酸的种类和浓度对有序介孔二氧化硅形貌和孔结构的影响

以三嵌段共聚物聚氧乙烯-聚氧丙烯-聚氧乙烯(PEO-PPO-PEO)为模板剂,正硅酸乙酯为无机硅源,HCl、HNO3、H2SO4及H3PO4四种酸为酸性介质,采用水热法合成有序介孔分子筛SBA-15。通过扫描电镜(SEM)、透射电镜(TEM)、X射线衍射(XRD)、N2吸附-脱附等手段对产物的形貌和结构进行分析。结果表明:控制合成母液中H+浓度在一定范围时,HCl、HNO3、H2SO4、H3PO4四种介质中合成出的产品分别为"麦穗"状、"铜钱"状、长程连续"糖块"状和高度分散"糖块"状;在酸种类相同条件下,酸浓度对孔道的大小、微孔含量、孔壁厚度等孔道结构参数有一定影响,但酸浓度对孔道的影响要远小于酸种类的影响。     

燃料电池用碳—现状和今后动态

一、引言从近期能源需求增加趋势及资源有限这一观点来看,开发新能源和有效利用能源是全球所期待的。就“优化地球”这句话来说,保护好地球环境一直是能源开发的重要条件。与社会需要相适应,太阳能发电、风力发电等新能源的开发以及改善汽车燃料消耗量为代表的能源有效利用正在世界各地得到大力发展。用各种新型电池发电或者贮蓄电力是上     

碳材料表面积和孔结构的评价

碳材料表面积和孔结构的评价ＥＬＦｕｌｌｅｒ．Ｊｒｅｔａｌ一、引言惰性气体（Ｎ２、Ａｒ、Ｈｅ等）高温吸附提供了一种表面积和孔结构（尺寸、状态以及分布）的检测方法，经典的ＢＥＴ分析方法（１）不能用来检测微孔（＜２ｎｍ）材料的表面积。因为微孔凝聚作用比单分...     

有序介孔碳材料的制备及应用

有序介孔碳材料因具有较高的比表面积、均匀的孔径分布、有序的孔道结构排列等特性,成为催化、吸附、分离和电化学等领域的研究及应用热点。这里主要介绍了有序介孔碳的两种主要制备方法硬模板法和软模板法,以及其在催化、吸附及电化学等领域中的应用。     

新型碳材料作为DMFC催化剂载体的研究进展

综述了新型碳材料作为直接甲醇燃料电池(DMFC)催化剂载体的研究进展,包括纳米碳材料(如碳纳米管、碳纳米纤维、碳纳米盘、富勒烯碳纳米簇等)和介孔碳材料.新型碳材料负载催化剂的活性都高于传统炭黑负载催化剂,将在DMFC中得到广泛应用.     

有序介孔二氧化钛粉体研究进展

主要综述了高度有序六方相和立方相孔道结构介孔二氧化钛以及具有低有序蠕虫状孔道结构介孔二氧化钛的制备方法及其结构特征。总结了后处理法、模板剂脱除法在制备稳定、具有有序介孔和锐钛矿相孔壁的介孔二氧化钛粉体中的应用,指出采用直接合成法制备孔壁结晶的介孔二氧化钛原粉,之后用萃取法脱除模板剂并用钛酸异丙酯蒸气增强骨架,将是得到高稳定性有序介孔二氧化钛材料的良好途径。     

过渡金属体系有序介孔材料研究进展

过渡金属体系有序介孔材料在催化、光、电、磁等领域有着硅基介孔材料无法比拟的优越特性.详细地介绍了过渡金属体系有序介孔材料的合成和机理,简要地介绍了其应用.     

有序介孔碳材料的表面改性及电化学性能研究

选用HNO3对有序介孔碳材料进行表面改性。通过红外光谱、氮气吸-脱附等测试手段对介孔碳(OMC)和硝酸改性介孔碳(OMC-H)的结构进行表征。采用循环伏安、恒流充放电、交流阻抗等测试比较OMC和OMC-H的电化学性能。结果表明,改性后OMC-H的孔结构发生了变化,OMC的介孔孔径增大,比表面积和孔体积减小。同时,改性也改善了超级电容器的电化学性能。OMC-H单电极在1 m V/s的比电容为262 F/g,高于OMC单电极的比电容(205 F/g)。改性后OMC-H电容器的电荷转移阻抗明显减小。OMC-H电容器欧姆电压降明显小于OMC,表明硝酸改性后介孔碳电极的等效串联内阻减小。改性后OMCH电容器充放电1 500次以后,比电容趋于稳定在58F/g,相比改性前OMC电容器的49 F/g有明显的增加。     

