Pt/纳米碳管空气电极氧还原反应的电催化性能

以不同质量比的铂、纳米碳管、活性炭为催化层制备空气电极并测定其稳态极化曲线和交流阻抗.研究发现,纳米碳管经硝酸处理后其氧还原反应性能得到提高,特别是将表面氧化后再沉积Pt,对氧的电还原反应影响更显著.以质量比4∶1的活性炭/纳米碳管载Pt制备的空气电极,在过电位ηc为500～600mV下,氧还原电流可达600～700mA·cm-2.EIS测试表明,纳米碳管载Pt后的欧姆极化阻抗和电化学阻抗均非常小.     

纳米碳管电极上氧的电催化还原

以聚四氟乙烯为粘结剂制成了多壁纳米碳管（MWNT）电极.采用恒电位阶跃法和循环伏安法研究了MWNT电极在碱性溶液中的电化学行为，并对碱性溶液中溶解氧在该电极上的电化学还原行为进行了研究.实验结果表明： MWNT电极具有比石墨电极更高的孔隙率和电化学表面积；MWNT电极上O2还原成的反应为准可逆过程；在5～50 mV•s－1的扫描速率范围内，阴极峰电流与扫描速度成线性关系，表明MWNT电极上O2还原成的反应受吸附控制；对碱性溶液中的氧还原反应， MWNT比石墨具有更高的催化活性.     

多壁纳米碳管空气电极的交流阻抗研究

研究了多壁纳米碳管、活性炭和石墨等空气电极的交流阻抗特性.结果表明,纳米碳管空气电极的阻抗谱由两个半圆组成,高频区半圆对应欧姆极化阻抗,低频区半圆对应电化学极化阻抗.催化剂Pt以纳米颗粒的形式沉积在碳管的外表面,明显减小了电极的欧姆阻抗和电化学极化阻抗,提高了氧还原反应的电催化活性.活性炭电极除存在电化学阻抗外,还存在薄液膜扩散阻抗(Nernst扩散),石墨电极形成的薄液膜反应区域较小,电极反应呈Warburg扩散阻抗特征,相应的电催化活性较低.采用交流阻抗等效电路分析方法,对拟合的动力学数据进行了解释.     

纳米碳管作为氧扩散电极催化层第二相碳载体的电极特性

A novel gas diffusion electrode using binary carbon supports (carbon nanotubes and active carbon) as the catalyst layer was prepared. The electrochemical properties for oxygen reduction reaction (ORR) in alkaline electrolyte were investigated by polarization curves and electrochemical impedance spectroscopy. The results show that the binary-support electrode exhibits higher electrocatalytic activity than the single-support electrode, and the best performance is obtained when the mass ratio of carbon nanotubes and activated carbon is 50 ∶50. The results from their electrode kinetic parameters indicate that the introduction of carbon nanotubes as a secondary support provides high accessible surface area, good electronic conductivity and fast ORR kinetics. The electrocatalytic activity of binary-support electrodes is obviously improved by the deposition of Pt nanoparticles on carbon nanotubes, even at very low Pt loading (45.7 μg/cm2). In addition, the EIS analysis results show that the process of ORR may be controlled by diffusion of oxygen in the thin film for binary-support electrodes with or without Pt catalyst.     

聚血红素修饰电极上氧还原的电催化研究

 采用循环伏安法和电位阶跃法,研究了水溶液中溶解氧在聚血红素修饰电极上还原反应的电催化作用．结果表明,还原峰电流随扫描速度的增大而增强,Ip～v1／2呈线性关系．根据电位阶跃实验的I～t曲线,计算出电极反应的电子转移数约为2,推断其催化机理属于ECE催化过程．     

碳化钨电极上氧的电催化还原

以喷雾干燥微球化处理的偏钨酸铵作为前驱体,CO/H2为碳化还原气源,应用固定床气固反应法制备碳化钨(WC)粉体,再以聚四氟乙烯作粘结剂制成碳化钨电极.应用XRD和SEM等表征、观察碳化钨样品,循环伏安和线性扫描法研究硫酸电解液中WC电极的氧还原电催化行为.检测表明,WC为球状颗粒;WC电极对氧还原反应具有较好的电催化活性,硫酸溶液中溶解氧还原反应控制步骤为吸附态(O2-)ads的生成;增加硫酸电解液浓度,开路电位正移,升高温度有利于反应进行.     

