共查询到19条相似文献,搜索用时 62 毫秒
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用化学还原法制备了碳载镍、银、金三种金属单质催化剂,并研究其对甲醇电催化氧化的活性。用X射线衍射光谱(XRD)、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。XRD测试表明均得到了纯度较高的金属单质,催化剂粒径大小在5 nm-11nm之间,颗粒分布均匀。用循环伏安法测定了不同催化剂对甲醇的电催化氧化的活性,结果表明碳载镍催化剂对甲醇氧化有较好的催化作用,而碳载银和碳载金对甲醇氧化几乎没有活性。 相似文献
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直接甲醇燃料电池阳极非铂催化剂的研究进展 总被引:1,自引:0,他引:1
介绍了直接甲醇燃料电池(DMFC)的特点及其阳极催化剂存在的主要问题。综述了DMFC阳极非铂催化剂的研究进展及非铂催化剂对甲醇氧化的催化活性和抗CO等中间物毒化能力等性能,提出了DMFC阳极非铂催化剂存在的问题以及发展趋势。 相似文献
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采用了热分解法合成Ni-Cr-Co氧化物纳米粒子,并用作直接甲醇燃料电池(DMFC)的阳极电催化剂。通过X射线衍射(XRD)、透射电子显微镜(TEM)和扫描电子显微镜(SEM)对催化剂进行表征,制得的纳米催化剂均匀分散,且粒径为25~50 nm。利用循环伏安法(CV)对不同金属摩尔比和焙烧温度下的催化剂在甲醇氧化反应中的活性进行了研究。结果表明,Ni-Cr-Co(摩尔比为1∶1∶1.5)的纳米氧化物对甲醇氧化反应的起始电位、峰值氧化电流密度和If/Ib分别为0.38 V,19.3 mA/cm2和1.72,表现了很好的电催化性能。 相似文献
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阳极催化剂是影响直接甲醇燃料电池(DMFC)性能及成本的主要因素之一,从催化剂载体选择、复合催化剂的制备、非贵金属催化剂研究三方面综述了DMFC阳极催化剂国内外研究现状,并进行了简要分析,展望了其应用前景。 相似文献
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本文叙述了反应条件对合成甲醇铜基催化剂活性(时空收率和 CO 转化率)的影响.时空收率和 CO 转化率均随反应压力的升高而增加;在一定空速范围内,时空收率随空速增大而增加,而CO 转化率随空速的增大而降低;反应温度为250℃时,时空收率和 CO 转化率均达最高值. 相似文献
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Copper-zinc catalysts deposited by impregnation on different oxidised carbon supports (activated carbon, black carbon and carbon fibres) were tested in the partial oxidation of methanol (POM) (CH3OH + 1/2 O2 2 H2 + CO2). Characterisation of the samples by N2 adsorption, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) revealed differences in the dispersion, location and relative distribution of the active phase on the surface of the carbonaceous supports. These properties have important implications in the catalytic behaviour of the samples in the POM reaction. The location of active phases on the microporous structure implies lower initial activities and better thermal stability. These results may be due to limitations in the access of the reagents to the active phase and the prevention of copper-sintering effects. 相似文献
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用PVP保护乙醇还原法制备了一系列Au-Pd/MOx(M=Zn、Ce、Fe、Ti、Cr和Al)双金属催化剂,考察了不同载体对Au-Pd催化剂甲醇部分氧化制氢性能的影响,用XRD、TG、TPD、TPR和TPH等对催化剂进行了表征。结果表明,载体对催化剂性能有较大影响,与钛、铬和铝氧化物载体相比,448K时偏碱性的锌、铈和铁氧化物载体负载的Au-Pd催化剂的甲醇转化率均在80.0%以上,催化剂积碳量降低。其中以Au-Pd/ZnO催化剂的效果最好,523K时甲醇转化率和氢气选择性分别为99.0%和45.6%,反应20h后积碳量仅为0.0232g/gcat.。 相似文献
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B. Ramachandra Jung Sik Choi Ko-Yeon Choo Jae-Suk Sung Sun-Dal Song Tae-Hwan Kim 《Catalysis Letters》2005,105(1-2):23-27
Molybdenum based mixed oxide containing Mo0.65V0.25W0.10 was investigated for the partial oxidation of methanol. The structural property and catalytic activity of the mixed oxide
catalyst was studied by surface area (BET), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), Fourier transform
infra-red spectroscopy (FTIR) and X-ray diffraction (XRD). The thermal activation of the catalyst resulted increase in the
conversion of methanol and the selectivity to formaldehyde. The thermal activation of the MoVW mixed oxide in nitrogen atmospheres
induces partial crystallization of a Mo5O14-type oxide at 813 K. The SEM images of the thermally activated catalyst show needle like particles. These particles were
agglomerates of platelet-like crystallites of a few hundreds of nanometers in size. SEM and EDX techniques show that the mixed
oxide is characterized by an inhomogeneous elemental distribution on the length scale of a few microns. XRD of the thermally
activated catalyst showed a nanocrystalline material identified as a mixture of Mo5O14, MoO3 and MoO2-type MoVW oxides. The catalytic activity of the MoVW mixed oxide show a good conversion of methanol and selectivity to formaldehyde. 相似文献
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合成催化剂装填、升温、还原和使用后,随着其活性和选择性的下降,要进行更换,本文主要介绍了甲醇合成催剂的钝化,选择合理的工艺钝化方案和钝化的过程,并进行了总结。 相似文献
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合成甲醇催化剂的研究进展 总被引:1,自引:0,他引:1
介绍了国内外合成甲醇催化剂的研究情况;从性能参数、测定数据、制备方法等方面阐述了锌铬催化剂、铜基催化剂、合金催化剂等国外新型金属催化剂的研究进展。 相似文献
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介绍了LC210型联醇催化剂和LC308型合成甲醇催化剂的特点和性能,分析了工艺条件对催化剂性能的影响,对技术经济指标和经济效益进行了总结。 相似文献
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A.J. Dickinson L.P.L. Carrette J.A. Collins K.A. Friedrich U. Stimming 《Journal of Applied Electrochemistry》2004,34(10):975-980
This paper describes the effects of varying the Pt to Ru ratio in carbon-supported catalysts for methanol oxidation as a function of temperature. Previously these effects were studied in isolation, but now it is shown that the composition of a given catalyst as a function of temperature is extremely important for its activity towards methanol oxidation. Platinum rich 3:2 atomic ratio catalysts perform better than a 1:1 catalyst at 25 °C, where only Pt is believed to be active towards methanol dehydrogenation, since this process is a highly thermally activated process on Ru sites. This result is reversed at 65 °C, where the 1:1 catalyst displays much higher currents across the entire range of polarization. This may result from methanol dehydrogenation occurring on both Ru and Pt sites at higher temperatures. At an intermediate temperature, 45 °C, the 3:2 catalyst is seen to perform better at lower current values, while the 1:1 catalyst is superior at higher current densities, with the crossover occurring at 62 A g–1. As a consequence, when designing fuel cell catalysts, the composition of the catalyst employed should be tailored with respect to the exact operating conditions, in order to promote optimum fuel cell performance. 相似文献