直接甲醇燃料电池阳极电催化剂材料的研究

评述了直接甲醇燃料电池阳极电催化剂研究中的几个热点问题 ,简述了催化剂材料的制备方法和最新的发展情况 ,概述了铂基二元、三元、四元催化剂材料的研究现状、取得的主要成果和存在的主要问题 ;铂基钙钛矿类和非铂基催化剂的成本低 ,但需要进一步解决在酸性介质中的寿命短和活性低的问题。     

聚乙烯醇-聚丙烯酸共混膜的阻醇及质子导电性能研究

针对目前直接甲醇燃料电池 (DMFC)中普遍使用的Nafion系列全氟磺酸膜存在的甲醇穿透问题 ,制备了在渗透蒸发醇 -水分离领域有良好分离效果的聚乙烯醇 (PVA)和聚乙烯醇 -聚丙烯酸 (PVA -PAA)共混膜并研究了其阻醇和质子导电性能 .与Nafion1 1 7膜相比 ,PVA膜和PVA -PAA共混膜的阻醇性能有明显提高 ,其导电能力虽很大程度上依赖于外加电解质溶液 ,但PAA的混入使PVA膜材料的导电性能有了很大改善     

Nafion~膜的回收及再铸膜在直接甲醇燃料电池中的应用

利用异丙醇水溶液溶解废弃Nafio n膜,异丙醇体积分数在60%~75%之间的水溶液能在220℃相对较快的溶解Nafio n膜制得溶液,利用二甲基亚砜(DMSO)作为溶剂制备再铸膜。再铸膜酸度(EW)和溶胀度(SW)测试结果接近商品膜数值;红外光谱、X射线衍射分析表明再铸膜具有与商品膜相似的结构;甲醇渗透、电池性能测定结果表明,与商品Na-fio n115膜相比,具有相同厚度的再铸膜降低了甲醇渗透,适合应用于直接甲醇燃料电池中。     

PAMPS/PVA复合质子交换膜的电导率及阻醇性能

制备了聚2-丙烯酰胺-2-甲基丙磺酸(PAM PS)/聚乙烯醇(PVA)复合质子交换膜,并研究了膜的组成、甲醇水溶液浓度等对膜力学强度、电导率和甲醇渗透率的影响。实验发现,当PAM PS含量为50%时,此复合膜拉伸强度可达21.8 M Pa,电导率σ可达1.5×1-0 2S/cm,并且甲醇透过率P仅为9.8×1-0 8cm2/S。     

炭载Pt-P催化剂对甲醇氧化的电催化性能研究

通过NaH2PO2自分解方法制备了高分散性的Pt-P/C催化剂,并且使用X射线衍射(XRD)、透射电子显微镜(TEM)等表征手段对催化剂进行了表征,NaH2PO2的加入可有效降低催化剂的粒径,约为2.3nm。此外,亦用多种电化学测试手段测试了P的掺杂对甲醇的电催化氧化性能的影响,测试结果表明PtP/C催化剂不但能够增强催化剂对甲醇催化氧化的活性,而且还能够提高催化剂的稳定性。该测试结果表明Pt-P/C催化剂是一类具有潜在应用前景的直接甲醇燃料电池阳极催化剂。     