Co-WC复合电极在碱性介质中的电催化析氢性能

Co-WC复合电极在碱性介质中的电催化析氢性能     

La_(1-x)Sr_xCoO_3气体扩散电极在碱性条件下的氧还原电催化性能

用涂覆加压成型方法制备了具有钙钛矿结构的 La1 - x Srx Co O3多孔气体扩散电极 ,测定了它们的稳态阴极极化曲线和循环伏安图谱。通过对多孔铂电极与 La1 - x Srx Co O3多孔气体扩散电极的相关曲线的对照分析 ,得出了L a1 - x Srx Co O3在碱性条件下 ,具有比铂更好的氧还原催化活性的结论。并计算出 L a1 - x Srx Co O3多孔电极的表观交换电流密度 i0 =7.6 8× 1 0 - 4 A/cm2 ,比同样条件下的铂电极的 i0 高 3～ 4个数量级。     

用于电催化析氧反应电极的制备策略

随着能源枯竭和环境污染等问题的日益严重,开发清洁可再生能源及相关新型技术迫在眉睫。近年来,水分解、金属-空气电池等电化学能源储存和转换技术得到人们的广泛关注。电催化析氧反应(Oxygen evolution reaction,OER)是其中的一个关键反应,大量高性能的OER电催化剂不断见诸报道。除了材料本征催化活性的影响,不同的电极制备方式同样会对催化剂性能的发挥起到重要作用,越来越多的研究者致力于探索高效OER电极的设计与制备方法。本综述从方法论的角度,详细介绍了目前高效OER电极的制备策略,讨论了各类制备方式的优势和不足,总结了相关工作的最新研究进展,概述了新型电极的制备方法。最后,对电极制备策略的发展方向进行了总结与展望。     

钯纳米粒子在电极表面的制备及其对氧的催化还原

纳米微粒的体积效应使其成为表面纳米工程及功能化纳米结构材料制备的理想研究对象 [1～ 3] .纳米粒子具有独特的电子、催化及光学特性[4 ] ,近年来关于纳米粒子的制备及其在材料科学领域中的应用受到研究者的极大关注 .而贵金属纳米粒子由于其在催化领域中的广泛应用而成为最重要的研究对象之一[5,6 ] .电催化氧还原是一直为化学家瞩目的研究领域[7～ 9] .研究主要目的之一是寻找合适的氧电极反应催化剂 ,并使之能够应用于燃料电池中 .其中催化氧电极材料研究得最多的是贵金属 Pt[10 ,11] .贵金属 Pd对氧催化还原的研究工作很少 .我们首次…     

通过铁掺杂和造孔提高氮掺杂石墨烯/碳纳米管复合物电催化氧还原性能的研究（英文）

氧还原反应催化剂的性能直接影响着能源转换和存储器件如燃料电池和金属-空气电池的性能. 开发低成本、高性能的非铂族金属氧还原催化剂对于这类器件的实际应用和商业化十分重要,因此备受关注. 氮掺杂的石墨烯/碳纳米管复合物同时具备碳纳米管的良好导电性能和有利于传质的三维网络结构优点,以及氮掺杂石墨烯的高活性优点,因此有望发展为这类可替代铂族催化剂的氧还原电催化剂之一,但目前其催化性能还需进一步提高. 本文研究发现通过在氮掺杂石墨烯/碳纳米管复合物的过程中引入铁元素可以有效提高催化剂的氧还原活性,并且发现通过在热处理和氮掺杂过程中加入二氧化硅纳米颗粒及随后除去二氧化硅,可以在氮掺杂的石墨烯/碳纳米管复合物材料中有效地形成多孔结构. 这种多孔结构的形成不仅可以在复合物中引入更多的高活性催化位点,而且有利于暴露更多的催化活性位并促进氧还原反应中的传质过程. 结合碳纳米管、石墨烯和多孔结构的三者优点,所制备的多孔氮掺杂碳材料表现出优异的电催化氧还原性能. 进一步的实验表明,这类材料还表现出优异的抗甲醇中毒能力和良好的稳定性,因此在性能改进后有望用于燃料电池等能量转换与存储器件.     

Fully Oriented Bilirubin Oxidase on Porphyrin‐Functionalized Carbon Nanotube Electrodes for Electrocatalytic Oxygen Reduction

The efficient immobilization and orientation of bilirubin oxidase from Myrothecium verrucaria on multi‐walled carbon nanotube electrodes by using π‐stacked porphyrins as a direct electron‐transfer promoter is reported. By comparing the use of different types of porphyrin, the rational effect of the porphyrin structure on both the immobilization and orientation of the enzyme is demonstrated. The best performances were obtained for protoporphyrin IX, which is the natural precursor of bilirubin. These electrodes exhibit full orientation of the enzyme, as confirmed by the observable non‐catalytic redox system corresponding to the T1 copper center associated with pure Nernstian electrocatalytic behavior with high catalytic currents of almost 5 mA cm^?2 at neutral pH.     

