低镍/ZnO-TiO2催化剂的乙醇水蒸气重整制氢

为考察低镍负载量对乙醇水蒸气重整制氢催化剂性能的影响,利用沉积-沉淀法(DP)制备了镍负载最质量分率为0.5%～5.0%的Ni/ZnO-TiO2催化剂,并在内径14 mm的固定床管式反应器中对低镍催化剂进行了性能评价.结果表明,低镍/ZnO-TiO2催化剂具有较好的乙醇水蒸气重整制氢性能.在水醇物质的量比为13:1及反...     

Ni/ZnO-ZrO2催化低温乙醇水蒸气重整制氢

以草酸钠为共沉淀剂,采用共沉淀法制备了以ZnO-ZrO2为载体的镍基乙醇水蒸气重整制氢催化剂(Ni/ZnO-ZrO2)。考察了不同锌锆摩尔比的ZnO-ZrO2负载的镍基催化剂在300～450℃催化乙醇水蒸气重整制氢的反应性能。用TPR、TPO、XRD对催化剂试样进行了表征。结果表明,当n(Zn)∶n(Zr)=1∶1,Ni负载质量分数10%时,催化剂中有镍锌复合氧化物生成,350℃时乙醇转化率达100%,450℃氢气选择性接近90%;TPO结果表明,ZnO-ZrO2复合载体可以降低催化剂上的积炭量。     

Hydrogen Production from Ethanol Steam Reforming Over Supported Cobalt Catalysts

Hydrogen production was carried out via ethanol steam reforming over supported cobalt catalysts. Wet incipient impregnation method was used to support cobalt on ZrO₂, CeO₂ and CeZrO₄ followed by pre-reduction with H₂ up to 677 °C to attain supported cobalt catalysts. It was found that the non-noble metal based 10 wt.% Co/CeZrO₄ is an efficient catalyst to achieve ethanol conversion of 100% and hydrogen yield of 82% (4.9 mol H₂/mol ethanol) at 450 °C, which is superior to 0.5 wt.% Rh/Al₂O₃. The pre-reduction process is required to activate supported cobalt catalysts for high H₂ yield of ethanol steam reforming. In addition, support effect is found significant for cobalt during ethanol steam reforming. 10% Co/CeO₂ gave high H₂ selectivity while suffered low conversion due to the poor thermal stability. In contrast to CeO₂, 10 wt.% Co/ZrO₂ achieved high conversion while suffered lower H₂ yield due to the production of methane. The synergistic effect of ZrO₂ and CeO₂ to promote high ethanol conversion while suppress methanation was observed when CeZrO₄ was used as a support for cobalt. This synergistic effect of CeZrO₄ support leads to a high hydrogen yield at low temperature for 10 wt.% Co/CeZrO₄ catalyst. Under the high weight hourly space velocity (WHSV) of ethanol (2.5 h⁻¹), the hydrogen yield over 10 wt.% Co/CeZrO₄ was found to gradually decrease to 70% of its initial value in 6 h possibly due to the coke formation on the catalyst.     

Cu-Ni/Al_20_3-SiO_2催化剂上乙醇水蒸气重整制氢

采用共沉淀法、热分解和氢还原等步骤制备了纳米晶载体催化剂Cu-Ni/Al203-SiO2,应用X射线衍射、x射线光电子能谱、扫描电镜对催化剂的体相和表面结构进行了测定,采用固定床反应器考察了催化剂对乙醇水蒸气重整制氢反应的催化性能。实验结果表明,5%Cu-Ni/Al203-SiO2催化剂对乙醇的低温水蒸气重整反应表现出较高的催化活性,350℃时乙醇的转化率已达到100%。在650℃时氢气的选择性可达78.5%。增加铜含量对增加催化剂的活性没有帮助。     

Cu-Ni/Al2O3-SiO2催化剂上乙醇水蒸气重整制氢

采用共沉淀法、热分解和氢还原等步骤制备了纳米晶载体催化剂Cu-Ni/Al2O3-SiO2,应用X射线衍射、x射线光电子能谱、扫描电镜对催化剂的体相和表面结构进行了测定,采用固定床反应器考察了催化剂对乙醇水蒸气重整制氢反应的催化性能。实验结果表明,5%Cu-Ni/Al2O3-SiO2催化剂对乙醇的低温水蒸气重整反应表现出较高的催化活性,350℃时乙醇的转化率已达到100%。在650℃时氢气的选择性可达78.5%。增加铜含量对增加催化剂的活性没有帮助。     

Stable Hydrogen Production from Ethanol through Steam Reforming Reaction over Nickel-Containing Smectite-Derived Catalyst

Hydrogen production through steam reforming of ethanol was investigated with conventional supported nickel catalysts and a Ni-containing smectite-derived catalyst. The former is initially active, but significant catalyst deactivation occurs during the reaction due to carbon deposition. Side reactions of the decomposition of CO and CH₄ are the main reason for the catalyst deactivation, and these reactions can relatively be suppressed by the use of the Ni-containing smectite. The Ni-containing smectite-derived catalyst contains, after H₂ reduction, stable and active Ni nanocrystallites, and as a result, it shows a stable and high catalytic performance for the steam reforming of ethanol, producing H₂.     