The improvement of methanol oxidation using nano-electrocatalysts

ABSTRACT

In this study, a nano-scale perovskite LaMnO₃ (LaMnO₃NPs) was synthesised by a rapid microwave-assisted co-precipitation method and characterised by X-ray powder diffraction, Fourier transform infrared, scanning electron microscopy and energy dispersive X-ray techniques. A modified glassy carbon electrode with Pt nanoparticles (PtNPs), functionalised multi-walled carbon nanotubes (CNTs) and LaMnO₃NPs as multifunctional catalyst was prepared and furthermore, its catalytic activity toward methanol oxidation was investigated. Based on the electrochemical studies, the PtNPs–CNTs–LaMnO₃NPs nanocomposite showed considerable activity for methanol oxidation in comparison to PtNPs, PtNPs–CNTs and PtNPs–LaMnO₃NPs. The results displayed the adding of CNTs and LaMnO₃NPs into PtNPs catalyst and the use of a more porous matrix of chitosan can improve the anode performance for methanol oxidation. The transition metals presence at catalyst structure caused to catalyse the methanol dehydrogenation. The decreasing the poisoning rate of the PtNPs with intermediates and by-products of anodic reaction was observed due to the bi-functional effect electrical and oxygen ion conductive perovskite. Direct methanol fuel cell (DMFC) was designed, assembled and tested with suggested PtNPs–CNTs–LaMnO₃NPs nanocomposites as anodic catalyst at variety conditions. The effect of experimental factors such as temperature and methanol concentration on DMFC performances was investigated and optimised.     

直接甲醇燃料电池用磷酸掺杂PAN复合膜的研究

本文研究了聚丙烯腈-磷酸(PAN-xH3PO4)复合质子交换膜的结构、聚合物与酸之间的相互作用、甲醇渗透性能以及质子导电性能。结果表明。PAN-xH3PO4复合膜与Nation膜的甲醇渗透率相差不大。但是比聚丙烯腈膜的甲醇渗透率高两个数量级左右，而且随甲醇浓度增加而增加；PAN-xH3PO4复合膜具有较好的质子导电能力。电导率随频率(时间)的变化很小，其质子导电性能主要依赖于聚合物与酸的相互作用。     

直接甲醇燃料电池用质子交换膜研究进展

目前,全氟磺酸系列膜（如Nafion系列膜）在直接甲醇燃料电池（DMFC）中得到较为广泛的应用,但其成本较高;阻醇性能差;在膜内水含量较低或温度高于100℃又无水补充时,电导率会明显下降,不利于高温（〉100℃）DMFC运行,因此,专家学者们正在研究、开发阻醇的廉价的质子交换膜,对近两三年各国研究的应用于DMFC中的阻醇的廉价的质子交换膜进行简要介绍和性能比较。     

羟基锡酸盐载铂复合催化剂Pt/(Co,Zn)Sn(OH)6的合成及其甲醇电催化氧化性能

以羟基锡酸盐CoSn（OH）₆和ZnSn（OH）₆纳米空心立方体为前体,采用抗坏血酸作为弱还原剂,经过超声过程分别合成了羟基锡酸钴载Pt/CoSn（OH）₆和羟基锡酸锌载Pt/ZnSn（OH）₆复合催化剂,并在甲醇氧化反应（MOR）中表现出良好的性能。Pt/CoSn（OH）₆和Pt/ZnSn（OH）₆催化剂的单位质量活性分别为1 095.6 mA/mg和699.5 mA/mg,高于C载Pt（Pt/C）的594.6 mA/mg。利用XRD、SEM、TEM、XPS和电化学测试对催化剂晶体结构和性能间的关系进行了探索。CO溶出实验结果表明,羟基锡酸盐载体有利于Pt表面CO的去除,载体与Pt间的强相互作用和载体表面的大量羟基基团增强了催化剂的催化活性和CO抗毒性。此外,Pt/（Co,Zn）Sn（OH）₆催化剂中单质Pt高的相对含量也有利于提高MOR活性。通过研究载铂羟基锡酸盐电催化氧化甲醇性能,能够揭示载体结构对催化性能的影响,有助于羟基锡酸盐载铂复合催化剂在直接甲醇燃料电池（DMFCs）领域的应用。     

Flexible All-Solid-State Direct Methanol Fuel Cells with High Specific Power Density

