M-N-C阴极催化剂的制备及其在微生物燃料电池中的应用

以聚苯胺和硝酸盐为前驱体,采用热处理法制备了M-N-C（M=Fe,Co）材料,并将其作为厌氧流化床微生物燃料电池（AFBMFC）阴极催化剂。通过X射线衍射（XRD）、红外光谱（FTIR）、扫描电子显微镜（SEM）对催化剂进行晶型结构和表面形貌的表征。采用循环伏安法（CV）对催化剂的电化学性能进行考察,并应用于AFBMFC,考察了其对电池产电性能的影响。结果表明,使用Fe-N-C催化剂的微生物燃料电池稳定运行时,开路电压达到636.0 mV,功率密度达到166.82 mW·m^-2,比使用Pt/C催化剂的微生物燃料电池的功率密度提高10%。表明Fe-N-C催化剂用做微生物燃料电池阴极催化剂具有潜在的应用前景。     

M-N-C阴极催化剂的制备及其在微生物燃料电池中的应用

以聚苯胺和硝酸盐为前驱体,采用热处理法制备了M-N-C(M=Fe,Co)材料,并将其作为厌氧流化床微生物燃料电池(AFBMFC)阴极催化剂。通过X射线衍射(XRD)、红外光谱(FTIR)、扫描电子显微镜(SEM)对催化剂进行晶型结构和表面形貌的表征。采用循环伏安法(CV)对催化剂的电化学性能进行考察,并应用于AFBMFC,考察了其对电池产电性能的影响。结果表明,使用Fe-N-C催化剂的微生物燃料电池稳定运行时,开路电压达到636.0 mV,功率密度达到166.82 mW·m-2,比使用Pt/C催化剂的微生物燃料电池的功率密度提高10%。表明Fe-N-C催化剂用做微生物燃料电池阴极催化剂具有潜在的应用前景。     

微生物燃料电池阴极催化剂载体的研究进展

微生物燃料电池是在水处理领域中集污水处理与产电功能为一体的新技术。但其产电性能低与其制作成本高制约着微生物燃料电池向实用化发展。因此,提高阴极对氧还原的电化学活性和降低阴极催化剂的制备成本是微生物燃料电池的研究重点之一。本文综述了近年来微生物燃料电池中非生物阴极氧还原催化剂载体的最新研究进展。重点讨论了石墨烯、碳纳米管、碳基材料等作为催化剂载体的种类、电催化性能、催化剂的负载方法以及存在的问题等。其中,经高温加硝酸处理后的碳基材料表面活性提高、导电能力增强,且价格低廉,有望成为微生物燃料电池非生物阴极催化剂载体的推广使用。为开发高效能、低成本的微生物燃料电池非生物阴极提供理论指导。     

微生物燃料电池处理含铬废水并同步产电

以葡萄糖为阳极燃料、含铬废水为阴极液,碳毡为阳极、石墨板为阴极构建了双室微生物燃料电池,考察了阳极条件(底物浓度)及阴极条件(pH、初始六价铬浓度)对含铬废水的降解及MFC的产电性能的影响.结果表明低阴极液pH和高初始Cr(Ⅵ)浓度能改善MFC产电性能.当pH=2、初始六价铬浓度为177 mg/L、反应时间为10 h时,最大输出功率为108 mW/m~2,六价铬去除率为92.8%.阳极底物浓度对微生物燃料电池的性能也有影响.在微生物燃料电池中,阴极极化较小,表明该燃料电池有稳定的性能,微生物燃料电池对含铬废水的处理有应用潜力并能同步产电.     

阳极改性对微生物燃料电池产电及处理废水影响

通过酸浸热处理及搅拌浸渍负载碳粉的方法制备改性碳纸,以此为阳极搭建双室微生物燃料电池(MFC),测试其产电性能及废水处理效果。结果表明,从产电性能来看,酸浸热处理改性碳纸、负载碳粉改性碳纸的最大输出电压为1.144、1.206 V,是未改性碳纸的1.4、1.48倍,最大功率密度分别为14.21、19.92 W/m~2,是未改性碳纸的1.39、1.95倍,产电能力有了较大提高,负载碳粉改性碳纸的MFC产电性能最好;从废水处理效果来看,酸浸热处理改性碳纸和负载碳粉改性碳纸的COD去除率分别为78.6%、78.5%,是未改性碳纸的1.46、1.44倍,二者均有着较好的废水处理效果。     

不同介体厌氧流化床微生物燃料电池产电特性研究

在空气阴极、单室、无膜液固厌氧流化床微生物燃料电池(AFBMFC)中,以污水和椰壳活性炭为液相和固相,分别以亚甲基蓝(MB)、中性红(NR)及铁氰化钾为电子介体,考察电子介体的种类和浓度对厌氧流化床微生物燃料电池产电性能的影响.实验结果表明,亚甲基篮可以提高AFBMFC产电量,但增加幅度较小；添加铁氰化钾后,电池正负极...     

