Gold Nanoparticles Confined in Vertically Aligned Silica Nanochannels and Their Electrocatalytic Activity Toward Ascorbic Acid

A facile method of confining gold nanoparticles (AuNPs) in silica nanochannels aligned perpendicularly to an underlying electrode surface is reported. The nanochannel surface carrying a layer of (3‐aminopropyl)triethoxy silane (APTS) displays a strong electrostatic interaction with AuCl₄^?, eventually resulting in the confinement of AuNPs inside the nanochannels after chemical reduction. As‐prepared AuNPs in APTS‐modified mesoporous silica film (APTS‐MSF) are highly dispersed with a narrow size distribution. Furthermore, these AuNPs are free of protecting ligands and exhibit a good electrochemical catalytic activity toward the oxidation of ascorbic acid.     

电沉积Pt-Au双金属催化剂及其对甲酸的电催化研究

以玻碳电极(GCE)为基体, 采用恒电位法制备Pt-Au双金属催化剂. 通过扫描电镜(SEM), X射线能量色散谱(EDX)及电化学方法对催化剂样品进行了表征. SEM结果表明, Pt-Au双金属催化剂的形貌近似球状, 表面粗糙. 循环伏安法和计时电流法的测试结果表明, Au的加入有利于双金属催化剂上甲酸的电催化氧化, 并提高了催化剂对甲酸氧化的抗毒化能力. 而甲酸在催化剂上的氧化机理则通过电化学阻抗技术得到进一步说明. 同时研究了双金属催化剂中Au的不同含量对甲酸氧化的影响, 当 Pt和Au物质的量比为1∶1.803时, Pt-Au/GC催化剂具有最佳的甲酸电催化氧化活性.     

电沉积双金属微粒电极及对甲醇的电催化研究

以循环伏安法在镍铬铁基体上制备了Pt-Ru微粒电极, 用SEM表征该微粒电极的形貌呈球形, 循环伏安法和计时电流法考察了该电极的电化学性能. 结果表明Pt-Ru微粒电极对甲醇的电氧化显示出催化作用, Ru的加入提高了电极的抗中毒能力. 在相同的实验条件下, Pt-Ru微粒电极对甲醇的催化氧化性能高于纯铂电极, 且该电极制作成本十分低廉、操作简便、对环境无污染, 极大减少了贵金属铂的用量, 可用作燃料电池的电极材料.     

以介孔氧化硅薄膜为模板电沉积合成新型纳米结构

首次以不同孔道结构的介孔氧化硅薄膜为模板,采用电化学沉积的方法,合成了金属铜和半导体氧化锌的纳米材料,并对其结构进行了表征．以六方孔道结构的介孔氧化硅模板获得了直径为7nm的金属铜纳米线阵列;以笼状体心立方孔道结构的模板获得了具有哑铃状形貌的铜单质纳米颗粒．对于氧化锌纳米结构,电化学沉积过程使得氧化锌完全填充氧化硅模板的孔道,分别得到了具有六方和体心立方介孔结构的Zn0/SiO2纳米复合物薄膜．     

介孔SiO2负载的纳米金及其催化应用

金（Au）的催化作用已成为催化领域的前沿研究课题。本文综述了近年来采用不同方法制备介孔二氧化硅(MCM-41, MCM-48, SBA-15)负载的纳米Au催化剂以及在CO低温氧化、环己烯加氢和环己烷氧化等反应中的催化作用。讨论了影响纳米Au催化剂活性的相关因素, 包括载体的种类、表面性质、Au纳米颗粒的尺寸、分散度以及稳定性等。最后对各种制备纳米Au的方法进行了总结。     

混合模板法制备螺旋纳米结构二氧化硅

用凝胶剂高氯酸环（L-11-（N-甲基咪唑）十一烷基天冬酰胺-L-苯丙酰胺）（11mim ClO4）和十六烷基三甲基氯化铵（CTAC）作模板剂,经溶胶-凝胶过程,制备纳米结构二氧化硅．使用冷场发射扫描电镜（FESEM）,表征了多种反应条件下样品的形貌和表面结构．结果表明,通过调节CTAC和凝胶剂的质量比,可以得到螺旋介孔二氧化硅纳米纤维,其长度为数百纳米,孔径为3．0nm．     

When Mesoporous Silica Meets the Alkaline Polyelectrolyte: A Controllable Synthesis of Functional and Hollow Nanostructures with a Porous Shell

An efficient and environment friendly surface‐protected etching method by using mesoporous silica as a template and alkaline polyelectrolyte as both the protecting and etching agent was developed to prepare a SiO₂ nanotube with a porous shell. The polyelectrolytes attached to the template not only create a localized alkaline environment, but also effectively protect the silica surface, whereas the mesopore channels accelerate the diffusion of etchant throughout the template, all of which facilitate the formation of hollow structures in a fully controllable way. By tuning the etching power and protecting ability of the polyelectrolyte, the rigidity and porosity of products can be precisely manipulated. It is inspiring that various alkaline polyelectrolytes including polypeptide and dextran derivative can be used for the etching process, so that the porous and hollow nanostructures are born with positively charged and biocompatible surface as well as abundant amino groups for further coupling, which make them potential capsules for drug delivery and probes for imaging and detection. The protective etching process can also be extended to the preparation of yolk‐shell super structures with functional cores, or porous nanoparticle assemblies with their individual characteristics maintained.     

