PtMo合金催化剂氧还原反应催化性能研究

采用乙二醇还原法和后续的热处理工艺制备了Pt-Mo合金催化剂。使用透射电子显微镜、X射线衍射、电感耦合等离子体发射光谱、X射线光电子能谱等方法对样品进行了形貌、结构和组分的表征。通过电化学测试方法,探究了不同催化剂的电催化活性和稳定性。结果表明：合适的热处理温度不仅提高了Pt-Mo纳米颗粒的合金化程度,而且改变了催化剂颗粒表面的电子结构和成分。所以,经过400℃热处理的PtMo/C-400催化剂表现出较好的氧还原性能,其电催化活性和稳定性均与商业J01-Pt/C催化剂相当。     

PEMFC Pt-WO3/C电催化剂的制备与性能表征

以VulcanXC-72碳作为催化荆载体,采用分步化学沉积方法制备了碳黑担载的Pt-WO3电催化剂.通过XRD、循环伏安等物理和电化学手段对催化剂样品进行了测试和表征,结果表明该催化剂具有更高的氧还原起始电位和峰值电位,表现出良好的电催化氧还原性能,可作为质子交换膜燃料电池阴极氧还原的电催化剂.     

用于氧还原反应的PtNi合金催化剂研究进展

氧还原反应是质子交换膜燃料电池阴极催化反应的关键步骤。氧还原活性趋势图(火山图)中,贵金属Pt超高的催化性能显而易见,因此目前氧还原性能最佳的商业化催化剂仍然是碳载铂(Pt/C)。另一方面,Pt昂贵的价格也促使国内外研究者尝试开发Pt合金催化剂、非Pt催化剂等新型催化剂。在开发低Pt催化剂过程中,通过添加过渡金属来改变d带中心是较普遍的解决方案。研究者发现PtNi/C催化剂的氧还原性能远超商业化Pt/C催化剂,但催化剂中的过渡金属Ni在酸性条件下易溶解,从而破坏反应环境,导致稳定性较差。当前针对该问题的研究主要聚焦于调节催化剂晶面、表面应变以及组成结构,通过改变这些因素试图提高催化剂的电化学活性和耐久性。其中,由Pt₃Ni(111)面封闭形成的八面体纳米颗粒已经被认为是很有前途的氧还原反应电催化剂,成为了PtNi双金属催化剂中的研究热点。此外,对合金表面进行其他金属/非金属元素修饰,改善催化剂载体性质,也可以实现催化剂氧还原性能的提高。本文综述了近些年用于氧还原反应的Pt-Ni基催化剂的研究现状,主要包括通过催化剂形貌调控来控制暴露晶面、对催化剂进行表面修饰,以及...     

热处理对FeN/C催化剂氧还原性能的影响

高活性、低沉本的阴极氧还原催化剂是目前质子交换膜燃料电池的重要研究内容之一。考察了FeN/C作为氧还原催化剂的催化性能,研究氨气气氛下的二次热处理对催化剂氧还原催化活性与稳定性的影响。使用X射线衍射、比表面积和孔径分布测试、透射电子显微镜等方法对催化剂的结构进行表征,使用线性扫描伏安法对催化剂的氧还原活性进行测试。结果表明,经二次热处理后,催化剂表现出更好的氧还原催化活性及稳定性。催化剂在二次热处理后,具有更高的比表面积(931.2 m~2/g)、较高的表面氮含量(1.67%(原子分数))、以及催化剂中存在的Fe_3C,是其催化性能提高的可能原因。     

