共查询到20条相似文献,搜索用时 46 毫秒
1.
Pt 45Ru 45M 10/C (M = Fe, Co, and Ni) catalysts were synthesized and physical and electrochemical properties were analyzed by XRD, TEM, CO stripping and methanol electro-oxidation activity measurement. Among these catalysts, the Pt 45Ru 45Fe 10/C catalyst exhibited the highest mass activity of 2.6 A/g catal. while those of the Pt 45Ru 45Co 10/C and Pt 45Ru 45Ni 10/C catalysts were 2.2 and 2.5 A/g catal., respectively. In the case of specific activity, the catalysts exhibited much higher activities of 110 (130%), 120 (140%) and 150 (170%) mA/m 2 for the Fe, Co and Ni incorporated catalysts, respectively, than 88 mA/m 2 of a commercial PtRu/C catalyst. 相似文献
2.
The synthesis, physical characterization, decontamination and some electrocatalytic properties of PtRu nanoparticles prepared using the microemulsion method are reported. The nanoparticles are synthesized by reduction with sodium borohydride of H 2PtCl 6 and RuCl 3 in a water-in-oil microemulsion of water/polyethylenglycol-dodecylether (BRIJ ® 30)/ n-heptane. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and energy dispersive analysis by X-rays (EDAX) experiments were carried out to characterize the single and bimetallic nanoparticles obtained. Cyclic voltammograms (CV) of clean nanoparticles were obtained after a controlled decontamination procedure of their surfaces. CO adsorption–oxidation and methanol electrooxidation were used as test reactions to check the electrocatalytic behaviour of the bimetallic nanoparticles. Pt 80Ru 20 (nominal atomic composition) nanoparticles are the best electrocatalyst for both CO ad and methanol oxidation. All these results show that the microemulsion method can be used to produce bimetallic nanoparticles in a very easy way. The method can be very easily scaled-up for industrial use. 相似文献
4.
Proton conducting solid oxide fuel cell (H-SOFC) is an emerging energy conversion device, with lower activation energy and higher energy utilization efficiency. However, the deficiency of highly active cathode materials still remains a major challenge for the development of H-SOFC. Therefore, in this work, K 2NiF 4-type cathode materials Pr 2-xBaNi 0.6Cu 0.4O 4+δ ( x=0, 0.1, 0.2, 0.3), single-phase triple-conducting (e -/O 2-/H +) oxides, are prepared for intermediate temperature H-SOFCs and exhibit good oxygen reduction reaction activity. The investigation demonstrates that doping Ba into Pr 2-xBaNi 0.6Cu 0.4O 4+δ can increase its electrochemical performance through enhancing electrical conductivity, oxygen vacancy concentration and proton conductivity. EIS tests are carried at 750℃ and the minimum polarization impedances are obtained when x=0.2, which are 0.068 Ω·cm 2 in air and 1.336 Ω·cm 2 in wet argon, respectively. The peak power density of the cell with Pr 1.8Ba 0.2Ni 0.6Cu 0.4O 4+δ cathode is 298 mW·cm -2 at 750℃ in air with humidified hydrogen as fuel. Based on the above results, Ba-doped Pr 2-xBaNi 0.6Cu 0.4O 4+δ can be a good candidate material for SOFC cathode applications. 相似文献
5.
通过柠檬酸-EDTA络合法制备固体氧化物燃料电池阴极材料La 0.6Sr 0.4Co 0.2Fe 0.8O 3-δ(LSCF)粉体。以Sm 0.2Ce 0.8O 1.9(SDC)为电解质,制备了LSCF/SDC/LSCF对称电极。采用浸渍法在LSCF/SDC/LSCF两侧浸渍La(NO 3) 3、Ni(NO 3) 2、Fe(NO 3) 3混合溶液,850℃烧结后得到表面修饰后的阴极材料。研究了浸渍烧结后表面修饰阴极材料的物相结构特征、电化学交流阻抗、电化学催化活性及单电池输出性能。结果表明:通过浸渍法在LSCF阴极表面形成了与LSCF结构相似的La 0.62Sr 0.38Ni 0.03Co 0.19Fe 0.78O 3-δ(LSNCF)固溶体,在表面产生的纳米颗粒提升了阴极材料对O2的吸附解离能力,并表现出较低的极化阻抗,在800℃时LSNCF阴极材料的极化面电阻为0.083Ω·cm 2,在800℃连续工作7 200 min后,LSNCF阴极材料对称电池极化阻抗为0.117Ω·cm 2。以Ni-SDC为阳极,SDC为电解质,LSNCF为阴极组装阳极支撑单电池,在750℃时最大功率密度为693 m W/cm 2。 相似文献
6.