硅铝基微孔/介孔复合分子筛的制备与应用

本文对具有多级孔道和双重酸性的硅铝基微孔/介孔复合分子筛的制备及应用进展进行了评述,重点讨论了微孔沸石晶体结构的存在对产物酸性、结构稳定性的贡献,强调了制备途径对合成微孔/介孔功能复合材料的简捷性、有效性,探讨了此类催化材料的发展前景。     

电化学合成Pt-Au复合催化剂及其对甲醇的电催化氧化

在ITO导电玻璃上, 采用循环伏安法制备Pt-Au复合催化剂. 通过扫描电镜(SEM), X射线能量色散谱(EDX), X射线衍射(XRD)及其电化学方法对催化剂样品进行了表征. SEM结果表明, Pt-Au复合催化剂的形貌近似球状粒子. 循环伏安法和计时电流法的测试结果表明, 复合催化剂中Au的加入有利于甲醇的电催化氧化, 并提高了Pt对甲醇氧化的抗毒化能力. 同时研究了复合催化剂中Au的不同含量对甲醇氧化的影响, 结果表明, 当 Pt和Au物质的量比为1.07∶1时, Pt-Au/ITO催化剂具有最佳的甲醇电催化氧化活性.     

合成条件对径向有序介孔二氧化硅中空亚微米球的形貌和结构的影响

本文以硬模板与软模板结合的双模板方法(十六烷基三甲基溴化铵(CTAB)为介孔模板,聚苯乙烯(PS)球为中空模板),通过自组装制备出有良好分离性和单分散性且具有径向介孔的二氧化硅中空亚微米球.研究表明CTAB、TEOS的用量,催化剂的种类对二氧化硅中空亚微米球的形貌、壁厚、产品纯度等都有很大的影响.在保持其它实验条件不变的情况下,通过分别单独调节CTAB和TEOS的用量或同时调节CTAB和TEOS的用量,得出最佳原料配比是:TEOS/CTAB/NH3/乙醇/水的摩尔比是1:0.27:9.8:304:2955,TEOS/聚苯乙烯球的质量比是4/1.催化剂的种类对中空亚微米球的形貌也有较大影响,当NaOH(浓度为1 mol/L)的用量为0.05—0.10 mL时,生成由小粒子聚集而成的亚微米球;随着NaOH用量增大到0.10—0.20 mL,小粒子逐渐粘合在一起,亚微米球表面逐渐变光滑;进一步增大NaOH用量为0.20—0.30 mL则导致杂质小粒子的出现.在实验结果和文献报道的基础上,讨论并提出了径向有序介孔二氧化硅中空亚微米球的形成机理.     

Realization of Walnut‐Shaped Particles with Macro‐/Mesoporous Open Channels through Pore Architecture Manipulation and Their Use in Electrocatalytic Oxygen Reduction

Herein we report a simple dual‐soft‐template approach to prepare walnut‐shaped macro‐/mesoporous polydopamine particles with diameter of ca. 270 nm, highly accessible bicontinuous channels and wide pore size distribution from ca. 20 nm to ca. 95 nm. This approach provides great opportunities to tailor the soft template‐directed assembly processes and generate various polydopamine particles with controllable mesophase curvature. Walnut‐shaped mesoporous carbon particles with large open mesochannels in the range of ca. 13 nm to ca. 50 nm can be fabricated by subsequent thermal treatment under nitrogen atmosphere. Lastly, we demonstrate that the as‐derived walnut‐shaped carbon particles manifest enhanced electrocatalytic performance for oxygen reduction reaction in alkaline electrolyte.     

中空介孔硅球原位接枝聚苯胺及其pH响应性药物控制释放行为

通过原位化学氧化聚合的方法,在中空介孔二氧化硅纳米粒子表面成功接枝上了聚苯胺(HMSsPANI).借助透射电镜(TEM)、红外光谱(FTIR)、紫外可见吸收光谱(UV-Vis)、氮气脱附吸附等温测试(BET)、热失重(TGA)、小角粉末衍射(XRD)和zeta电位测试等手段表征了其结构性质.通过循环伏安曲线研究,发现HMSs-PANI分散体系在不同pH条件下具有电化学活性的转变性质,证实了HMSs-PANI在酸性条件下能够进行有效的掺杂从而具有电化学活性.最后用HMSs-PANI来负载抗癌药物盐酸阿霉素(DOX),其展现了良好的酸性pH可控释放行为,在pH=7.4时,22 h后仅有15%的药物累计释放量.在pH=5的条件下,22 h后累计释放量达到44%,而在pH=4条件且同样时间之下,释放量为60%.总之,合成的HMSs-PANI酸响应药物控制释放体系在药物传输领域具有潜在应用.     

