柔性锌镍/铝层状双羟基/碳纤维复合材料的电化学制备及光电催化性能（英文）

本文采用电化学方法,制备了一种便于回收和分离的柔性锌镍/铝层状双羟基/碳纤维(Zn Ni/Al-LDHs/CFs)复合材料.采用X射线衍射、红外光谱、场发射扫描电镜、电感耦合等离子体原子发射光谱和电化学阻抗光谱技术表征了Zn Ni/Al-LDHs/CFs复合材料的结构、形貌和光电催化性能.与单独使用Zn/Al-LDHs/CFs作为光催化剂或Ni/Al-LDHs/CFs作为电催化剂相比较,Zn Ni/Al-LDHs/CFs复合材料显示了良好的光-电双功能催化特性,既可被用作乙醇和甲醇氧化的电催化剂,也可光电协同催化2,6-二氯苯酚降解.     

金属-空气电池阴极双功能催化剂研究进展

可充电金属-空气电池因具有超高的能量密度被认为是最有发展前景的能源存储与转换装置之一.阴极电化学氧还原/生成反应缓慢动力学是影响金属-空气电池性能的关键因素,因此其充放电过程需要双功能催化剂进行催化.在此我们详细论述了近年来开发的新型双功能催化剂,包括贵金属、碳材料、过渡金属氧化物和复合材料.其中,强耦合过渡金属氧化物/纳米碳复合物成为新一代具有高催化活性的氧催化材料.最后,基于目前所存在的问题提出了几个未来可能的研究方向.     

Cu@Pt/MWCNTs-MnO2电催化剂的制备及电催化性能研究

通过浸渍还原法,以乙二醇作为还原剂,以H2PtCl6 6H2O作为Pt的前驱体制备了Cu@Pt/MWCNTs核壳型电催化剂;通过水热法,以KMnO4和Mn(NO3)2作为锰源制备了α-MnO2和β-MnO2,并把Cu@Pt/MWCNTs核壳型电催化剂与二氧化锰进行掺杂制得Cu@Pt/MWCNTs-MnO2复合材料.利用XRD,SEM,TEM对复合材料的结构和形貌进行表征,利用循环伏安测试曲线和阴极极化曲线等电化学测试方法对电催化剂的性能进行测试.结果表明,电催化剂中Cu@Pt纳米颗粒为核壳型,粒径为6～8 nm,MnO2的晶型为α-MnO2和β-MnO2;另外,Cu@Pt/MWCNTs-MnO2复合材料具有良好的催化性能,其中Cu@Pt/MWCNTs-β-MnO2电催化剂的电化学性能较好,具有较大的电化学活性面积,为71.1 m2 g-1,同时对MnO2促进氧还原的机理进行了初步探讨.     

一种三叶草型氧化铝/碳纳米纤维复合材料的制备及表征

采用催化化学气相沉积法, 以Ni为催化剂、乙烯作为碳源, 制备了三叶草型氧化铝/碳纳米纤维复合材料, 并通过N2物理吸附、扫描电子显微镜、X射线衍射分析和强度测试对氧化铝/碳纳米纤维复合材料的形貌和物理性能进行了表征. 结果表明, 三叶草型氧化铝表面生长了碳纳米纤维层, 两者紧密结合, 形成的氧化铝/碳纳米纤维复合材料具有较高的比表面积(>187 m2·g-1)和孔体积(>0.24 cm3·g-1), 孔道直径在3-10 nm 的孔体积超过总孔体积的85%, 颗粒的侧压强度大于6 N·mm-1, 可以满足工业催化剂载体对强度的要求. 复合材料是一种有良好的工业应用前景的中孔催化材料, 其中碳纳米纤维层的厚度可通过催化剂Ni负载量和生长时间的调节加以控制.     