Pt-Ir合金化提高PEMFC中纯铂催化剂的催化活性和稳定性

采用乙二醇为还原剂的液相还原法和后续热处理途径制备了Pt/Ir原子比1∶1的Pt-Ir合金催化剂,利用X射线衍射(XRD)、透射电子显微镜(TEM)、电感耦合等离子体质谱(ICP)、X射线光电子能谱(XPS)等方法对合金催化剂的形貌和结构进行了表征,并采用循环伏安法(CV)、线性电势扫描(LSV)等电化学方法评价了它们的电催化活性和稳定性。结果表明,经过400℃热处理的Pt-Ir/CNC-400催化剂表现出了高于商业JM催化剂的电催化性能和稳定性。其原因主要在于,Pt-Ir纳米颗粒的合金化作用使颗粒表面的电子结构和组成发生了变化,更有利于提高催化剂的催化活性。     

阴极氧还原催化剂Co基过渡金属硫族化合物的研究进展

简要介绍了高压合成法、固态反应法、水热/溶剂热法、机械合金化法、磁电溅射法、低温回流法等几种制备Co基过渡金属硫族化合物的方法,综述了质子交换膜燃料电池(PEMFC)阴极Co基过渡金属硫族化合物催化剂的研究进展,重点讨论了Co-Se、Co-S、Co-Te等催化剂对氧还原反应(ORR)的催化活性,提出了阴极Co基过渡金属硫族化合物催化剂存在的问题以及发展趋势.     

质子交换膜燃料电池阴极铂合金催化剂研究进展

氧电极还原电催化剂对于质子交换膜燃料电池的发展具有重要的意义.综述了阴极铂合金催化剂的研究现状,包括催化剂的制备方法、影响催化剂性能的主要因素、合金催化剂性能提高的机理分析等.     

Co-MOF衍生Co-N-C催化剂的制备及其氧还原性能研究

金属-氮-碳(M-N-C)化合物作为非贵金属催化剂具有优异的氧还原(ORR)性能,在燃料电池和金属-空气电池等电化学能源转化方面展现了广阔的应用前景.开发出能够与贵金属铂催化剂相媲美的高效且廉价的催化剂以解决ORR缓慢动力学问题具有重要意义.选用金属有机骨架材料ZIF-67作为碳源和氮源,其中,二价钴离子、2-甲基咪唑...     

酸处理对FeN/ZIF-8催化剂氧还原反应催化性能的影响

研发高性能、低成本的非贵金属阴极氧还原反应催化剂是目前质子交换膜燃料电池的主要研究方向之一。以1, 10-菲啰啉为氮源, FeSO₄·7H₂O为铁源, 考察以ZIF-8为载体制备的FeN/ZIF-8催化剂的氧还原反应催化性能, 并探究酸处理对FeN/ZIF-8催化剂结构及性能的影响。通过X射线衍射、比表面积和孔径分布测试、透射电子显微镜等物理表征手段对催化材料进行结构表征, 使用旋转圆盘电极对催化剂氧还原反应催化活性和稳定性进行测试。结果表明: 以ZIF-8为载体制备的催化剂含有Fe₃C, 以及具有较大的比表面积, 这可能是催化剂具有较高氧还原反应初始催化活性的原因。酸处理可去除催化剂中部分不稳定的含铁碳化物和无序碳结构, 使催化剂具有更大的比表面积、更丰富的介孔结构和更高的孔体积; 同时, 酸处理可提高碳基体的耐腐蚀性, 在老化测试中维持催化剂所具有的较高比表面积和丰富的介孔结构, 从而使FeN/ZIF-8-A催化剂表现出更好的氧还原反应活性和稳定性。     

用于质子交换膜燃料电池的高活性、高稳定性PtIrFe/C三元合金催化剂

采用催化裂解法制备了多孔碳,将其作为催化剂载体,利用液相还原和真空热处理工艺制备出PtIrFe/C三元合金催化剂。采用X射线衍射、透射电子显微镜等手段对样品的结构形貌进行表征。使用电化学测试手段研究了不同热处理温度对其催化性能的影响。实验结果表明,热处理带来的合金化作用使催化剂的催化活性和耐久性得到了极大的提高。经过700℃热处理的样品,其面积比活性和质量比活性分别是传统商业Pt/C催化剂的3~4倍。     