It is vital to create flexible batteries as power sources to suit the needs of flexible electronic devices because they are widely employed in wearable and portable electronics. The direct methanol fuel cell (DMFC) is a desirable alternative portable energy source since it is a clean, safe, and high energy density cell. The traditional DMFC in mechanical assembly and its unbending property, however, prevent it from being employed in flexible electrical devices. In this study, the flexible membrane electrode assembly (MEA) with superior electrical conductivity and nanoscale TiC-modified carbon cloth (TiC/CC) is used as supporting layer. Additionally, solid methanol fuels used in the manufacturing of flexible all-solid-state DMFC have the advantages of being tiny, light, and having high energy density. Furthermore, the DMFC's placement and bending angle have little effect on its performance, suggesting that DMFC is appropriate for flexible portable energy. The flexible all-solid-state DMFC's power density can reach 14.06 mW cm⁻², and after 50 bends at 60°, its voltage loss can be disregarded. The flexible all-solid DMFC has an energy density that is 777.78 Wh Kg⁻¹ higher than flexible lithium-ion batteries, which is advantageous for the commercialization of flexible electronic products.     

Preparation of a platinum electrocatalyst by coaxial pulse arc plasma deposition

We have developed a new method of preparing Pt electrocatalysts through a dry process. By coaxial pulse arc plasma deposition (CAPD), highly ionized metal plasma can be generated from a target rod without any discharged gases, and Pt nanoparticles can be deposited on a carbon support. The small-sized Pt nanoparticles are distributed over the entire carbon surface. From transmission electron microscopy (TEM), the average size of the deposited Pt nanoparticles is estimated to be 2.5 nm, and their size distribution is narrow. Our electrocatalyst shows considerably improved catalytic activity and stability toward methanol oxidation reaction (MOR) compared with commercially available Pt catalysts such as Pt black and Pt/carbon (PtC). Inspired by its very high efficiency toward MOR, we also measured the catalytic performance for oxygen reduction reaction (ORR). Our PtC catalyst shows a better performance with half-wave potential of 0.87 V, which is higher than those of commercially available Pt catalysts. The higher performance is also supported by a right-shifted onset potential. Our preparation is simple and could be applied to other metallic nanocrystals as a novel platform in catalysis, fuel cells and biosensors.     

二氧化碳中甲醇和乙醇的吸附分离

利用酒精厂尾气生产食品级二氧化碳需要脱除甲醇和乙醇.考察了二氧化碳中甲醇、乙醇在活性炭、ZSM-5、5A、NaY分子筛不同吸附剂上的动态吸附性能,讨论了吸附质分子极性、分子直径、吸附剂的表面极性、孔道结构等因素对吸附过程的影响.     

Ni、Co、Mn、Cu掺杂对K4 Nb6 O17光催化活性的影响

通过高温固相反应合成了铌酸盐K4Nb6O17及Ni2 、Co3 、Mn4 、Cu2 (5.0%mol)掺杂的K4Nb6O17并采用X射线衍射、紫外可见漫反射光谱、扫描电镜、比表面积分析等对其进行了结构和形貌表征.在甲醇为电子给体、Pt为助催化剂的情况下,研究了K4Nb6O17及Ni2 、Co3 、Mn4 、Cu2 掺杂的K4Nb6O17作为催化剂在约400nm紫外辐射下分解水产氢的光催化活性,并讨论了引起催化剂活性差异的原因.     

Preparation of a platinum electrocatalyst by coaxial pulse arc plasma deposition

Abstract

We have developed a new method of preparing Pt electrocatalysts through a dry process. By coaxial pulse arc plasma deposition (CAPD), highly ionized metal plasma can be generated from a target rod without any discharged gases, and Pt nanoparticles can be deposited on a carbon support. The small-sized Pt nanoparticles are distributed over the entire carbon surface. From transmission electron microscopy (TEM), the average size of the deposited Pt nanoparticles is estimated to be 2.5 nm, and their size distribution is narrow. Our electrocatalyst shows considerably improved catalytic activity and stability toward methanol oxidation reaction (MOR) compared with commercially available Pt catalysts such as Pt black and Pt/carbon (PtC). Inspired by its very high efficiency toward MOR, we also measured the catalytic performance for oxygen reduction reaction (ORR). Our PtC catalyst shows a better performance with half-wave potential of 0.87 V, which is higher than those of commercially available Pt catalysts. The higher performance is also supported by a right-shifted onset potential. Our preparation is simple and could be applied to other metallic nanocrystals as a novel platform in catalysis, fuel cells and biosensors.     