双功能催化体系制备聚丙烯/蒙脱土复合材料

为了制备聚丙烯/蒙脱土纳米复合材料,将Brookhart型的乙烯齐聚催化剂负载于有机蒙脱土片层间,进一步与丙烯聚合茂金属催化剂进行复配得到双功能催化体系。采用这种双功能催化剂体系通过催化乙烯齐聚得到α-烯烃/蒙脱土的齐聚产物,进一步将丙烯与这种齐聚产物共聚,合成了一系列结构不同的聚丙烯/蒙脱土纳米复合材料。通过气相色谱、X射线衍射(XRD)分析得出蒙脱土负载的铁系催化剂催化乙烯齐聚产物是以C_4~C_(16)为主的α-烯烃,蒙脱土以片层形式分散于齐聚产物的甲苯溶液中。研究了蒙脱土负载的铁系催化剂与共聚催化剂复配催化乙烯齐聚以及丙烯与齐聚产物共聚合的情况。通过XRD、透射电镜、差示量热分析、凝胶渗透色谱分析表征可知,蒙脱土以纳米片层剥离的形式均匀分散于聚丙烯基体中,聚丙烯/复合材料的结晶温度比纯聚丙烯有所下降,所得聚丙烯基体分子量在8.1×10~4~17.1×10~4g/mo L。     

热处理对甲醇电氧化催化剂PtRu/C性能的影响

采用非离子表面活性剂Triton X-100作为稳定剂制备了催化甲醇电氧化反应的PtRu/C催化剂, 研究了热处理温度对催化剂的组成、结构、形貌和活性的影响. 利用循环伏安法研究了PtRu/C催化剂催化甲醇电氧化的活性, 用热重和差热分析(TG-DTA)、X射线能量色散谱(EDX)、X射线衍射(XRD)、X射线光电子能谱(XPS)和透射电子显微镜(TEM)对PtRu/C催化剂进行了表征. 研究结果表明, 热处理对PtRu/C催化剂粒子的大小、分布和Pt的氧化态有重要的作用. 在350 ℃下热处理的催化剂显示了最好的催化甲醇电氧化的性能, 由Triton X-100作为稳定剂制备的PtRu/C催化剂最适宜的热处理温度是350 ℃.     

反应pH值对微波法合成的Mo修饰的Pt/C催化剂结构和乙醇电氧化催化性能的影响

通过调节微波反应溶液的pH值合成了一系列Mo修饰的Pt/C催化剂并用于乙醇的电氧化催化反应.利用X射线衍射(XRD)、透射电子显微镜(TEM)及X射线光电子能谱(XPS)对催化剂的晶型结构、微观形貌、粒径尺寸和表面电子结构进行了表征,并采用循环伏安法(CV)、计时电流法(CA)和电化学阻抗谱(EIS)对催化剂的乙醇电氧化催化性能进行了测试.结果表明,碱性环境有利于催化剂组分在碳载体上的均匀分布,pH值为14时制得的催化剂组分颗粒尺寸最小,且分布最均匀.该催化剂不仅表现出了最大的有效电化学比表面积和最高的乙醇电氧化催化活性,而且具有最稳定的乙醇氧化催化性能.     

Cu(PPh3)2BH4作还原剂制备PtCu/C催化剂催化烯烃硅氢 加成反应研究

采用湿法浸渍, Cu(PPh3)2BH4作为还原剂制备了负载型PtCu/C双金属催化剂, Pt∶Cu原子比为0.5～2.0. 用于苯乙烯与三乙氧基硅烷加成反应, Cu元素的引入使Pt/C催化剂的催化性能得到提高, 表现出比Speier催化剂、Karestedt催化剂和Pt/C催化剂更好的β-加成产物选择性. 催化直链烯烃与三乙氧基硅烷加成反应表现出优良的催化性能, 并且催化剂可重复使用.     