酞菁铁-碳纳米管复合物为阴极催化剂的微生物燃料电池

以循环伏安法(CV)考察酞菁铁/碳纳米管氧还原(ORR)催化行为,并构建以磷酸缓冲溶液(PBS)和葡萄糖为阳极原料,酞菁铁/碳纳米管复合物为阴极氧气还原催化剂的双室型微生物燃料电池(MFCs)。结果表明:(1)在中性介质中,对氧还原的电催化性能要比商品化的铂碳催化剂还原电位正移了44 mV。(2)以大肠杆菌(E coli)为产电微生物,该MFC的最大输出功率密度为932.5 mW/m2,对应电流密度为2792.6 mA/m2,高于铂碳催化剂阴极的MFC。     

改性生物质活性炭空气阴极MDC性能及微生物分析

构建了三室空气阴极微生物脱盐燃料电池(MDC)系统处理榨菜废水。对比了3种阴极催化剂(商品化铂碳(Pt/C)、载锰改性废菌渣活性炭(Mn-MRAC)、铁锰改性废菌渣活性炭(Fe/Mn-MRAC))的MDC产电、脱盐性能及阳极生物膜微生物群落的差异。结果表明,在产电与脱盐性能方面,Mn-MRAC在外电阻1 000Ω的负载下,输出电压、最大功率密度、库伦效率和脱盐速率分别为574 mV、2.59 W/m~3、(26.0±0.9)%和5.39 mg/h,其效果与Pt/C相似,但成本大大降低。Fe/Mn-MRAC的效果则与上述2者相差较大。这为用单金属元素锰改性废菌渣活性炭替代商用铂碳成为空气阴极催化剂提供了实践支持。高通量测序分析表明,3组MDC系统的阳极生物膜中产电菌种类相似但丰度不同,分别为80.93%的(Pt/C)、78.75%的(Mn-MRAC)和72.09%的(Fe/Mn-MRAC)。水解发酵菌属为榨菜废水MDC阳极的核心微生物群落。同时在3组阳极生物膜中发现了反硝化菌属,证明阳极可能存在反硝化反应。     

PEDOT/MWCNTs复合阳极的制备及在MFC中的应用

采用循环伏安法制备聚3,4-乙烯二氧噻吩/多壁碳纳米管(PEDOT/MWCNTs)导电复合物修饰石墨棒阳极,并应用于厌氧流化床微生物燃料电池(AFBMFC)中以考察其产电性能。采用场发射扫描电镜(FESEM)观察复合阳极的表面形貌及断面结构,并用循环伏安法(CV)和交流阻抗法(EIS)测试了碳纳米管加入前后修饰电极的电化学性能变化。结果表明,复合阳极在MFC中运行时,其最大输出功率密度达到217 mW·m^-2,比未加碳纳米管的PEDOT修饰电极提高30%;相应的开路电压为837.8 mV,运行3 d后污水COD去除率达到96.4%,说明在液固流化床对传质的强化作用下,复合阳极在AFBMFC中具有良好的产电性能和污水处理效果,其中碳纳米管的加入在一定程度上提高了复合阳极的导电性及改善了微生物的附着情况。     

碳材料负载金属铂催化剂的制备方法研究

贵金属催化剂在燃料电池、环境保护、石油化工等领域得到广泛应用,因此贵金属催化剂具有很大的发展空间,其中碳材料负载贵金属铂催化剂较为突出。而催化剂的制备方法可以直接影响到其形态、结构和粒径分布,从而影响到催化性能。想要制得的催化剂具有较好催化性能,研究催化剂的制备方法显得尤为重要。本文综合论述制备碳材料负载金属铂催化剂的常用方法、理论原理及相应制备方法的优缺点。     