Carbon supported Pt–Sn alloy catalysts were prepared by reduction of Pt and Sn precursors with formic acid, and their electrocatalytic activity for methanol oxidation was compared with commercial Pt/C and Pt 75Sn 25/C electrocatalysts. By X-ray diffraction analysis it was found that the Pt lattice parameter increases with the addition of Sn, indicative of alloy formation. It was confirmed that Sn exhibits cocatalytic activity for CO oxidation. The onset potential for the methanol oxidation reaction of the Pt–Sn electrode was approximately 0.1 V smaller than that on Pt both at room temperature and at 90 °C. The best performance in a direct methanol fuel cell was obtained using the Pt 75Sn 25/C alloy catalyst prepared by the formic acid method as the result of an optimal balance of Sn content, degree of alloying and metal particle size. 相似文献
7.
In this work the novel use of urea combustion synthesis as a straightforward method for the preparation of a trimetallic alloy, 60 Pt–30 Ru–10 Co (mol%) is described. A novel composition in the Pt–Ru–Co ternary system has been considered for a possible substitution of commercial anode catalysts in PEMFC. The specific surface area (102 m 2/g) of the carbon supported catalysts produces anodes which gave power density stable values of 260 mW/cm 2. The XPS (X-ray Photoelectron Spectrometry) data showed that combustion synthesis produces Platinum and Cobalt segregated in the catalyst’s surface, these metals are layered structured and exhibit different oxidation states. 相似文献
8.
The addition of Au/TiO 2 and zeolites as active components to PtRu/C electrode in DMFC was investigated by using combinatorial high-throughput-screening test. Addition of Au/TiO 2 to PtRu/C electrode, especially in the ratio of PtRu/C: Au/TiO 2 9:1, 8:2, 7:3, were effective to improve the performance of direct methanol fuel cell. The electrochemical properties of the prepared electrodes were compared using cyclic voltammetry, impedance spectroscopy and a single cell performance test of a direct methanol fuel cell (DMFC). The adsorbed CO on Pt might be easily oxidized on the surface of Au/TiO 2 by interaction between PtRu/C and Au/TiO 2. The addition of the solid acid proton conducting materials (ZSM-5) on PtRu/C anode leads to the high temperature operation. The cell performance was maintained over the cell temperature 120 °C (maximum current density was 200 mA/cm 2 at 160 °C) by the addition of ZSM-5 as proton conducting materials. 相似文献
9.
Initial tests have been carried out with the fuel cell arrangement La 0.6Sr 0.4Co 0.2Fe 0.8O 3Ce 0.9Gd 0.1O 1.95Ni/YSZ, incorporating dense film (5–10 μm) Ce 0.9Gd 0.1O 1.95 electrolyte tape cast onto the supporting anode, to investigate the feasibility of intermediate temperature operation (500–700°C). A good open circuit voltage of approx. 0.8 V was obtained at 550°C using moist hydrogen as the fuel. Slightly lower open circuit voltages were found at higher temperatures, which may have been caused by minor gas leakage and the electronic conductivity of the electrolyte. Power outputs in excess of 100 mW/cm 2 were obtained at 650°C, and the cell resistance was 0.8Ω cm 2 at this temperature. This resistance, and the greater resistance at lower temperature, was predominantly due to the cathode according to AC impedance measurements. Experiments were also carried out at 600°C using direct methanol fuels at the anode; the maximum power output was approximately half of that obtained with hydrogen. 相似文献
10.