La1-xSrxCoO3(x=0,0.2,0.4,0.6,0.8)钙钛矿型氧化物的催化性能及改性

通过溶胶-凝胶法制备出A位Sr掺杂的钙钛矿型氧化物La_(1-x)Sr_xCoO_3(x=0,0.2,0.4,0.6,0.8),并将其作为催化剂应用于双功能氧电极中。测试结果表明,A位Sr的掺杂的La_(1-x)Sr_xCoO_3比LaCoO_3具有更高的电催化活性,并且La_(0.6)Sr_(0.4)CoO_3在氧还原和氧析出反应中均表现出最优的催化性能,最大电流密度分别达到0.244 A·cm~(-2)(-0.6 V vs Hg/HgO)和0.303 A·cm~(-2)(1 V vs Hg/HgO)。为进一步提高催化剂的催化活性,将水热法制备的α-MnO_2纳米管与La_(0.6)Sr_(0.4)CoO_3复合作为双功能催化剂。当α-MnO_2的质量分数为40%时,比起单一的α-MnO_2或钙钛矿氧化物,α-MnO_2/La_(0.6)Sr_(0.4)CoO_3复合材料表现出协同效应,有更好的双功能电催化活性,使双效氧电极具有更好的电化学性能及稳定性。     

氮掺杂还原氧化石墨烯/四氧化三钴双功能催化剂的制备及表征

采用尿素作为氮源,通过热退火法制备氮掺杂还原氧化石墨烯,然后以乙酰丙酮钴作为钴源通过水热法制备氮掺杂还原氧化石墨烯/四氧化三钴杂化纳米片作为催化氧还原和氧析出反应的双功能催化剂。利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线电子能谱仪(XPS)等对其进行形貌结构表征,通过旋转圆盘电极等电化学测试对其电催化性能进行分析,可以看出该催化剂具有良好的氧还原和氧析出催化性能。     

TiO2纳米管阵列光电催化氧化处理氨氮废水

用电化学阳极氧化法制备了高度有序的钛基二氧化钛纳米管阵列薄膜。用场发射扫描电镜(FE-SEM)、X射线衍射(XRD)表征样品的形貌与晶型特征。以二氧化钛纳米管阵列为光阳极,石墨为对电极,测试了不同pH值和外加偏压条件下的光电流响应和光电催化氧化降解NH4Cl水溶液(以N计,100 mg·L-1)的效率。结果表明:所制备的TiO2纳米管阵列具有锐钛矿和金红石的混晶结构,且主要晶型为锐钛矿。光电流响应的强弱与光电催化氧化效率的高低相对应,降解氨氮废水的最佳条件为pH=11,偏压为1.0 V。     

Strength and toughness of carbon fibers reinforced rigid polyurethane composites by adsorbing tannic acid and refining Ni grains on carbon fibers surface

In this article, short carbon fibers (CFs) reinforced rigid polyurethane (RPU) composites were prepared with the aim of improving both strength and toughness. A tannic acid (TA)‐nickel (Ni) composite coating was spontaneously co‐deposited onto CFs surface by a one‐step electrodeposition method to strengthen the interface bonding of the composites. The satisfactory mechanical properties of the composites were mainly attributed to the superior interfacial adhesion. On the one hand, TA could play a role in refining Ni grain during electrodeposition. On the other hand, the hydroxyl groups attached to composite coating, which were introduced by TA, could react with the RPU matrix to form chemical bonds. When the composites were under stress, the chemical bonds could effectively transfer the stress from matrix to the interface, while the refined Ni crystals could greatly increase the stress transfer path, and thus improve the strength and toughness of the material. Compared with pure RPU, the tensile strength, bending strength,interlaminar shear strength, and impact strength of TA‐Ni‐coated CFs/RPU composites were improved by 14.8%, 83.1%, 28.7%, and 121.4%, respectively.     