A simple synthesis method for nanostructured Co-WC/carbon composites with enhanced oxygen reduction reaction activity

Co nanoparticles (Co NPs) and nanoscale tungsten carbide (WC) are successfully synthesized simultaneously with mesoporous structured carbon black (C) using an innovative simple method, which is known as solution plasma processing (SPP), and NPs are also loaded onto carbon black at the same time by SPP. The introduction of Co NPs led to not only superior oxygen reduction reaction (ORR) activity in terms of onset potential and peak potential, but also to a more efficient electron transfer process compared to that of pure WC. Co-WC/C also showed durability for long-term operation better than that of commercial Pt/C. These results clearly demonstrate that the presence of Co NPs significantly enhanced the ORR and charge transfer number of neighboring WC NPs in ORR activities. In addition, it was proved that SPP is a simple method (from synthesis of NPs and carbon black to loading on carbon black) for the large-scale synthesis of NP-carbon composite. Therefore, SPP holds great potential as a candidate for next-generation synthetic methods for the production of NP-carbon composites.     

金属-氧气电池中调控超氧化物稳定性实现大幅增强的固体催化剂氧还原反应活性

单电子或双电子氧还原反应(ORR)是非质子型金属-氧气电池的关键过程,其中超氧化物中间体或产物(O_(2)^(-),LiO_(2),NaO_(2)等)的稳定性决定了催化剂的ORR活性/稳定性和电池的整体性能.然而,超氧化物具有高反应活性的特点导致其稳定性难以调控.本文将蒽醌衍生物作为助催化剂,成功实现了超氧化物稳定性的...     

利用生物质材料合成高性能氢氧燃料电池氧还原催化剂（英文）

制备廉价、高活性氧还原催化剂对于发展氢氧燃料电池清洁能源极为重要.在本论文中,我们利用黑木耳作为生物质材料,通过一种便捷的方法合成了高活性氧还原催化剂.黑木耳经水热和热解两个步骤,碳化形成BF-N-950催化剂.该催化剂在酸性和碱性溶液中的半波电势分别为0.77和0.91 V.采用BF-N-950催化剂作为膜电极得到的氢氧燃料单电池,峰值功率可达255 mW cm^-2.本文提出了使用生物质材料合成高性能氧还原催化剂的方法,为氢氧燃料电池的应用提供了有益探索.     

Shape-controlled synthesis of porous AuPt nanoparticles and their superior electrocatalytic activity for oxygen reduction reaction

Control of structure and morphology of Pt-based nanomaterials is of great importance for electrochemical energy conversions. In this work, we report an efficient one-step synthesis of bimetallic porous AuPt nanoparticles (PAuPt NPs) in an aqueous solution. The proposed synthesis is performed by a simple stirring treatment of an aqueous reactive mixture including K₂PtCl₄, HAuCl₄, Pluronic F127 and ascorbic acid at a pH value of 1 without organic solvent or high temperature. Due to their porous structure and bimetallic composition, as-made PAuPt NPs exhibit excellent electrocatalytic activity for oxygen reduction reaction.     

石墨烯负载Pt-Co纳米粒子及其在氧化还原反应中的应用

采用微波-乙二醇方法还原氧化石墨烯和Pt(v)、Co(Ⅱ)粒子混合物,再经300℃H2还原,制备了石墨烯负载Pt-Co合金催化剂(Pt-Co/G).利用透射电镜、X-射线能谱、X-射线衍射和光电子能谱对所制催化剂进行表征.Pt-Co合金的粒径为3nm～8 nm,均匀地分散在石墨烯片上.与单金属的Pt/G和商品化的Pt/C催化剂相比,所制合金化的Pt-Co/G催化剂对氧还原反应展现出高的催化活性和可比拟的稳定性,显示了其在燃料电池中的应用潜力.     

