Carbon Nanotubes Supported Pt-Ru-Ni as Methanol Electro-Oxidation Catalyst for Direct Methanol Fuel Cells

Carbon nanotubes (CNTs) supported Pt-Ru and Pt-Ru-Ni catalysts were prepared by chemical reduction of metal precursors with sodium borohydride at room temperature. The crystallographic properties and composition of the catalysts were characterized by X-ray diffraction (XRD) and energy dispersive X-ray (EDX) analysis, and the catalytic activity and stability for methanol electro-oxidation were measured by electrochemical impedance spectroscopy (EIS), linear sweep voltammetries (LSV), and chronoamperometry (CA). The results show that the catalysts exhibit face-centered cubic (fcc) structure. The particle size of Pt-Ru-Ni/CNTs catalyst is about 4.8 nm. The catalytic activity and stability of the Pt-Ru-Ni/CNTs catalyst are higher than those of Pt-Ru/CNTs catalyst.     

Preparation of High-alloying Pt-Ru/CMK-3 Catalysts in THF-H2O-EtOH Ternary Solution System

The Pt-Ru particles of the Pt-Ru/CMK-3 catalyst were found to possess high degree of alloying, small average size, and low relative crystallinity when the Pt-Ru/CMK-3 catalyst was prepared using the general chemical reduction method in the ternary solution system containing tetrahydrofuran (THF), H₂O, and ethanol. The Pt-Ru/CMK-3 catalyst showed high electrocatalytic activity for methanol oxidation. It indicated that the alloying of Pt-Ru could significantly affect the electrocatalytic activity for methanol oxidation. The Pt-Ru/CMK-3 catalyst with high alloying degree can be obtained because THF and H₂PtCl₆ can form a complex leading to the reduction potentials of H₂PtCl₆ and RuCl₃, which are close to each other in the aqueous solution with THF.     

Nd_x作为助催化剂对PtRu/C电催化氧化甲醇活性的影响

采用沉积-还原法制备了PtRu-NdOx/C催化剂,借助TEM、EDS和XRD等测试手段对其进行了微结构和组成的表征.结果表明,催化剂中Pt与Ru以合金形式存在,而Nd的氧化物则以无定形形态存在.催化剂粒子的平均粒径在2nm左右,晶胞参数为0.3896nm,Nd氧化物的加入对PtRu合金的晶体结构影响不明显.采用循环伏安法和计时电流法,比较了PtRu-NdOx/C催化剂和PtRu/C催化剂对甲醇氧化的电催化活性,结果表明,加入Nd的氧化物作为助催化剂能明显提高PtRu/C催化剂对甲醇氧化的电催化性能.     

NdOx作为助催化剂对PtRu/C电催化氧化甲醇活性的影响

采用沉积-还原法制备了PtRu-NdOx/C催化剂, 借助TEM、EDS和XRD等测试手段对其进行了微结构和组成的表征. 结果表明, 催化剂中Pt与Ru以合金形式存在, 而Nd的氧化物则以无定形形态存在. 催化剂粒子的平均粒径在2 nm左右, 晶胞参数为0.3896 nm, Nd氧化物的加入对PtRu合金的晶体结构影响不明显. 采用循环伏安法和计时电流法, 比较了PtRu-NdOx/C催化剂和PtRu /C催化剂对甲醇氧化的电催化活性, 结果表明, 加入Nd的氧化物作为助催化剂能明显提高PtRu /C催化剂对甲醇氧化的电催化性能.     

一种制备碳载高合金化Pt-Ru催化剂的方法

提出了在四氢呋喃(THF)和H₂O混合溶液中用一般的化学还原法在室温下制备碳载Pt-Ru(Pt-Ru/C)催化剂的新方法。与在纯水中制得的Pt-Ru/C催化剂相比，其Pt-Ru粒子的合金化程度高、平均粒径较小且相对结晶度低，因此，该催化剂对甲醇氧化的电催化活性远高于在纯水中制得的Pt-Ru/C催化剂。高合金化程度的原因是H₂PtCl₆和RuCl₃在THF和H₂O混合溶液中的起始还原电位相近。此外，在THF和H₂O混合溶液中，THF和H₂O的体积比的改变并不影响制得的Pt-Ru/C催化剂中Pt-Ru粒子的合金化程度，但对Pt-Ru粒子的粒径以及相对结晶度有较大影响。     