钡铁氧体包覆碳纤维的制备及毫米波衰减性能

通过溶胶凝胶法,在碳纤维表面均匀包覆了一层厚度约为1 μm的钡铁氧体(BaFe₁₂O₁₉)。采用SEM、FTIR、XRD、XPS等技术对碳纤维/钡铁氧体复合材料的组成、结构、性能进行了表征和分析。利用8 mm波雷达装置测试了碳纤维、碳纤维/钡铁氧体复合材料的毫米波衰减性能。实验结果表明：由于碳纤维/钡铁氧体复合材料兼具电损耗和磁损耗吸收,其8 mm波衰减性能明显优于单纯的碳纤维。     

Electrospinning preparation of NiO/ZnO composite nanofibers for photodegradation of binary mixture of rhodamine B and methylene blue in aqueous solution: Central composite optimization

One‐dimensional nanofiber of p‐type NiO/n‐type ZnO heterojunctions with various molar ratios of Ni to Zn at different calcination temperatures were successfully synthesized using the electrospinning method, and they were fully characterized. The photocatalysts thus obtained were applied in aqueous solutions for rhodamine B (RDB) and methylene blue (MB) degradation. The p–n heterojunctions built among the cubic structure NiO and hexagonal structure ZnO in the composite nanofiber are responsible for generation of electrons and holes and subsequently superoxide and hydroxyl radical production by carriers which lead to degradation of the dyes in solution. The composite nanofibers (ZnNi1) calcined at 550 °C for 3 h showed the highest photocatalytic activity for degradation of the dyes in aqueous solution. The optimum values were found to be 180 min, 7.0, 1 g l^?1 and 3.0 and 3.0 mg l^?1 for irradiation time, pH, photocatalyst dosage and initial concentration of RDB and MB, respectively. For these optimum conditions, the photocatalytic degradation of RDB and MB was found to be 99.37 and 98.44%, respectively. The maximum photodegradation of RDB and MB using ZnNi1 was 59.41 and 65.43%, respectively. First‐order kinetics based on the Langmuir–Hinshelwood model successfully fitted the experimental data.     

Cobalt-modified nickel–zinc catalyst for electrooxidation of methanol in alkaline medium

Cobalt-modified nickel-zinc catalyst CuNi(Zn)Co is prepared on a copper substrate by using electrodeposition. Its catalytic efficiency for methanol oxidation is studied with cyclic voltammetry, chronoamperometry, and chronopotentiometry techniques. The surface morphology and chemical composition of catalyst are characterized by scanning electron microscopy and energy dispersive X-ray spectroscopy. The oxidation kinetic parameters activation energy (Ea), active species on the surface (Γ), and rate constant (k) are determined from cyclic voltammograms which are performed at different methanol concentrations and temperatures. The results show that Ni(Zn)Co catalyst has higher catalytic activity than Ni, Co, and NiZn coatings as a composite catalyst for a promising choice of methanol electrooxidation in the alkaline medium.     

添加Al2O3对Ni0.5Zn0.5Fe2O4纳米纤维结构和磁性能的影响

采用静电纺丝技术制备了添加0～20wt%Al2O3的Ni0.5Zn0.5Fe2O4纳米纤维。通过XRD、FESEM、TEM和VSM对样品的物相结构、形貌和磁性能进行了表征。结果表明,所合成的复合纳米纤维的直径都分布在40～150 nm之间,添加到纤维中的Al2O3主要以非晶态形式分布于铁氧体晶粒边界;随着Al2O3添加量的增加,可观察到γ-Fe2O3相逐渐析出,Ni-Zn铁氧体的晶格常数单调减小,说明有一些Al2O3进入到尖晶石晶格中取代了B位的Fe3+离子,Ni-Zn铁氧体的平均晶粒尺寸先增大后减小,在Al2O3添加量为8wt%时达到最大值39.2 nm;比饱和磁化强度和矫顽力随Al2O3添加量的增加呈现出相同的变化规律,先减小后增大,当Al2O3添加量超过5wt%时又开始变小。     

