共查询到13条相似文献,搜索用时 46 毫秒
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以硼掺杂碳化硅(B0.1SiC)为载体,采用循环伏安法在B0.1SiC载体上电沉积Pt纳米粒子制备了Pt/B0.1SiC催化剂。利用X射线光电子能谱、X射线衍射、氮气吸附-脱附、扫描电镜及透射电镜等测试方法对催化剂的晶型、表面性质及形貌进行了表征。结果表明,硼原子掺杂进入SiC晶格并取代了Si位点,使B0.1SiC载体的导电性增强;Pt纳米粒子均匀地分布在B0.1SiC载体上,平均粒径为2.7 nm。与相同条件下制备的Pt/SiC催化剂相比,Pt/B0.1SiC具有较大的电化学活性表面积、更高的甲醇催化氧化活性和稳定性。 相似文献
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直接甲醇燃料电池(DMFC)由于具有较多的优点而受到广泛的关注. 但是碳载Pt (Pt/C)阳极催化剂电催化活性低是限制其应用的一个主要问题. 为了提高Pt/C催化剂对甲醇氧化的电催化性能, 分别用CO2, 空气, H2O2或HNO3对常用作为载体的Vulcan XC-72碳黑进行预处理. 结果表明, 在用CO2, 空气, HNO3, H2O2处理的及未处理的碳黑作载体制得的Pt/C催化剂电极上, 甲醇氧化峰的峰电流密度顺序为39, 33, 32, 20和18 mA•cm-2, 表明用CO2处理的碳载体制备的Pt/C催化剂对甲醇氧化有最好的电催化活性和稳定性. 其主要原因是用CO2处理能减少碳黑表面的含氧基团和增加石墨化程度, 而使碳黑的电阻降低及Pt粒子在碳黑上的分散性变好. 相似文献
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本文分别用混酸水热法(HT)和混酸冷凝回流法(RF)对Vulcan XC-72R碳黑进行预处理,并进一步研究其作为Pt/C催化剂载体的性能。循环伏安实验发现,采用HT法、RF法和未预处理的碳黑作为载体的Pt/C催化剂电催化甲醇氧化的比质量活性(正扫峰电流)分别为1055、704和395 mA/mgpt,即采用HT法预处理碳载体的Pt/C催化剂具有最高的电催化活性,而且计时电流实验也表现出最好的稳定性。实验结果表明,碳载体的预处理方法对制得的Pt/C催化剂的性能具有关键性的影响,且水热法是一种效果较好的预处理碳载体的方法。 相似文献
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将CeO2溶胶与Pt/C催化剂机械混合制备了Pt-CeO2/C催化剂,研究了酸性条件下Pt-CeO2/C催化剂对甲醇氧化的电催化活性。结果表明,与Pt/C催化剂相比,Pt-CeO2/C催化剂对甲醇展现出更好的催化活性。XRD和TEM测试结果表明,Pt-CeO2/C催化剂中Pt与CeO2的平均粒径均为3~4 nm。对CeO2含量不同的Pt-CeO2/C催化剂在CH3OH-H2SO4中进行循环伏安测试发现,Pt-CeO2/C催化剂对甲醇氧化的电催化活性较高,其中Pt与CeO2质量比为1∶1时,催化剂的催化活性最高,对甲醇氧化的峰电流密度达到0.112 A/cm2。 相似文献
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以Ni (Ac)2·4H2O和生物质材料丝瓜络为原料,通过先浸渍后热解的方法制备了低成本的镍纳米颗粒/丝瓜络衍生氮掺杂多孔碳纳米复合材料(Ni/T-dNPCN)。研究复合材料对甲醇的电催化性能,并讨论热解温度对复合材料结构和性能的影响。结果表明,Ni/T-dNPCN修饰玻碳电极(GCE)在碱性条件下对甲醇氧化反应(MOR)具有良好的电催化活性。其中,800℃煅烧得到的Ni/T-dNPCN800/GCE对1 mol·L-1甲醇具有最低的起始电位(0.344 V (vs Ag/AgCl))、最高的催化电流密度(质量活性:1 902 mA·mgNi-1;比活性:1.61 mA·cm-2)和最快的动力学反应过程(Tafel斜率:50.23 mV·dec-1),其催化活性约为商业化Pt/C/GCE的3.92倍。且计时电流测试表明,Ni/T-dNPCN800/GCE具有良好的稳定性。 相似文献
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Pt微粒修饰纳米纤维聚苯胺电极对甲醇氧化电催化 总被引:9,自引:0,他引:9
以脉冲电流法制备的纳米纤维状聚苯胺(PANI)为Pt催化剂载体,用它制备了甲醇阳极氧化的催化电极Pt/(nano-fibular PANI).研究结果表明, Pt/(nano-fibular PANI)电极对甲醇氧化具有很好的电催化活性,并有协同催化作用.在相同的Pt载量条件下, Pt/(nano-fibular PANI)电极比Pt微粒修饰的颗粒状聚苯胺电极Pt/(granular PANI)具有更好的电催化活性.此外, Pt的电沉积修饰方法同样影响Pt/(nano-fibular PANI)电极对甲醇氧化的催化活性.脉冲电流法沉积Pt形成的复合电极较循环伏安法电沉积得到的Pt复合电极具有更优异的催化活性. 相似文献
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Three-dimensionally (3D) ordered mesoporous carbon sphere arrays (OMCS) are explored to support high loading (60 wt%) Pt nanoparticles as electrocatalysts for the methanol oxidation reaction (MOR). The OMCS has a unique hierarchical nanostructure with ordered large mesopores and macropores that can facilitate high dispersion of the Pt nanoparticles and fast mass transport during the reactions. The prepared Pt/OMCS exhibits uniformly dispersed Pt nanoparticles with an average size of 2.0 nm on the mesoporous walls of the carbon spheres. The Pt/OMCS catalyst shows significantly enhanced specific electrochemically active surface area (ECSA) (73.5 m2 g-1) and electrocatalytic activity (0.69 mA cm-2) for the MOR compared with the commercial 60 wt% Pt/C catalyst. 相似文献
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Isolated polyfluorobenzene (PFB) molecules and their protonated forms are investigated by the AM1 method with full geometry optimization. The proton affinities of PFB are estimated for different protonated positions. The proton affinity of PFB averaged over all isomers is shown to decrease monotonically as the number of fluorine atoms in the molecule increases. The relative populations of different isomers of arenonium ions (AI) formed by PFB protonation are determined. From the calculated data, the value of + for the F atom in theipso-position is estimated as 1.00. The activation energies of the 1,2-hydrogen shifts in AI are calculated. The dependences of the proton affinity and the activation energies of 1,2-hydrogen shifts on the number of halogen atoms are found to have distinct characters for PFB and polychlorobenzenes. The physical reasons for these difference are discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1878–1882, November, 1993. 相似文献
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C. Herrero-Latorre J. Álvarez-MéndezAuthor VitaeJ. Barciela-GarcíaAuthor Vitae S. García-MartínAuthor VitaeR.M. Peña-CrecenteAuthor Vitae 《Analytica chimica acta》2015
In the present paper, a critical overview of the most commonly used techniques for the characterization and the determination of carbon nanotubes (CNTs) is given on the basis of 170 references (2000–2014). The analytical techniques used for CNT characterization (including microscopic and diffraction, spectroscopic, thermal and separation techniques) are classified, described, and illustrated with applied examples. Furthermore, the performance of sampling procedures as well as the available methods for the determination of CNTs in real biological and environmental samples are reviewed and discussed according to their analytical characteristics. In addition, future trends and perspectives in this field of work are critically presented. 相似文献