Hydrogen Production for Fuel Cells from the Catalytic Ethanol Steam Reforming

Alumina-supported rhodium catalysts were shown to be active, selective and stable catalysts in the catalytic ethanol steam reforming when the reaction is carried out under pressure (1.1 MPa). Both the nature of the metal precursor salt, the metal loading and the reaction conditions were shown to influence the activity, the selectivity and the stability of the catalysts. Some trends observed when the reaction is carried out under moderate pressure were shown to be different from the conclusions drawn from earlier results obtained at atmospheric pressure. In fact, rhodium catalysts derived from a chlorinated metal precursor were shown to be the most active, selective and stable.     

复合载体Ni催化剂乙醇水蒸气重整制氢研究

用沉积-沉淀法制备了以ZnO为主要组分的多种复合载体（ZnO-Al2O3、ZnO-TiO2、ZnO-MgO、ZnO-CeO2、ZnO-ZrO2）Ni基催化剂,在固定床反应器上考查了催化剂的乙醇水蒸气重整制氢反应性能。结果表明,催化剂复合载体组分对乙醇水蒸气重整制氢性能有影响,其中,在较低温度（400～470℃）Ni/ZnO催化剂的催化性能最优,而在较高温度（485～550℃）Ni/ZnO-TiO2催化剂有相对最优的催化性能。催化剂的XRD、SEM等表征表明,Ni催化剂活性组分分散良好,催化剂颗粒大小较为均匀,同时也观察到使用后的催化剂表面有积炭生成。     

金属／MgO上的乙醇水蒸气重整制氢

研究了氧化镁负载镍、铁、钴、锰、钼、铜和锡等金属催化剂在乙醇水蒸气重整反应的性能,结果表明在650℃,101．3kpa条件下,所有催化剂的活性都较高,乙醇接近完全转化,而对氢的选择性顺序为：Ni〉Co〉Sn〉Cu〉Fe〉Mo〉Mn。除镍的选择性是随温度上升之外,其他催化剂的选择性都随温度变化有个最佳值。镍催化剂的TPR和XRD表征表明,催化剂中存在3种形态的镍。     

Ni-Cu/蒙脱土乙醇水蒸气重整制氢催化剂性能研究

生物乙醇重整制氢是一种具有良好应用前景的制氢技术,是当前低碳能源领域的研究热点.本文采用离子交换法制备了Ni-Cu/蒙脱土双金属催化剂,并将其应用于乙醇水蒸气重整制氢.采用X射线衍射(XRD)、比表面积测定(BET)、H2-程序升温还原(H2-TPR)和透射电子显微镜(TEM)等表征手段对催化剂的物相结构、织构性质、还原性能、微观形貌等进行了研究.结果表明:Ni、Cu均为乙醇水蒸气重整制氢的活性组分,铜的加入可以减少镍颗粒的尺寸、优化镍组分的分布状态.此外,Ni-Cu双金属催化剂的双功能特性使其优于单一金属催化剂.Ni-Cu/蒙脱土在焙烧温度500℃、水醇比为8∶1、空速为80000 mL/gcat·h,反应进行10 h后,仍保持72.09％的氢气的选择性,说明Ni-Cu/蒙脱土双金属催化剂在乙醇水蒸气重整制氢中具有良好的催化活性和稳定性.     

烃类蒸汽转化催化剂表面改性的研究

本文介绍了烃类蒸汽转化催化剂表面改性的试验, 经表面改性后, 在不降低催化剂原有低温还原性及强度等性能的基础上, 其样品的初活性及活性稳定性明显提高, 试验达到了预期的目的。     

On the Catalytic Activity of Cobalt Oxide for the Steam Reforming of Ethanol

The paper presents an investigation on the catalytic activity for the ethanol steam reforming of Co₃O₄ oxidized, reduced and supported on MgO, and of CoO in MgO solid solution. Only samples containing metallic cobalt are found to be active for reforming reaction. H₂-TPR characterization of aged samples shows that reaction mixture oxidizes a small fraction of metallic cobalt to Co⁺². A distinct role of Co⁺² and Co⁰ in the reaction is enlightened.     