Synthesis and electrocatalytic activity of Au@Pd core-shell nanothorns for the oxygen reduction reaction

Bimetallic core-shell nanostructures with porous surfaces have drawn considerable attention due to their promising applications in various fields, including catalysis and electronics. In this work, Au@Pd core-shell nanothorns （CSNTs） with rough and porous surfaces were synthesized for the first time through a facile co-chemical reduction method in the presence of polyallylamine hydrochloride （PAH） and ethylene glycol （EG） at room temperature. The size, morphology, and composition of Au@Pd CSNTs were investigated by transmission electron microscopy （TEM）, X-ray diffraction （XRD）, energy dispersive spec- troscopy （EDX）, EDX mapping, and X-ray photoelectron spectroscopy （XPS）. The electrochemical properties of as-synthesized Au@Pd CSNTs were also studied by various electrochemical techniques. Au@Pd CSNTs exhibited remarkably high electrocatalytic activity and durability for the oxygen reduction reaction （ORR） in the alkaline media, owing to the unique porous structure and the synergistic effect between the Au core and Pd shell.     

A Co-N/C hollow-sphere electrocatalyst derived from a metanilic CoAl layered double hydroxide for the oxygen reduction reaction,and its active sites in various pH media

Transition-metal-coordinating nitrogen-doped carbon catalysts (M-N/C,M =Co,Fe,Mn,Ni,etc.) are considered one of the most promising nonprecious-metal electrocatalysts for the oxygen reduction reaction (ORR).However,they suffer from low ORR catalytic activity,and their active sites have not been fully identified.Herein,we report the synthesis of a porous Co-N/C hollow-sphere electrocatalyst by carbonization of metanilic anions between the layers of a Co-Al layered double hydroxide.The as-prepared Co-N/C catalyst exhibited excellent ORR catalytic activity with a high half-wave potential and a large diffusion-limited current in alkaline and neutral solutions.The performance of the catalyst was comparable to those of commercial Pt/C electrocatalysts.Through investigating the effects of mask ions (SCN-and F-) on the ORR activity of the Co-N/C catalyst,and comparing the ORR activity before and after the destruction of Co-Nx sites in different pH media,we concluded that the Co-Nx sites act directly as the ORR active sites in acidic and neutral solutions,but have a negligible effect on the ORR activity in alkaline conditions.     

微孔结构氟聚合物铁电驻极体的制备及其热稳定性研究

描述了一种微孔结构氟聚合物铁电驻极体的制备方法，利用准静态方法测量了该功能膜的压电系数如，并通过等温衰减和热刺激放电电流谱的测量研究了凼，的热稳定性。结果表明，这类氟聚合物铁电驻极体膜的准静态压电系数d33与热压时间有关；与聚丙烯（PP）压电驻极体膜相比较，氟聚合物压电驻极体膜不但具有更高的压电活性，而且呈现更优良的热稳定性。     

Construction of multilayers of bare and Pd modified gold nanoclusters and their electrocatalytic properties for oxygen reduction

Abstract

Multilayers of gold nanoclusters (GNCs) coated with a thin Pd layer were constructed using GNCs modified with self-assembled monolayers (SAMs) of mercaptoundecanoic acid and a polyallylamine hydrochloride (PAH) multilayer assembly, which has been reported to act as a three-dimensional electrode. SAMs were removed from GNCs by electrochemical anodic decomposition and then a small amount of Pd was electrochemically deposited on the GNCs. The kinetics of the oxygen reduction reaction (ORR) on the Pd modified GNC/PAH multilayer assembly was studied using a rotating disk electrode, and a significant increase in the ORR rate was observed after Pd deposition. Electrocatalytic activities in alkaline and acidic solutions were compared both for the GNC multilayer electrode and Pd modified GNC electrode.     

甲醛/尿素/TDI三元疏水改性聚乙烯醇的制备及影响因素

采用正交实验方法,研究了甲醛、尿素和甲苯二异氰酸酯对聚乙烯醇的疏水改性,并分析了合成条件对其固含量、黏度、溶出率和交联度的影响.