重铬酸钾法测定生物柴油副产物粗甘油中甲醇含量

建立了重铬酸钾测定粗甘油中甲醇含量的方法,研究了H+浓度、加热时间对实验的影响。结果表明,在H+浓度为11.04 mol·L-1,加热回流25min,甲醇可被重铬酸钾定量的氧化成二氧化碳,用硫酸亚铁铵滴定过量的重铬酸钾。加标回收率在97.3%—102.5%,样品测定结果的相对标准偏差低于2%。     

溶剂对溶液法制备的SPEEK质子交换膜性能的影响

本文在聚醚醚酮(PEEK)磺化反应制备相同磺化度的磺化聚醚醚酮(SPEEK)基础上,采用不同的溶剂通过溶液法制备一系列SPEEK质子交换膜,采取交流阻抗法、扩散池法和溶胀法分别评价其导质子能力、阻醇性能和溶液稳定性,探讨溶剂种类对SPEEK质子交换膜性能的影响规律.试验结果表明溶剂对所制备膜的导质子能力和阻醇性能影响依赖于溶剂分子与SPEEK中磺酸基团的相互作用,若存在越强作用,膜的导质子能力越弱,而阻醇性能越高.此外,溶剂种类对膜的吸水溶胀性能存在较小的影响,对膜表面的微孔形态存在明显的影响,并与膜的导质子能力及阻醇性能存在对应关系.综合比较不同溶剂制备膜的导质子能力、阻醇性能和吸水溶胀性能,DMAc是优于DMF和DMSo的制膜溶剂.     

直接甲醇燃料电池用磺化聚醚醚酮质子交换膜

在回顾近年来直接甲醇燃料电池用磺化聚醚醚酮(SPEEK)质子交换膜的发展历程基础上,分别综述了制膜材料SPEEK的合成和SPEEK质子交换膜的制备研究进展,重点总结了SPEEK质子交换膜的电导率和阻醇性能及其稳定性的影响因素和影响规律,其中包括制膜材料和溶剂以及工艺、SPEEK的共混改性、SPEEK的填充改性或多层复合结构的影响,进而分析了高性能SPEEK质子交换膜的开发研究前景.     

磺化杂萘联苯聚醚酮膜的制备及其阻醇和质子导电性能

采用浓硫酸和发烟硫酸的混合物作磺化剂得到不同磺化度的磺化杂萘联苯聚醚酮（SPPEK）,考察了不同磺化度的SPPEK膜的导电和阻醇特性．磺化度为73％的膜在测试的温度范围内膜的电导率数量级在10^-2S／cm,其甲醇透过系数约比Nafion 115膜低一个数量级,如果以质子传递通量和甲醇传递通量之比定义为综合指标,SPPEK膜的综合性能比Nafion 115膜高3．3倍。     

磺化聚醚醚酮/蒙脱土复合型质子交换膜制备与性能

以磺化聚醚醚酮(SPEEK)为基体,以有机改性的蒙脱土(OMMT)为无机相,采用溶液插层法成功制备出了可望应用于直接甲醇燃料电池的SPEEK/OMMT复合型质子交换膜.通过X射线衍射(XRD)表征了复合膜的微观结构,并采用交流阻抗和隔膜扩散方法分别考察了复合膜的质子传导性能和阻醇性能.结果表明,蒙脱土的片层间距超过4.4 nm,SPEEK高分子链已插层到蒙脱土片层之间.与纯SPEEK膜相比,SPEEK/OMMT复合膜的质子传导率有所降低,但在90℃也达到了1.2×10-2S/cm的水平,而且蒙脱土的加入明显地降低了SPEEK膜的甲醇渗透率.