Low Temperature and H2 Selective Catalysts for Ethanol Steam Reforming

Supported Rh catalysts have been developed for selective H₂ production at low temperatures. Ethanol dehydration is favorable over either acidic or basic supports such as γ-Al₂O₃ and MgAl₂O₄, while ethanol dehydrogenation is more favorable over neutral supports. CeO₂–ZrO₂-supported Rh catalysts were found to be especially effective for hydrogen production. We focused on a support prepared by a co-precipitation method having composition Ce_0.8Zr_0.2O₂. A 2%Rh/Ce_0.8Zr_0.2O₂ catalyst, prepared via impregnation without pre-calcination of support, exhibited the highest H₂ yield at 450 °C among various supported Rh catalysts evaluated in this study. This may be due to both the strong interaction between Rh and Ce_0.8Zr_0.2O₂ and the high oxygen transfer rate favoring reforming of acetaldehyde instead of methane production.     

用于燃料电池的甲醇水蒸气重整反应制氢的研究

研究了甲醇水蒸气重整制氢反应过程中各种因素对Cu/ZnO/Al2O3催化剂的活性和选择性的影响.结果表明:Cu/Zn比为2.0的催化剂在250℃反应时,催化剂效果较好,最合适反应条件是:压力0.1 MPa,温度250℃,n(H2O)∶n(CH3OH)=1.0～1.2,液体流速0.1 mL/min.在Cu/ZnO/Al2O3催化剂上,甲醇水蒸气重整、甲醇分解和水气转换反应随反应条件的不同而发生相互抑制或促进作用.     

甲醇水蒸气重整制氢研究进展

介绍了国内外甲醇-水蒸气重整制氧的研究进展,包括反应机理,热力学、动力学模型,以及催化剂的制备情况,并对其未来发展作了展望.     

甲醇水蒸汽重整制氢Au/TiO2催化剂

采用沉积-沉淀法制备了一系列Au/TiO2催化剂,考察了Au负载量、焙烧温度以及助剂等因素对甲醇水蒸汽重整制氢反应催化性能的影响;并利用XRD, TEM对催化剂进行了表征. 结果表明,制备条件对催化性能有明显影响;Au负载量为5%(w)时所得催化剂活性较好;助剂NiO可使催化剂催化甲醇水重整的催化活性明显提高;100℃烘干未焙烧制得的催化剂活性最好;TEM结果显示,NiO的加入使载体TiO2颗粒分散度提高,Au粒粒度变小.     

甲醇蒸汽重整制氢技术及经济性探讨

介绍甲醇蒸汽重整制氢工艺和催化剂,对甲醇蒸汽重整制氢气技术的生产成本进行分析评价,还介绍甲醇蒸汽重整制氢技术在燃料电池中的应用.     

甲醇蒸汽重整制氢技术及经济性探讨

介绍甲醇蒸汽重整制氢工艺和催化剂,对甲醇蒸汽重整制氢气技术的生产成本进行分析评价,还介绍甲醇蒸汽重整制氢技术在燃料电池中的应用。     

铜促进型烃类蒸汽转化催化剂性能研究

采用常压-微反色谱装置(MRC)、TPR、ATGA等技术，对铜促进型烃类蒸汽转化催化剂的活性、还原性和抗结矿能进行了研究。Cu的引入可显著降低NiO／α-Al2O3催化剂上NiO的还原温度，随着Cu含量的增加，这种作用愈加明显。当Cu的加入量很低时，能提高催化剂活性，当含量超过一定范围后，活性则迅速下降。Cu对催化剂抗结碳性能的影响出现极值。加入微量或大量Cu都可降低结碳速率。兼顾Cu对还原性、活性和抗结碳性的影响以及转化反应对催化剂的要求。CuO的加入量应在NiO含量的1％以下。     

Reactivity of Aluminum Spinels in the Ethanol Steam Reforming Reaction

Aluminum spinels, MAl₂O₄ with M²⁺ = Cu, Zn or Ni, were prepared by citrate method and its reactivity in the ethanol steam reforming reaction was studied at 500 °C. They were characterized by TG, BET surface area, XRD, FTIR and TPR techniques. The catalytic behavior depended strongly on the nature of divalent metal which determines the physico-chemical properties of samples. In all cases, very active catalysts with a complete ethanol conversion were reached. Hydrogen yield follows the order of ZnAl > NiAl > CuAl.