四氢呋喃-水-乙醇三元溶液体系制备高合金化Pt-Ru/CMK-3催化剂

提出了在四氢呋喃(THF)、H2O和乙醇三元体系中用一般的化学还原法在室温下制备高合金化Pt-Ru/CMK-3催化剂的新方法. 与在纯水中制得的商品化ETEK催化剂相比, 其Pt-Ru粒子的合金化程度高、平均粒径较小且相对结晶度低, 因此, 该催化剂对甲醇氧化的电催化活性远高于在纯水中制得的Pt-Ru催化剂. 高合金化程度的原因是H2PtCl6和RuCl3在THF、H2O和乙醇三元溶液体系中的起始还原电位相近. 此外, CMK-3以其规整的二维有序孔道结构, 为直接甲醇燃烧电池(DMFC)中电子和物质的传输提供了方便的路径, 其巨大的比表面积也为Pt-Ru 纳米粒子的均匀分散提供了良好的载体.     

合金化程度对炭载Pt-Ru催化剂性能的影响

在含四氢呋喃(THF)的水溶液中, 室温下用NaBH₄还原H₂PtCl₆和RuCl₃制得Pt-Ru/C催化剂. 其Pt-Ru 粒子的合金化程度较高, 平均粒径较小, 相对结晶度较低. 因此对甲醇氧化的电催化活性远高于Pt-Ru 粒子的平均粒径和相对结晶度相似的, 而且Pt-Ru合金化程度低的商业化的E-TEK的Pt-Ru/C催化剂, 表明Pt-Ru的合金化程度对Pt-Ru/C催化甲醇氧化的电催化活性有很大的影响.     

高分散PtRu/C催化剂的制备及对甲醇及吸附态CO的电催化氧化

采用化学还原浸渍法在两种不同条件下制备炭载PtRu催化剂,通过XRD和TEM技术对催化剂的晶体结构及微观形貌进行了分析,运用循环伏安法、线性扫描法来检测不同条件下制备的催化剂对甲醇及吸附态CO(COad)电催化氧化活性的影响.结果表明,不同条件下制备的催化剂Pt和Ru形成合金的程度不同,Pt-Ru合金原子的颗粒在载体炭上的粒径大小和分布不同,导致催化剂对甲醇及COad的电氧化催化活性不同.其中以甲醛为还原剂在乙二醇体系中制备的催化剂PtRu/C-2能形成较好的合金状态,粒径小,分布均匀,对甲醇及COad的氧化具有较高的电催化活性.     

NiO增强Pt/C催化剂催化氧化甲醇活性的研究

本文基于NiO作为Pt催化甲醇助催化剂的思路,通过Pt纳米颗粒担载在NiO修饰的碳材料载体上制备了Pt/NiO-C催化剂,系统地研究了不同的NiO/C热处理温度对Pt粒径的影响,并重点探讨了Pt对NiO的质量比对催化氧化甲醇的影响。X射线衍射分析结果显示NiO和Pt均为立方晶系,且NiO的加入有利于主催化剂Pt形成较小的粒径,且经400℃热处理NiO修饰的C材料作为载体有利于Pt的有效分散。所获得的Pt/NiO-C催化剂的电化学活性在甲醇酸性溶液中通过循环伏安法(CV)和计时电流法(CA)进行性能测试。CV测试结果显示以Pt/NiO重量比为4∶1的催化剂其电氧化甲醇活性最大,其峰值氧化电流密度达806 mA/mgPt,是Pt/C催化剂的1.64倍。CA测试结果显示Pt/NiO-C比Pt/C具有更好的抗CO中毒性能和稳定性。     

室温制备高合金化Pt-Ru/CMK-3催化剂及其对甲醇的电催化氧化

通过低温络合反应制备了高分散高合金化的Pt-Ru固溶体, 并将其均匀地担载在有序介孔碳CMK-3上, 以形成二元复合金属催化剂. XRD谱图表明,fcc结构的Pt原子部分被hcp结构的Ru原子取代形成置换固溶体， 而且几乎没有未形成合金的Ru存在. TEM和XRD研究结果表明， Pt-Ru/CMK-3催化剂中Pt-Ru合金粒子的平均粒径为27 nm, 且具有良好的均一度. 还研究了催化剂对甲醇的电催化氧化性能, 并与E-TEK公司同类催化剂进行了对比, 研究结果表明, Pt-Ru/CMK-3催化剂具有较大的电化学活性面积, 对甲醇的电催化氧化性能和抗CO中毒能力明显优于其它同类催化剂.     