碳球/有序介孔碳复合涂层的制备及其防护性能

以可溶性酚醛树脂为碳前驱体,三嵌段共聚物F127为模板剂,碳球为填充相,经旋涂及溶剂蒸发诱导自组装,在不锈钢基体上构筑了具有高疏水性的碳球/有序介孔碳微纳米复合涂层.进一步利用PT-FE进行表面氯化修饰,获得了超疏水性能,润湿角达142°.扫描电子显微镜显示该复合涂层具有微米级褶皱/纳米级介孔孔道的复合结构.在模拟的海...     

有序介孔碳纳米材料的合成及载药系统构建研究进展

有序介孔碳纳米材料(OMCNs)因具有高的比表面积、有序的介观结构和良好的生物相容性,在药物缓释方面应用广泛。介绍并对比分析了硬、软模板法合成OMCNs的相关研究,综述了基于OMCNs构建载药系统,尤其是具有响应性释药和靶向释药特性的载药系统的研究进展。     

有序多孔炭材料的研究进展

有序多孔炭因其结构规则、易于功能化和模型化,在化学工业、信息通讯、生物技术、环境能源等领域具有重要应用意义。分别从有序微孔、有序介孔和有序大孔3个方面,阐述了制备方法、特点及应用等研究的进展情况,展望了其发展趋势。     

The use of a dynamic hydrogen electrode as an electrochemical tool to evaluate plasma activated carbon as electrocatalyst support for direct methanol fuel cell

The objectives of this study were to functionalize the carbon black surface by chemically introducing oxygenated groups using plasma technology. This should enable a better interaction of the carbon support with the metallic catalyst nanoparticles, hindering posterior support particle agglomeration and preventing loss of active surface. PtRu/C nanoparticles were anchored on the carbon supports by the impregnation method and direct reduction with hydrazine. Physical characterization of the materials was carried out using energy dispersive X-ray analysis and transmission electron microscopy. The screen printing technique was used to produce membrane electrode assemblies for single cell tests in methanol/air (DMFC). Tests were carried out using the dynamic hydrogen electrode as an electrochemical tool to evaluate the anode and cathode behavior separately.     

双模板结构导向剂制备有序介孔炭

以间苯二酚/甲醛制备的酚醛树脂为碳前躯体,三嵌段共聚物F127和P123作为主辅结构导向剂,采用有机-有机自组装的方法制备有序介孔炭(Ordered mesoporous carbons,简称OMCs)。采用X射线衍射仪、透射电镜和N2吸/脱附手段对所制OMCs进行表征,研究了反应时间以及主辅模板剂的比例对介孔孔道结构的影响。结果表明,随着反应时间从24h延长至72 h,介孔炭有序性先增后减;当主辅模板剂F127/P123摩尔比为0.002 7∶0.002 7时,所得介孔炭有序性较好,为P6mm型孔道结构,介孔孔容和比表面积分别为0.59 cm3/g和640.34 m2/g,平均孔径为3.68 nm.     

Purification of catalytically produced carbon nanotubes for use as support for fuel cell cathode Pt catalyst

A purification method based on HCl treatment under reflux was employed for purification of carbon nanotube (CNT) samples, obtained by the electric discharge method utilizing Zr(Co_0.5Ni_0.5)₂, Ce₃(Co_0.5Ni_0.5)₂ and Ce(Co_0.5Ni_0.5)₅ as catalysts. Raman Spectroscopy provided information on the SWCNT presence in the untreated samples. Scanning Electron Microscopy (SEM) showed CNT with different diameters and lengths. Different acid treatment conditions were employed and the best results were achieved for HCl 3 mol/L aqueous solution during 24 h reflux. Transmission Electron Microscopy (TEM) images, associated with EDS, revealed the catalyst removal from the original sample and the presence of other carbon structures near the CNT formation. CNT acid functionalization for Pt nanoparticles dispersion was successful, resulting in a homogeneously dispersed system, as seen in TEM images. Temperature Programmed Oxidation (TPO) analysis of the raw and purified samples indicated that after purification there are three different carbon species present on the purified material, each one showing a different behavior towards O₂ oxidation.     