原位合成的活性脲醛树脂作为模板剂制备二氧化硅介孔材料

利用酸性条件下正硅酸乙酯的水解和脲醛树脂的聚合反应同时一步原位进行的方法合成了二氧化硅复合粉体(包括核壳微球结构和网状结构)和块体凝胶材料. 液氮吸附BET分析结果证明复合材料焙烧后得到的二氧化硅孔径分布均匀, 大小在介孔范围内. 改变反应性单体尿素. 甲醛及正硅酸乙酯等的初始浓度可对二氧化硅块体材料的孔径大小进行调节. 扫描电子显微镜观测结果显示, 随着原料单体初始浓度的变化复合粉体材料的微米级形貌可以是多孔网状结构或核壳结构. 从红外光谱和差热分析的结果推测, 高甲醛/尿素摩尔比[n(甲醛)∶n(尿素)≥2]条件下形成的支链脲醛树脂可作为块体二氧化硅理想的孔结构导向剂.     

复合介孔二氧化硅膜的制备及应用

复合介孔二氧化硅膜是近十年来发展起来的一种具有独特孔中孔结构的新型膜材料。该材料以多孔膜（无机多孔膜或者有机多孔膜）为硬模板,以表面活性剂为结构导向剂,通过溶胶-凝胶等方法将介孔二氧化硅材料组装在多孔膜的孔道中制备而成。由于其具有不同于传统介孔二氧化硅膜材料的一些独特结构和性能,并在分离、吸附和催化等领域具有广泛的应用前景,引起了人们广泛的关注。本文主要就复合介孔二氧化硅膜的制备方法,特别是近几年内其在纳滤、纳米材料的模板合成、酶的固定、传感器、反应器以及药物释放等方面最新的应用研究进展进行论述,同时对这类新型的复合介孔二氧化硅膜材料在合成和应用方面存在的问题进行了分析和总结,并对其发展前景作了展望。     

Self‐Immolative Linkers as Caps for the Design of Gated Silica Mesoporous Supports

A new hybrid material based on sulforhodamine B dye‐loaded silica mesoporous nanoparticles capped with a self‐immolative gate has been synthesized and characterized. The gated material's controlled release behavior is monitored under different pH conditions. Under acidic and neutral conditions, a low level of dye release is detected. However, at slightly basic pH, significant dye release occurs owing to deprotonation of the phenol moiety in the capping molecule, which results in its disassembly.     

Chitosan‐Capped Mesoporous Silica Nanoparticles as pH‐Responsive Nanocarriers for Controlled Drug Release

Herein, we present a straightforward synthesis of pH‐responsive chitosan‐capped mesoporous silica nanoparticles (MSNs). These MCM‐41‐type MSNs could be used as nanocapsules to accommodate guest molecules. Subsequently, (3‐glycidyloxypropyl)trimethoxysilane was grafted onto the surface of the MSNs, which served as a bridge to link between MSNs and chitosan, which is ubiquitous in nature and commercially available. Owing to the pH‐responsive and biocompatible features of chitosan, the loading and release of an anti‐cancer drug, doxorubicin hydrochloride, were carried out in vitro, in which the composite chitosan‐capped MSNs (CS‐MSNs) showed excellent environmental response. As the pH value of the media decreased, the degree of drug release correspondingly increased. Moreover, thanks to the perfect biocompatibility of chitosan, the CS‐MSNs exhibited lower cytotoxicity than that of the naked MSNs in an MTT assay. In addition, the in vitro kill potency against MCF‐7 breast‐cancer cells was enhanced over time, as well as with increasing concentration of the drug‐loaded CS‐MSNs. These results indicate that CS‐MSNs are promising candidates for pH‐responsive drug delivery in cancer therapy.     

Usefulness of Mesoporous Silica as a Template for the Preparation of Bundles of Bi Nanowires with Precisely Controlled Diameter Below 10 nm

The reduction of the diameter of Bi nanowires below 10 nm has been an important target because of the theoretical prediction with regard to significant enhancement in thermoelectric performance by size reduction. In this study, we have demonstrated the usefulness of mesoporous silica with tunable pore size as a template for the preparation of thin Bi nanowires with diameters below 10 nm. Bi was deposited within the templates through a liquid phase deposition using hexane and 1,1,3,3‐tetramethyldisiloxane as a solvent and reducing agent, respectively. Bundles of thin Bi nanowires with non‐crystalline frameworks were successfully obtained after the template removal. The diameter was precisely controlled between about 6 nm and 9 nm. The judicious choices of mesoporous silica and deposition conditions are critical for the successful preparation. The reliable formation of such thin Bi nanowires reported here opens up exciting new possibilities.