质子交换膜燃料电池膜电极中的微孔层结构对改善体系的水管理能力,提升膜电极的整体性能发挥重要作用。本文通过静电纺丝和后续热处理的方法制备了多孔纳米碳纤维(PCNF),并以此构建膜电极的微孔层。与炭黑颗粒作为微孔层呈现出紧密堆积结构不同,由PCNF搭建的微孔层结构疏松呈现三维贯通状。膜电极的发电测试表明,以多孔纳米碳纤维作为微孔层(MPL-PCNF)的膜电极其最大功率密度达70.0mW/cm 2,远高于炭黑颗粒为微孔层(MPL-CB)的膜电极(58.1mW/cm 2),而没有微孔层(Ref)结构的膜电极最大功率密度仅为27.7mW/cm 2,显示出PCNF作为微孔层材料的明显优势。 相似文献
11.
Tin oxide–silica composite aerogels were successfully prepared with a co-fed precursor sol–gel process. The crystallinity of the tin oxide nanoparticles, embedded in the mesoporous SiO 2 network, was improved with increasing the post-reaction thermal treatment temperature. The composite aerogels exhibited a rich photoluminescence (PL) emission contributed by both SnO 2 and SiO 2. The PL peak of 346 nm was from the near band edge emission of the tin oxide nanoparticles, and the ones located at 310 and 476 nm were attributable to the oxygen deficiencies of the silica network. Three more emission peaks, 387, 432, and 522 nm, were observed, with the 387 nm peak contributed by the oxygen vacancies V O++, the 432 nm peak by the Sn interstitials, and the 522 nm peak by the oxygen vacancies V O+, respectively, of the tin oxide nanoparticles. The intensities of these three defect level emissions were found decreased, as compared to that of the near band edge emission, with increasing the post-reaction thermal treatment temperature as the tin oxide crystallinity improved. 相似文献
12.
The purpose of the present work was to prepare nanometric brown pigments spinel (Zn 1−xNi x)Fe 2O 4 (with x = 0, 0.5 and 1 mol of the Ni 2+) structures by combustion reaction and characterize the resulting powders. The compositions were prepared by a single-step solution combustion reaction using nitrates and urea as fuel. Stoichiometric compositions of metal nitrate and urea were calculated using the total oxidizing and reducing valences of the components, which serve as the numerical coefficients for the stoichiometric balance, so that the equivalence ratio Φc is equal to unity and the energy released was maximum. The resulting powders were characterized by X-ray diffraction (XRD), nitrogen adsorption by BET, scanning electron microscopy (SEM), helium pycnometry, sedimentation, transmission electron microscopy (TEM), and CIE- L* a* b* color-measurements. The results demonstrated that the synthesis by combustion reaction was very fast and safe resulting in crystalline spinel containing nanoparticles (18–26 nm) for all of the compositions studied. The results demonstrate the viability of using these powders as brown ceramic pigments. 相似文献
13.
化工副产气是具有一定热值的可燃性复杂气体,但一直以来提纯再利用经济效益低,大多采用直接燃烧的方法处理。针对当前化学工业开展绿色低碳转型的需求,研究了固体氧化物燃料电池(SOFC)采用化工副产气发电的性能。以SrTi 0.3Fe 0.7O 3-δ (STF)钙钛矿氧化物为基础,采用高温固相合成法制备了B位Co掺杂的Sr 0.95Ti 0.33Fe 0.6Co 0.07O 3-δ (STFC)阳极,以不同种类和组成的模拟化工副产气作为燃料,系统研究了单电池的电化学性能和稳定性。结果表明,STFC钙钛矿氧化物在加湿氢气中还原后原位析出Co 0.28Fe 0.72纳米合金颗粒;以其为阳极的SOFC单电池在多种模拟化工副产气燃料下实现了高性能运行,表现出较小的极化阻抗和良好的电化学性能输出;在含有多种碳氢组分的复杂燃料下表现出卓越的长期运行稳定性。 相似文献
14.