Electrocatalytic Reduction of Nitrite Using a Carbon Nanotube Electrode in the Presence of Cupric Ions

A simple, inexpensive method for determining nitrite is presented. With a carbon nanotube modified glass carbon electrode (GC), the overpotential for reduction of nitrite decreased, and direct reduction could be achieved in acid solution. Sensitivity, however, was not very high. When cupric ions were added to the solution, the reduction peak current increased significantly, and in particular the presence of multiple nitrate did not interfere. Experimental conditions were optimized, and preliminary studies were performed on the electrochemical mechanism of nitrite reduction in the presence of cupric ions on the carbon nanotube modified electrode. Under optimized conditions, the peak current of reduction achieved with the differential pulse voltammetric method was proportional to the concentration of nitrite in the ranges of 2.0×10^–6–1.0×thinsp;10^–5molL^–1 and 2.0×10^–5–1.0×10^–3molL^–1. The detection limit reached 5.0×10^–7molL^–1, and most of the inorganic ions did not interfere. The determination of nitrite in samples of rain water and river water was satisfactory.     

多巴胺为前驱体过渡金属与N共同掺杂的碳纳米管催化剂ORR性能研究

采用多巴胺的自氧化聚合在多壁碳纳米管表面进行聚合沉积修饰,经热处理可得到氮掺杂的碳纳米管催化剂,通过调整沉积次数可控制表面聚多巴胺C-N膜的厚度,从而调控N的掺杂量.研究沉积次数对多壁碳纳米管催化剂表面形貌、化学组成及原子结合形态的影响,并考察N掺杂的多壁碳纳米管催化剂的氧还原反应活性.在此基础上,用多巴胺配合Mn、Fe离子进行共同聚合沉积,热处理后得到Mn(Fe)、N共同掺杂的多壁碳纳米管催化剂,对催化剂进行了多种测试和电化学表征.循环伏安和线性扫描的电化学表征表明,N掺杂可有效提高催化剂的氧还原反应(ORR)活性,C-N膜的厚度会影响催化剂性能,Mn(Fe)-N@MWCNTs催化剂的氧还原活性高于只有N掺杂的催化剂,两种催化剂氧还原反应均为4电子反应路径,可直接将氧气还原成H_2O,且F e-N@MWCNTs催化剂表现出较好的抗甲醇能力.SEM照片可以看到聚多巴胺在碳纳米管表面形成C-N膜;R aman分析表明聚多巴胺沉积后提高了催化剂表面的无序性,缺陷增多;XPS表征显示过渡金属的掺杂改变了CN_x的结合状态.     

Electrocatalytic Reduction of Oxygen at Multi‐Walled Carbon Nanotubes and Cobalt Porphyrin Modified Glassy Carbon Electrode

The multi‐walled carbon nanotubes (MWNTs) modified glassy carbon electrode exhibited electrocatalytic activity to the reduction of oxygen in 0.1 M HAc‐NaAc (pH 3.8) buffer solution. Further modification with cobalt porphyrin film on the MWNTs by adsorption, the resulted modified electrode showed more efficient catalytic activity to O₂ reduction. The reduction peak potential of O₂ is shifted much more positively to 0.12 V (vs. Ag/AgCl), and the peak current is increased greatly. Cyclic voltammetry (CV), transmission electron microscopy (TEM), X‐ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM), were used to characterize the material and the modified film on electrode surface. Electrochemical experiments gave the total number of electron transfer for oxygen reduction as about 3, which indicated a co‐exist process of 2 electrons and 4 electrons for reduction of oxygen at this modified electrode. Meanwhile, the catalytic activities of the multilayer film (MWNTs/CoTMPyP)_n prepared by layer‐by‐layer method were investigated, and the results showed that the peak current of O₂ reduction increased and the peak potential shifted to a positive direction with the increase of layer numbers.     

Observing Single Hollow Porous Carbon Catalyst Collisions for Oxygen Reduction at Gold Nanoband Electrode

The evaluation of single carbon particle catalysts is critical to better understand the relationship between structure and properties. Here, we use an electrochemical collision method to study the electrocatalytic behaviour of single hollow porous carbon catalyst on gold nanoband electrodes (AuNBE). We observed the catalytic current of oxygen reduction of single carbon particle and quantified the contribution of the porous structure to the catalytic performance. We find that the meso/microporous and hollow structures contribute to the electrocatalytic current. Our research provides direct evidence that the hollow/porous structures improve the electrocatalytic performance.