Rational design of hierarchically porous Fe-N-doped carbon as efficient electrocatalyst for oxygen reduction reaction and Zn-air batteries

The rational design and construction of hierarchically porous nanostructure for oxygen reduction reaction (ORR) electrocatalysts is crucial to facilitate the exposure of accessible active sites and promote the mass/electron transfer under the gas-solid-liquid triple-phase condition. Herein, an ingenious method through the pyrolysis of creative polyvinylimidazole coordination with Zn/Fe salt precursors is developed to fabricate hierarchically porous Fe-N-doped carbon framework as efficient ORR electrocatalyst. The volatilization of Zn species combined with the nanoscale Kirkendall effect of Fe dopants during the pyrolysis build the hierarchical micro-, meso-, and macroporous nanostructure with a high specific surface area (1,586 m²·g⁻¹), which provide sufficient exposed active sites and multiscale mass/charge transport channels. The optimized electrocatalyst exhibits superior ORR activity and robust stability in both alkaline and acidic electrolytes. The Zn-air battery fabricated by such attractive electrocatalyst as air cathode displays a higher peak power density than that of Pt/C-based Zn-air battery, suggesting the great potential of this electrocatalyst for Zn-air batteries.

     

Green and low-cost materials as carbon source for the synthesis of hierarchical porous carbons

Hierarchical porous carbons (HPCs) were successfully synthesized using green and relatively low-cost materials as carbon source. The template of the macro- and large meso-pores was nickel hydroxide obtained from the reaction between sodium hydroxide and nickel nitrate, while the micro- and small meso-pores were formed during the dissipation of the gases produced in the reaction process. Different carbon sources were used for the formation of HPCs, and sucrose proved to be the best which had a Brunauer–Emmett–Teller (BET) surface area of 829 m²/g. Besides, a possible mechanism for the formation of HPCs was hypothesized.     

具有有序宏观结构纳米碳纤维的制备及其性能应用

以CH4为碳源,金属Ni为催化剂,采用化学气相沉积法(CVD)在有序宏观基体材料(SiO2纤维,Al2O3纤维)上制备出纳米碳纤维。利用场发射扫描电镜(FE-SEM)、透射电镜(TEM)、拉曼光谱(Raman)以及热重分析(TG)对产物进行了微观形貌和结构的检测。结果表明,所制备的纳米碳纤维具有取向性,能够在有序宏观基体材料上形成致密有序的纳米碳纤维层;与Al2O3纤维相比,SiO2纤维更易于生成高质量的纳米碳纤维;所制备的纳米碳纤维遵循顶端生长模式。此外,采用纳米碳纤维作模板可以原位合成出具有有序宏观结构的纳米LaMnO3,它能明显降低碳黑颗粒的起燃温度,具有潜在的应用前景。     

石油系新型炭材料的研发现状和发展趋势

主要介绍了几种石油系新型炭材料 ,如中间相沥青、中间相沥青炭微球、碳纤维及其复合材料、针状焦、活性炭的研发现状和发展趋势 ,并对独山子石化公司生产的几种石油沥青、石油渣油进行了组成分析比较 ,对石油系渣油制备新型炭材料的可能性进行了分析     

Synthesis and characterization of sub-10 nm Platinum Hollow Spheres as electrocatalyst of direct methanol fuel cell

Platinum Hollow Spheres (PHSs) with diameters less than 10 nm were successfully synthesized by using Co as a sacrificial template and H2PtCl6 as an oxidizing agent at 95 degrees C. The formation of PHSs at this temperature was not affected by citrate reduction and mainly depended on the pH. The results of transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analysis demonstrated that the platinum hollow sphere was mainly constructed by fcc (face cubic center) platinum with tiny crystallites on the shell. The performance of PHSs for methanol electro-oxidation was evaluated and compared with commercial E-TEK platinum black. Electrochemical measurement by cyclic voltammetry (CV) demonstrated that the electrochemical surface area of PHSs was about twice higher than E-TEK platinum black. Therefore, the synthesized PHSs had higher electrocatalytic activity for methanol electro-oxidation.