Green phosphors of the composition Ce 1- x Tb x MgAl 11O 19 (0.1 < x < 0.6) were prepared via self-propagating (combustion) synthesis, using urea as a fuel. The phosphors that were produced via the combustion route were fine powders and produced a luminous intensity of 72%, compared to an optimized commercial phosphor. The excitation spectra were characteristic of the Ce 3+ cation; however, no Ce 3+ emission was observed. Energy transfer from the Ce 3+ cation to the Tb 3+ cation was complete, and only the 542 nm Tb 3+ emission was observed. Concentration quenching occurred with x > 0.5. Scanning electron microscopy images showed a well-crystallized, platelike morphology, with a particle size of 10-20 µm. 相似文献
15.
化工副产气是具有一定热值的可燃性复杂气体,但一直以来提纯再利用经济效益低,大多采用直接燃烧的方法处理。针对当前化学工业开展绿色低碳转型的需求,研究了固体氧化物燃料电池(SOFC)采用化工副产气发电的性能。以SrTi 0.3Fe 0.7O 3-δ (STF)钙钛矿氧化物为基础,采用高温固相合成法制备了B位Co掺杂的Sr 0.95Ti 0.33Fe 0.6Co 0.07O 3-δ (STFC)阳极,以不同种类和组成的模拟化工副产气作为燃料,系统研究了单电池的电化学性能和稳定性。结果表明,STFC钙钛矿氧化物在加湿氢气中还原后原位析出Co 0.28Fe 0.72纳米合金颗粒;以其为阳极的SOFC单电池在多种模拟化工副产气燃料下实现了高性能运行,表现出较小的极化阻抗和良好的电化学性能输出;在含有多种碳氢组分的复杂燃料下表现出卓越的长期运行稳定性。 相似文献
16.
Carbon nanotubes supported iron catalysts were prepared by incipient wetness, deposition/precipitation using K 2CO 3, and deposition/precipitation using urea. The incipient wetness method and the deposition/precipitation technique using urea yielded highly dispersed Fe 3+ on the carbon nanotubes support. The deposition/precipitation technique using K 2CO 3 also yielded larger Fe 2O 3-crystallites. After reduction the three catalysts had similar metal surface areas. Nevertheless, the activity of these catalysts in the Fischer–Tropsch synthesis differed significantly with the catalyst prepared by incipient wetness being the most active one. It is speculated that the differences in the performance of the catalysts might be attributed to the different crystallite size distributions, which would result in a variation in the amount of the different phases present in the catalyst under reaction conditions. The selectivity in the Fischer–Tropsch synthesis over the three catalysts seems to be independent of the method of preparation. 相似文献
17.
The solubility of Pd(NO 3) 2 in water is moderate whereas it is completely soluble in diluted HNO 3 solution. Pd/MIL-101(Cr) and Pd/MIL-101-NH 2(Cr) were synthesized by aqueous solution of Pd(NO 3) 2 and Pd(NO 3) 2 solution in dilute HNO 3 and used for CO oxidation reaction. The catalysts synthesized with Pd(NO 3) 2 solution in dilute HNO 3 showed lower activity. The aqueous solution of Pd(NO 3) 2 was used for synthesis of mono-metal Ni, Pd and bimetallic PdNi nanoparticles with various molar ratios supported on MOF. Pd 70Ni 30/MIL-101(Cr) catalyst showed higher activity than monometallic counterparts and Pd+ Ni physical mixture due to the strong synergistic effect of PdNi nanoparticles, high distribution of PdNi nanoparticles, and lower dissociation and desorption barriers. Comparison of the catalysts synthesized by MIL-101(Cr) and MIL-101-NH 2(Cr) as the supports of metals showed that Pd/MIL-101-NH 2(Cr) outperforms Pd/MIL-101-(Cr) because of the higher electron density of Pd resulting from the electron donor ability of the NH 2 functional group. However, the same activities were observed for Pd 70Ni 30/MIL-101(Cr) and Pd 70Ni 30/MIL-101-NH 2(Cr), which is due to a less uniform distribution of Pd nanoparticles in Pd 70Ni 30/MIL-101-NH 2(Cr) originated from amorphization of MIL-101-NH 2(Cr) structure during the reduction process. In contrast, Pd 70Ni 30/MIL-101(Cr) revealed the stable structure and activity during reduction and CO oxidation for a long time. 相似文献
18.