中温H2S-空气燃料电池阴极催化剂的研究

Abstract Cathode catalysts comprising composite NiO, NiO-Pt, or LiNiO2 have been developed for electro- chemical oxidation of hydrogen sulfide in intermediate-temperature solid oxide fuel cells （ITSOFCs）. All catalysts exhibited good electrical conductivity and catalytic activity at operating temperature. Composite NiO catalysts were found to be more active and have lower over potential and higller current density than pure Pt although the electrical conductivity of NiO itself is lower than that of Pt. This problem has been overcome by either admixing as high as 10% （by mass）Ag powder into NiO_ cathode layer or using composite NiO c atalysts such as NiO-Pt and LiNiO2 catalysts. Composite catalysts like NiO with Ag, electrolyte and starch admixed, NiO-Pt, which was prepared from a mixture of NiO and Pt powders, by admixing electrolyte and starch, and LiNiO2, which is derived from the reaction of LiOH-H2O and NiO with electrolyte and starch admix_ed have been shown to be feasible and effective in an intermediate-temperature H2S-air fuel cell. A fuel cell using Li2SO4-based proton-conducting membrane as electrolyte, metal sulfides as anode catalysts, and composite NiO as cathode catalysts produced a maximum current density about 300mA·cm^-2 and maximum power density over 80 mW-cm-2 at 680℃.     

低负载贵金属催化剂对二甲醚催化燃烧的催化活性

采用浸渍法以g-Al2O3为载体制备了多种低负载量的Pd和Pt催化剂,在微型固定床反应器装置上进行了二甲醚(DME)催化燃烧实验. 考察了不同贵金属负载量的Pd/g-Al2O3和Pt/g-Al2O3催化剂的活性,及浸渍顺序对Pd-Pt/g-Al2O3双金属负载催化剂活性的影响,并测试了贵金属负载摩尔比不同的双金属负载催化剂的活性. Pt负载量0.025%(w)的催化剂在190℃将DME完全燃烧;Pd和Pt共同负载的催化剂[Pd:Pt=2:1(mol), Pt 0.025%(w), Pd 0.027%(w), Pt先负载]性能更好,在175℃将DME完全燃烧;200 h实验后2种催化剂活性降低均小于5%.     

Performance of the Direct Methanol Carbonate Fuel Cell Using Anion Exchange Materials and Non‐Noble Metal Cathode Catalyst

A direct methanol fuel cell using a mixture of O₂ and CO₂ at the cathode was evaluated using anion exchange materials and cathode catalysts of Pt and a non‐Pt catalyst. The MEA based on non‐noble metal catalyst Acta 4020 showed superior performance than Pt/C based MEA in terms of open circuit potential and power density in carbonate environment. The fuel cell performance was improved by applying anion exchange ionomer in the catalyst layer. A maximum power density of 4.5 mW cm^–2 was achieved at 50 °C using 6.0 M methanol and 2.0 M K₂CO₃.     

Palladium-based electrodes: A way to reduce platinum content in polymer electrolyte membrane fuel cells

To decrease the Pt content, a polymer electrolyte membrane fuel cell (PEMFC) was formed using a carbon supported Pd₉₆Pt₄ catalyst as the anode material, and a carbon supported Pd₄₉Pt₄₇Co₄ catalyst as the cathode material. The as-obtained Pd-based PEMFC with an overall Pd:Pt:Co atomic composition of electrodes (anode + cathode) = 72:26:2 exhibited a performance not too far from that of the fuel cell with the conventional 100% Pt electrodes. With a Pt content of 35 wt% of that of the cell with full Pt electrodes, at a current density of 1 A cm⁻² the performance loss of the cell with the Pd-based catalysts was only 11%, with 6% ascribed to the anode catalyst and 5% to the cathode catalyst. The maximum power density of the Pd-based cell was 76% of that of the cell with Pt catalysts.     

Sulfonated polyaniline nanofiber as Pt-catalyst conducting support for proton exchange membrane fuel cell

Carbonization at high temperature can significantly increase the conductivity of polyaniline nanofibers (PANF) but the created carbonized surface is too hydrophobic for Pt-loading. Sulfonic acid groups are then grafted on the carbonized PANF by ultra-sonication in concentrated sulfuric acid to increase the surface hydrophilicity and Pt-loading. The obtained sulfonated carbonized PANF was found to own not just high conductivity but good hydrophilicity which can load more than 18% of Pt on the surface from a 25% H₂PtCl₆(aq) and demonstrate better electrochemical activity in the cyclic voltaic and ORR testing. The surface area of the loaded Pt per unit support can be increased from 85.66 to 276.61 cm² mg⁻¹ after 24 h of sulfonation. The single cell performance demonstrates an increasing power and maximum current density with degree of sulfonation for MEA made of the sulfonated carbonized PANF.     