电沉积Ni/LaNiO3复合电极及其在碱性介质中的析氧性能

采用溶胶-凝胶法制备了钙钛矿型复合氧化物LaNiO3,然后将其加入瓦特镀镍液中进行复合电沉积,研究了镀液pH值和阴极电流密度对Ni/LaNiO3复合镀层组成的影响。运用扫描电镜(SEM)、能谱分析(EDS)和X射线衍射(XRD)等对复合镀层进行表征,结果表明:最佳电沉积工艺条件是镀液pH=5.8和阴极电流密度jk=90 mA.cm-2,所得的Ni/LaNiO3复合镀层中LaNiO3的质量含量约为60%。用循环伏安、稳态极化、恒电位阶跃、电化学阻抗谱等电化学技术评价了Ni/LaNiO3复合电极的析氧性能。结果表明:在5 mol.L-1的KOH溶液中,Ni/LaNiO3复合电极的起始析氧电位较镍电极负,表观活化自由能比镍电极降低约2/3,比表面积约为镍电极的55倍,析氧电催化性能得到大幅度提高。     

MOF-derived hollow NiO–ZnO composite micropolyhedra and their application in catalytic thermal decomposition of ammonium perchlorate

Ni(II)-doped Zn-based coordination polymer particles (Ni(II)-doped Zn-CPPs) with controllable shape and size were successfully synthesized by solvothermal method, which further transformed to porous ZnO–NiO composite micropolyhedra without significant alterations in shape by calcination in air. Those products were characterized by powder X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), infrared spectroscopy (IR) and gas adsorption measurements. The catalytic activity of ZnO–NiO composites for the thermal decomposition of ammonium perchlorate (AP) was investigated. The result shows that all ZnO–NiO composites efficiently catalyzed the thermal decomposition of AP, and NiO–ZnO composite hollow octahedrons have the highest catalytic efficiency compared with that of most materials reported to now, indicating that porous ZnO–NiO composite micropolyhedra could be a promising candidate material for application in AP-based propellant.     

聚苯乙烯/银纳米粒子复合微球的合成及催化性能

首先通过乳液聚合和浓硫酸酸化制备表面富含磺酸根的磺化聚苯乙烯(PS)微球(直径532 nm),再用其静电吸附[Ag(NH_3)_2]~+离子,最后采用聚乙烯吡咯烷酮还原表面吸附的[Ag(NH_3)_2]~+离子,得到了负载银纳米粒子的PS/AgNPs复合微球.采用扫描电子显微镜、透射电子显微镜、紫外-可见光谱、红外光谱和X射线衍射表征了PS/AgNPs复合微球,并考察了其对甲基蓝(MB)的催化性能.结果表明,Ag纳米粒子高度分散在磺化PS微球表面;该PS/AgNPs复合微球对催化转化MB有较高的催化活性,并可多次重复利用.本研究在催化降解有机污染物方面有一定的实用价值.     

Methane reforming With CO2 to syngas over CeO2-promoted Ni/Al2O3-ZrO2 catalysts Prepared Via a direct sol-gel process

CeO2-promoted Ni/Al2O3-ZrO2 (Ni/Al2O3-ZrO2-CeO2) catalysts were prepared by a direct sol-gel process with citric acid as gelling agent. The catalysts used for the methane reforming with CO2 was studied by infrared spectroscopy (IR), thermal gravimetric analysis (TGA), microscopic analysis, X-ray diffraction (XRD) and temperature-programmed reduction (TPR). The catalytic performance for CO2 reforming of methane to synthesis gas was investigated in a continuous-flow micro-reactor under atmospheric pressure. TGA, IR, XRD and microscopic analysis show that the catalysts prepared by the direct sol-gel process consist of Ni particles with a nanostructure of around 5 nm and an amorphous-phase composite oxide support. There exists a chemical interaction between metallic Ni particles and supports, which makes metallic Ni well dispersed, highly active and stable. The addition of CeO2 effectively improves the dispersion and the stability of Ni particles of the prepared catalysts, and enhances the adsorption of CO2 on the surface of catalysts. The catalytic tests for methane reforming with CO2 to synthesis gas show that the Ni/Al2O3-ZrO2-CeO2 catalysts show excellent activity and stability compared with the Ni/Al2O3 catalyst. The excellent catalytic activity and stability of the Ni/Al2O3-ZrO2-CeO2 are attributed to the highly, uniformly and stably dispersed small metallic Ni particles, the high reducibility of the Ni oxides and the interaction between metallic Ni particles and the composite oxide supports.