PdNiO/C在碱性介质中对甲醇的电氧化

应用循环伏安,计时电流,计时电位和XRD等方法研究了碱性介质中甲醇在自制PdNiO/C和Pd/C催化剂上的电化学氧化以及高温热处理对催化剂结构和性能的影响.结果表明,还原温度为70℃,Pd、Ni原子比为8∶2时,PdNiO/C催化剂对甲醇电化学氧化具有较好的催化活性.热处理可增大催化剂粒径,升高结晶度,降低分散度和催化活性,并且可使NiO从Pd的晶格中脱离出来.与Pd/C催化剂相比,优选的PdNiO/C催化剂有更高的催化活性和更好的抗毒化能力.     

Investigation of Pt–Ru nanoparticle catalysts for low temperature methanol electro-oxidation

Pt–Ru nanoparticle-based methanol electro-oxidation catalysts with high concentration of metallic phase on carbon black have been synthesised by a low-temperature colloidal preparation route. Amorphous Pt–Ru oxide nanoparticles were deposited on carbon and subsequently reduced in hydrogen stream at different temperatures to obtain crystalline phases with tailored particle size. The electro-catalytic activity for methanol oxidation was investigated in half-cell from 30 to 60 °C. The results were interpreted in terms of particle size, crystallographic structure, degree of alloying and carbon monoxide adsorption properties. The best performance was achieved for the catalyst with intermediate particle size in the investigated range. Furthermore, it is observed that the optimal properties for these catalysts depend on the operating temperature.     

新型阳极材料Pt-Ru/CMK-3的制备与性能研究

通过在多元金属体系中加入络合剂四氢呋喃(THF), 改变其热力学参数进而改变其动力学还原速率, 在低温下同时还原金属Pt和Ru, 制备了高分散、高合金化的Pt-Ru固溶体并均匀担载在有序介孔碳CMK-3上, 以形成二元复合金属催化剂. XRD图谱表明, f.c.c结构中Pt原子部分被h.c.p结构中Ru原子取代形成置换固溶体, 且几乎没有未合金的Ru存在. TEM, XRD和N₂吸附-脱附研究显示, Pt-Ru/CMK-3催化剂中Pt-Ru合金粒子的平均粒径为3.2 nm, 且具有良好的均一度. 还研究了催化剂对甲醇的电催化氧化性能, 并与E-TEK公司同类催化剂进行了对比. 结果显示, Pt-Ru/CMK-3催化剂拥有较大的电化学活性面积, 对甲醇的电催化氧化性能和抗CO中毒能力明显优于其他同类催化剂.     

Pt-SnO2 / C催化剂对乙醇和吸附态CO的电催化氧化

由于乙醇最有可能成为直接甲醇燃料电池（DMFC）的替代燃料，因此近年来。对乙醇的电化学氧化及直接乙醇燃料电池的研究已引起人们的很大兴趣。甲醇毒性较大并且易透过Nafion膜进入阴极造成阴极的混合电位而影响DMFC的阴极性能．这是制约DMFC走向实用化的主要问题之一。因此人们在致力于研究直接甲醇燃料电池的同时．也寻求其它的小分子醇作为甲醇的替代燃料。乙醇是除甲醇以外最简单的醇．它来源广泛．无毒，是可再生和环保型能源．并且也有较高的能量密度和反应活性。但是乙醇在电极上的完全氧化因涉及到C-C键的断裂要比甲醇困难．阳极反应动力学过程也比较缓慢。到目前为止铂基催化剂仍然是乙醇氧化最好的催化剂．虽然也有使用非铂催化剂研究乙醇的电氧化，但催化活性远不如铂基催化剂高。     

炭载Pt-Ag双金属催化剂对甲醇氧化反应的电催化

以NaBH4为还原剂,将K2PtCl6和AgNO3前体进行共还原制备了一系列具有不同组成的碳载PtmAg/C合金催化剂（m为Pt/Ag原子比,m为0.05～1.0）,在酸性介质中考察了该系列催化剂对甲醇氧化反应的电催化性能。 与单组分Pt/C催化剂相比,系列PtmAg/C催化剂呈现出较高的催化氧化甲醇的活性与抗CO毒化能力,而且该催化剂的性能与其组成密切相关。 随m值增加,PtmAg/C催化剂对甲醇氧化反应的质量比催化活性(MSA)、本征催化活性(IA)与稳定性均逐步增加,当m=0.5时催化活性达到最高,其MSA和IA分别是Pt/C催化剂的5.1和4.8倍。     

