光材料因其在照明、显示、成像等方面的广泛应用而备受关注。作为新兴发光材料之一,钙钛矿类材料的研究及报道较多。其中,铅基钙钛矿的研究取得了巨大进展,光致发光量子产率(PLQY)几乎达到了100%。然而,基于铅基钙钛矿化学毒性和低稳定性,在实际应用过程中需要特殊的封装,因而提高了生产成本并限制了其实际应用领域。被广泛关注的锡基钙钛矿的荧光量子产率几乎能达到90%,但Sn²⁺易氧化成Sn⁴⁺,在空气中极不稳定。相较于铅基钙钛矿和锡基钙钛矿,锑基钙钛矿的低化学毒性、高热稳定性等优点突出。此外,锑基钙钛矿的光学性能在过去几年中也取得了很大的进展,有望突破传统钙钛矿应用的局限。在此,我们报道了一系列新型单晶(4-HBA)SbX₅·H₂O (4-HBA为4-羟基苄胺缩写,X为Cl或Br)。利用溶剂热法可制备高质量的(4-HBA)SbBr₅·H₂O、(4-HBA)SbBr₃Cl₂·H₂O和(4-HBA)S...