The improved methanol tolerance using Pt/C in cathode of direct methanol fuel cell

Membrane electrode assemblies (MEA) were prepared using PtRu black and 60 wt.% carbon-supported platinum (Pt/C) as their anode and cathode catalysts, respectively. The cathode catalyst layers were fabricated using various amounts of Pt (0.5 mg cm⁻², 1.0 mg cm⁻², 2.0 mg cm⁻², and 3.0 mg cm⁻²). To study the effect of carbon support on performance, a MEA in which Pt black was used as the cathode catalyst was fabricated. In addition, the effect of methanol crossover on the Pt/C on the cathode side of a direct methanol fuel cell (DMFC) was investigated. The performance of the single cell that used Pt/C as the cathode catalyst was higher than single cell that used Pt black and this result was pronounced when highly concentrated methanol (above 2.0 M) was used as the fuel.     

Application of iron-based cathode catalysts in a microbial fuel cell

Catalysts for the oxygen reduction reaction (ORR) in a microbial fuel cell (MFC) were prepared by the impregnation on carbon black of Fe^II acetate (FeAc), Cl–Fe^III tetramethoxyphenyl porphyrin (ClFeTMPP), and Fe^II phthalocyanine (FePc). These materials were subsequently pyrolyzed at a high temperature. The ORR activity of all Fe-based catalysts was measured at pH 7 with a rotating disk electrode (RDE) and their performance for electricity production was then verified in a continuous flow MFC. Catalysts prepared with FeAc and pyrolyzed in NH₃ showed poor activity in RDE tests as well as a poor performance in a MFC. The ORR activity and fuel cell performance for catalysts prepared with ClFeTMPP and FePc and pyrolyzed in Ar were significantly higher and comparable for both precursors. The iron loading was optimized for FePc-based catalysts. With a constant catalyst load of 2 mg cm⁻² in a MFC, the highest power output (550–590 mW/m²) was observed when the Fe content was 0.5–0.8 wt%, corresponding to only 0.01–016 mg Fe/cm². A similar power output was observed using a Pt-based carbon cloth cathode containing 0.5 mg Pt/cm². Long-term stability of the Fe-based cathode (0.5 wt% Fe) was confirmed over 20 days of MFC testing.     

Gas diffusion electrodes containing sulfonated polyether ionomers for PEFCs

Gas diffusion electrodes (GDEs) containing sulfonated polyether (SPE) ionomers as proton conducting binder have been prepared and evaluated in H₂/O₂ polymer electrolyte fuel cells. An autoclave treatment has been applied for the first time to a hydrocarbon ionomer for the preparation of GDEs. The GDEs worked well as anode without practical overpotential up to 800 mA/cm² of the current density. As cathode, the GDEs showed significant dependence on the SPE content and its ion exchange capacity (IEC). Higher catalyst utilization was achieved for the GDEs with higher SPE content due to enhanced proton conduction. Cyclic voltammetry implied higher catalyst utilization of the SPE-based GDEs than that of the conventional Nafion^®-based GDEs. Scanning transmission electron microscopy (STEM) revealed that the SPE ionomer coated uniformly on the surface of Pt/carbon black catalysts. Humidification conditions affect proton conductivity and swelling of the SPE ionomer and thus were crucial for the cathode performance. SPE ionomer with medium IEC (2.17 meq/g) served best in GDEs in terms of catalyst utilization.     

Preparation of cost-effective Pt–Co electrodes by pulse electrodeposition for PEMFC electrocatalysts

Low loading platinum–cobalt (Pt–Co) cathode catalyst on a Nafion(Na⁺)-bonded carbon layer is fabricated by using galvanostatic pulse technique to show the advantage of electrodeposition for high utilization of catalyst in proton exchange membrane fuel cell (PEMFC). We observed that Pt–Co catalysts evenly exist on the surface of carbon electrode and its thickness is about 5.8 μm, which is four times thinner than conventional Pt/C. Improved single cell power performance of Pt–Co cathode catalysts with a ratio of 3.2:1 compared with Pt/C is clearly presented.