Layered -titanate materials, Na xM x/2Ti 1−x/2O 2 (M=Co, Ni and Fe, x=0.2–0.4), were synthesized by flux reactions, and electrical properties of polycrystalline products were measured at 300–800 °C. After sintering at 1250 °C in Ar, all products show n-type thermoelectric behavior. The values of both d.c. conductivity and Seebeck coefficient of polycrystalline Na 0.4Ni 0.2Ti 0.8O 2 were ca. 7×10 3 S/m and ca. −193 μV/K around 700 °C, respectively. The measured thermal conductivity of layered -titanate materials has lower value than conductive oxide materials. It was ca. 1.5 Wm −1 K −1 at 800 °C. The estimated thermoelectric figure-of-merit, Z, of Na 0.4Ni 0.2Ti 0.8O 2 and Na 0.4Co 0.2Ti 0.8O 2 was about 1.9×10 −4 and 1.2×10 −4 K −1 around 700 °C, respectively. 相似文献
19.
Ln 2B 2O 7 (Ln=Sm, Eu, Gd and Tb; B=Zr or Ti) with pyrochlore structure was prepared by sol–gel method for the high-temperature catalytic combustion. The crystal structure of Ln 2B 2O 7 was identified by XRD and their surface area was about 4 m 2/g after calcinations at 1200 °C. Catalytic activity of methane combustion was observed for Ln 2Zr 2O 7 series and the best catalyst was Sm 2Zr 2O 7. Its relative reaction rate per unit surface area at 600 °C was 2 cm 3/m 2 min, which was twice higher than that of Mn-substituted Sr hexaaluminate. From surface analysis by XPS, the low binding energy of each Ln element of Ln 2Zr 2O 7 compared to that of Ln 2Ti 2O 7, gave the catalytic activity of methane combustion. 相似文献
20.
The air–solid photocatalytic degradation of organic dye films Acid Blue 9 (AB9) and Reactive Black 5 (RBk5) is studied on Pilkington Activ™ glass. The Activ™ glass comprises of a colorless TiO 2 layer deposited on clear glass. The Activ™ glass is characterized using atomic force microscopy (AFM) and X-ray diffraction (XRD). Using AFM, the TiO 2 average agglomerate particle size is 95 nm, with an apparent TiO 2 thickness of 12 nm. The XRD results indicate the anatase phase of TiO 2, with a calculated crystallite size of 18 nm. Dyes AB9 and RBk5 are deposited in a liquid film and dried on the Activ™ glass to test for photodecolorization in air, using eight UVA blacklight-blue fluorescent lamps with an average UVA irradiance of 1.4 mW/cm2. A novel horizontal coat method is used for dye deposition, minimizing the amount of solution used while forming a fairly uniform dye layer. About 35–75 monolayers of dye are placed on the Activ™ glass, with a covered area of 7–10 cm2. Dye degradation is observed visually and via UV–vis spectroscopy. The kinetics of photodecolorization satisfactorily fit a two-step series reaction model, indicating that the dye degrades to a single colored intermediate compound before reaching its final colorless product(s). Each reaction step follows a simple irreversible first-order reaction rate form. The average k1 is 0.017 and 0.021 min−1 for AB9 and RBk5, respectively, and the corresponding average k2 is 2.0 × 10−3 and 1.5 × 10−3 min−1. Variable light intensity experiments reveal a p = 0.44 ± 0.02 exponent dependency of initial decolorization rate on the UV irradiance. Solar experiments are conducted outdoors with an average temperature, water vapor density, and UVA irradiance of 30.8 °C, 6.4 g water/m3 dry air, and 1.5 mW/cm2, respectively. For AB9, the average solar k1 is 0.041 min−1 and k2 is 5.7 × 10−3 min−1. 相似文献
|