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研制了葡萄糖催化氧化的多元金属催化剂，结果表明：助催化剂的加入不但提高了催化剂的催化活性，而且降低了活性组分（贵金属）含量，降低了催化剂成本。 相似文献
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贵金属催化剂通常被认为是氧还原反应和氧析出反应缓慢的四电子转移机理的最佳电催化剂.但由于其成本高,资源稀少且稳定性不足,使大规模的商业化受到了限制.因此,在同等催化性能的条件下,低成本且环境友好的非贵金属电催化剂将成为未来电催化剂工程的重点.以二氰二胺为碳源,利用基团配位作用结合冷冻干燥策略,经过碳化处理制备CoV碳纳米管复合材料(命名为CoV-NC).通过扫描电镜、X-射线衍射光谱、N2吸附—脱附曲线等对样品进行形貌和结构表征.在0.1 M KOH电解液中,CoV-NC催化剂的ORR起始电位为0.931V,并具有较高的极限电流密度.在电流密度为10 mA·cm-2时,OER电压仅为1.63 V,证明CoV-NC具有较好的ORR和OER催化活性.作为空气—正极材料组装成的一次锌-空电池,在5 mA·cm-2电流密度下可连续放电166 h,性能优于商业Pt/C催化剂. 相似文献
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采用六水硝酸铈和氢氧化钠为反应物,用水熟合成法制备了纳米Ce02.并以不同合成条件下得到的CeO2为栽体,担载了相同含量的贵金属Au,制备了具有高活性的Au/CeO2催化荆.实验结果发现,以CeO1-2h为载体的催化剂在高温区易展现出较好的活性,而以CeO2-10h为载体的催化剂在低温区易展现出较好的活性.说明载体结构对催化荆的CO催化氧化活性有决定性的作用. 相似文献
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我国具有丰富的稀土资源,利用稀土制造的新型材料,已广泛应用到许多领域.近几年来,稀土在催化研究方面已取得了新的进展,如稀土在纳米材料、石油裂化、合成橡胶、催化燃烧、车用催化剂中都有重要的应用,并且其应用前景日益广阔. 相似文献
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综述了邻、对氯硝基苯还原制备邻、对氯苯胺的七类方法,对各类方法进行了对比和讨论,其中环境友好的催化加氢还原法可通过添加脱氯抑制剂和改善催化剂性能两条途径来提高反应的选择性。认为氯代硝基苯液相催化加氢法是制备氯代苯胺的首选方法,可采用廉价的镍基催化剂替代贵金属类催化剂,其中脱氯问题的解决是Ni基催化剂大规模应用于氯代苯胺合成工艺过程的关键。 相似文献
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贵金属纳米粒子因其特有的光学以及化学和催化性能,正引起科技界越来越浓厚的兴趣.通常这些特性决定于这些金属粒子的粒径和形态.由于非球形粒子比各向同性的球形粒子具有更优越的性能,它们已经成为研究的焦点,人们正在努力寻找粒子形状如何影响粒子理化性能的答案.贵金属纳米粒子的形状可控合成技术已经取得了明显进展.本文就贵金属纳米粒子的形状可控合成及其应用研究的当前进展进行综合评述. 相似文献
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采用不同方法合成了一系列的贵金属Pt单金属及多金属催化剂．研究了它们对甘油选择性催化氧化反应的催化性质．催化荆9％Pt-5％Bi／C可以有效地将甘油选择性催化氧化成二羟基丙酮，当反应温度为55℃，反应时间为50h时，甘油全部转化，二羟基丙酮的产率为50．05％． 相似文献
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催化剂种类对PECVD制备碳纳米管的影响 总被引：1，自引：1，他引：0
席彩萍 《渭南师范学院学报》2011,(12):46-49
采用PEVCD技术,分别用Fe、Ni、Co作为催化剂,在Si基底上沉积出了不同形貌的碳纳米管．并用扫描电镜对碳纳米管的形貌进行了表征．而且深入研究了不同催化剂种类对碳纳米管生长的影响机理．结果表明：Ni是这3种催化剂中最适合沉积碳纳米管的催化剂． 相似文献
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催化裂化装置催化剂磁分离技术是从废催化剂中分离出重金属含量低、活性和选择性好的低磁催化剂再利用。该技术可以优化催化过程,改善产品分布,提高轻质油等高附加值产品的收率,同时又可降低生产成本,减少催化剂对环境的污染。由于低磁剂的微反活性、比表面积、重金属含量等较处理前大幅改善,使用后系统催化剂性能明显好转,能显著提高装置轻油收率,并降低催化剂单耗,经济效益也十分明显。催化剂磁分离技术具有工艺简单、投资小、能耗少、过程不使用任何化学品、无环境污染、经济效益显著等优点,具有广阔的应用前景。 相似文献
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为获得高效催化还原对硝基苯酚的锰钴氧化物催化剂,以聚甲基丙烯酸甲酯为模板,采用硬模板法制备了具有三维有序大孔结构的尖晶石型锰钴氧化物(MnCo2O4)。运用X射线粉末衍射仪、全自动物理吸附仪、扫描电子显微镜及紫外-可见分光光度计等对催化剂的结构和形貌进行表征,并研究其对硼氢化钠还原对硝基苯酚反应的催化性能。结果表明,多孔MnCo2O4催化剂具有立方晶相结构,其三维有序大孔孔径均一,比表面积达到65.7 m2/g;与体相MnCo2O4和其他贵金属催化剂相比,多孔MnCo2O4催化剂表现出更优异的催化活性,对硝基苯酚还原的反应速率常数可达6.59×10-2s-1。多孔MnCo2O4催化剂在5次重复利用后对硝基苯酚的转化率仍高达90%以上。 相似文献
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为研究铂负载型催化剂时甲醛催化氧化反应的活性,采用溶胶一凝胶法制备了不同载体的铂负载型催化剂,并对催化剂进行XRD、Raman等表征,考察所制催化剂对甲醛催化氧化反应性能。结果表明：载体的性质在反应中起到重要作用,惰性载体无法促进氧的活化,其催化活性较低;对比不同比表面积的Pt／CeO2催化剂,发现比表面积为38mVg的催化剂的催化氧化性能最佳,这与催化剂的氧缺位浓度较高及较强的金属一载体间相互作用有关。 相似文献
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考察了稀土氧化物负载CuO催化剂的CO氧化活性和还原性能,发现CuO／CeO2催化剂具有很高的CO氧化活性,65℃时,CO转化率可达95％． 相似文献