碱性介质中W,Ni和Sn掺杂的Pt-Ru/C电催化氧化甲醇的性能

直接以Pt, Ru, W, Ni和Sn的金属盐为前驱体, 通过溶胶法制备了不同原子比的Pt-Ru-M/C(M=W, Ni, Sn)碳载纳米合金催化剂, 用X射线衍射(XRD)和X光电子能谱(XPS)表征催化剂的晶相结构、表面组成及价态形式, 采用循环伏安法测试催化剂电催化氧化甲醇活性. 结果表明, 掺杂Ni和W可明显提高Pt-Ru/C催化活性, 掺杂Sn则降低了Pt-Ru/C催化活性. 其中Pt5-Ru4-Ni0.7/C的活性最高, 在1.0 mol/L NaOH＋1.0 mol/L CH3OH溶液中峰电流达835.2 mA/mg, 甲醇起始氧化电位比Pt5-Ru5/C低约0.11 V.     

铂、钌共修饰碳纳米管电极的制备及对甲醇的电催化氧化

碳纳米管以其独特的结构,良好的电性能和机械性能吸引了众多的关注~([1]),被认为是潜在的异相催化剂载体 ~([2]).近来关于碳纳米管负载催化剂的合成及其在异相催化中应用的研究已见报道~([3]).     

Pattern recognition on the structure-activity relationship of nano Pt-Ru catalysts: methodology and preliminary demonstration

The activity of nano Pt-Ru catalysts is a multivariate function of particle size, alloyed degree, oxide composition, and so forth. The monodependencies of catalytic activity on individual structure parameters (structure-activity relationship, SAR) are of great importance but, unfortunately, unobtainable in practical measurements. A pattern-recognition methodology is proposed for the first time to extract SAR information from all of the relative experimental data, which we hope will cast new light on the in-depth understanding of this important catalyst. As a preliminary demonstration, a multivariate linear regression and a generalized regression neural network were applied to analyze a small data set for methanol oxidation. It was found that both increasing the content of hydrous ruthenium oxides and decreasing the particle size would benefit the catalytic activity, whereas the effect of the Pt-Ru alloy degree turned out to be unremarkable.     

Pt-Ru supported on double-walled carbon nanotubes as high-performance anode catalysts for direct methanol fuel cells

Pt-Ru supported on carbon nanotubes (CNTs) (single-walled nanotubes, double-walled nanotubes (DWNTs), and multi-walled nanotubes) catalysts are prepared by an ethylene glycol reduction method. Pt-Ru nanoparticles with a diameter of 2-3 nm and narrow particle size distributions are uniformly deposited onto the CNTs. A simple and fast filtration method followed by a hot-press film transfer is employed to prepare the anode catalyst layer on a Nafion membrane. The Pt-Ru/DWNTs catalyst shows the highest specific activity for methanol oxidation reaction in rotating disk electrode experiments and the highest performance as an anode catalyst in direct methanol fuel cell (DMFC) single cell tests. The DMFC single cell with Pt-Ru/DWNTs (50 wt %, 0.34 mg Pt-Ru/cm(2)) produces a 68% enhancement of power density, and at the same time, an 83% reduction of Pt-Ru electrode loading when compared to Pt-Ru/C (40 wt %, 2.0 mg Pt-Ru/cm(2)).     

Metal Oxide Promoted Electrocatalysts for Methanol Oxidation

An important research target in DMFCs is to find better catalyst materials that are cheaper, less-prone to poisoning and more catalytically active. In this context, metal oxides with good catalytic properties and stronger interaction with Pt nanoparticles can generate active interfacial regions for electrocatalysis. Pt catalysts promoted by certain metal oxides show enhanced methanol electro-oxidation activity and CO tolerance behavior. In this paper we summarize the recent progress from our laboratory which explored the possibility of developing Pt–MoO₃/C and Pt–Nb₂O₅/C electrocatalysts in acidic media, and Pt–V₂O₅/C electrocatalyst in alkaline media for direct electro-oxidation of methanol. The oxide electrocatalysts have been prepared by a fast and efficient method of loading the metal oxide on carbon black (Vulcan XC-72) employing an intermittent microwave heating (IMH) method. These materials are found to achieve higher activity and stability towards methanol electro-oxidation.