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Diesel emission fluid (DEF) soaking and urea deposits on selective catalytic reduction (SCR) catalysts are critical issues for real diesel engine NH3-SCR systems. To investigate the impact of DEF soaking and urea deposits on SCR catalyst performance, fresh Cu-zeolite catalyst samples were drilled from a full-size SCR catalyst. Those samples were impregnated with DEF solutions and subsequently hydrothermally treated to simulate DEF soaking and urea deposits on real SCR catalysts during diesel engine operations. Their SCR performance was then evaluated in a flow reactor with a four-step test protocol. Test results show that the DEF soaking leached some Cu from the SCR catalysts and slightly reduced their Cu loadings. The loss of Cu and associated metal sites on the catalysts weakened their catalytic oxidation abilities and caused lower NO/NH3 oxidation and lower high-temperature N2O selectivity. Lower Cu loading also made the catalysts less active to the decomposition of surface ammonium nitrates and decreased low-temperature N2O selectivity. Cu loss during DEF impregnation released more acid sites on the surface of the catalysts and increased their acidities, and more NH3 was able to be adsorbed and involved in SCR reactions at medium and high temperatures. Due to lower NH3 oxidation and higher NH3 storage, the DEF-impregnated SCR catalyst samples showed higher NO x conversion above 400 °C compared with the non-soaked one. The negative impact of urea deposits during DEF impregnation was not clearly observed, because the high-temperature hydrothermal treatment helped to remove the urea deposits. 相似文献
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In this study, a series of novel Pt-Ni bimetallic catalysts supported on LaFeO_3/SiO_2 with different amounts of Ni were prepared by the lattice atomic-confined reduction of LaFe_(1-x)(Ni, Pt)_xO_3/SiO_2 perovskite precursors and applied in isobutane dehydrogenation to isobutene reaction. The catalysts were characterized by X-ray diffraction, H_2-temperature-programmed reduction, Brunauer-Emmett-Teller analysis, transmission electron microscopy, energy dispersive X-ray, CO chemisorption, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The as-synthesized Pt-Ni bimetallic catalysts possessed smaller most probable particle size with tunable Pt-Ni interaction, depending on the Ni content. The catalyst with Ni content of 3.0 wt% showed excellent activity and stability(the isobutane conversion and isobutene selectivity remained at about 38% and 92%, respectively, after 310 min) for the isobutane dehydrogenation reaction. It also provided approximately six times turnover frequency of the catalyst without Ni. The excellent activity and stability of the 3.0 wt% Ni-containing catalyst can be attributed to its small metal nanoparticles with high dispersion and suitable Pt-Ni interaction. Moreover, the Pt(Ni)-LaFeO_3/SiO_2 catalyst with Ni content of 3.0 wt% had been run for more than 35 h without obvious loss of activity,indicating its long-term stability, and the decrease in the Pt-Ni interaction that accompanied the formation of the FeNi alloy phase was thought to be responsible for the slight decrease in activity. 相似文献