Ni/MgO-CeO2催化低温乙醇水蒸气重整制氢

采用固相燃烧法制备了MgO,CeO2载体和不同摩尔比的Mgo-CeO2复合载体,采用浸渍法制备了Ni/MgO,Ni/CeO2,Ni/Mgo-CeO2系列催化剂,考察了各催化剂催化乙醇水蒸气重整反应的性能.用BET技术测定了载体的比表面,并用X射线衍射(XRD)、程序升温还原(TPR)和热重(TG)技术对催化剂进行表征.结果表明,在Ni/CeO2和Ni/Mgo-CeO2上,Ni以高分散的NiO、体相NiO和与载体发生相互作用的NiO的形式存在,显示了良好的低温乙醇水蒸气重整性能;其中Mg,Ce摩尔比为1:1时,Ni/MgO-CeO2催化剂显示了良好的活性和选择性,并且具有很好的稳定性和抗积炭能力.     

Ir/CeO2催化剂上乙醇水蒸气重整反应的研究

研究了Ir/CeO2催化剂在乙醇水蒸气重整反应中的催化性能.用沉积沉淀法在高比表面的CeO2载体上制备了Ir/CeO2催化剂,采用X射线衍射光谱、程序升温还原和透射电子显微镜对催化剂的晶相组成、还原性能和形貌进行了表征.结果表明,Ir和CeO2之间发生了强烈的相互作用,从而明显改善了Ir粒子的分散.Ir具有优异的C-C键断裂性能,在低温下即可实现乙醇的完全转化,而在高温区具有很好的甲烷重整性能,可获得很高的氢气产率.     

镍基催化剂上乙醇水蒸气重整反应的研究

考察了载体对Ni催化剂乙醇水蒸气重整制氢反应性能的影响。结果表明，Ni/CeO2催化剂具有较好的低温活性和氢气选择性。对Ni担载量和焙烧温度考察发现，400℃焙烧的15%NiCeO2催化剂具有较好的催化性能；继续升高焙烧温度引起NiO和CeO2粒子的显著增大,导致对氢气选择性的降低。较小的Ni和CeO2粒子有利于乙醇水汽重整反应的进行，而大的粒子倾向于乙醇的分解反应。 350℃时,在反应过程中分别添加CO、CO2和CH4的结果表明没有发生CO和CO2甲烷化反应,而发生了一定程度的CH4水汽重整反应。     

花状微球NiO/CeO_2催化剂上乙醇水蒸气重整制氢研究

用水热法制备微米尺寸CeO2花状微球粉体,并通过浸渍/热分解法在该粉体上担载纳米尺寸的NiO颗粒,制得催化剂NiO/CeO2。对催化剂进行了XRD、SEM、XES和BET物性表征。经固定床反应器对催化剂的催化性能进行测试。装载1.0 g催化剂,液体处理量0.05 mL/min。结果表明,该方法合成的催化剂NiO/CeO2对低温乙醇水蒸气重整反应表现出较高的活性和稳定性。同时通过微量Cr、Zn、Cu的加入在低温区抑制了CO、CH4的生成,提高了H2的产率和催化剂的抗积炭能力。该催化剂连续稳定性测试达到2 000 h;进行反复起动稳定性测试12次后,未表现出失活特征。     

柠檬酸络合法制备的Co/CeO2催化剂上中温乙醇水蒸气重整性能（英文）

采用柠檬酸络合法制备了Co/CeO2及其钙掺杂系列催化剂,并对催化剂进行了低温N2物理吸附、X射线衍射、H2程序升温还原、傅里叶变换红外光谱、高分辨透射电镜表征以及乙醇水蒸气重整催化性能测试.结果表明,所制Co/CeO2催化剂具有良好的乙醇水蒸气重整催化性能,500oC时乙醇能全部转化为C1,氢气产率高达85%以上.Ca掺杂减小了载体CeO2纳米颗粒尺寸,但对还原后Co0尺寸的影响较小.当Ca掺杂量大于5.0%时,催化剂氧化还原性能和乙醇水蒸气重整催化性能下降.较高的还原温度有利于体相Ce4+还原为Ce3+,并且提高了催化活性,认为金属-氧化物边界的增加提高了催化活性.初步稳定性考察结果表明,5%钙掺杂后的催化剂具有更好的抗积炭性能.     

柠檬酸络合法制备的Co/CeO_2催化剂上中温乙醇水蒸气重整性能(英文)

采用柠檬酸络合法制备了Co/CeO2及其钙掺杂系列催化剂,并对催化剂进行了低温N2物理吸附、X射线衍射、H2程序升温还原、傅里叶变换红外光谱、高分辨透射电镜表征以及乙醇水蒸气重整催化性能测试.结果表明,所制Co/CeO2催化剂具有良好的乙醇水蒸气重整催化性能,500oC时乙醇能全部转化为C1,氢气产率高达85%以上.Ca掺杂减小了载体CeO2纳米颗粒尺寸,但对还原后Co0尺寸的影响较小.当Ca掺杂量大于5.0%时,催化剂氧化还原性能和乙醇水蒸气重整催化性能下降.较高的还原温度有利于体相Ce4+还原为Ce3+,并且提高了催化活性,认为金属-氧化物边界的增加提高了催化活性.初步稳定性考察结果表明,5%钙掺杂后的催化剂具有更好的抗积炭性能.     

制备方法对CuO/CeO_2-ZrO_2催化CO低温氧化活性的影响

采用微波加热分解法(一步法)和微波加热处理共沉淀+浸渍法(两步法)制备了CuO/CeO2-ZrO2催化剂,并对其进行了X射线衍射、低温氮气吸附/脱附和程序升温还原等表征,采用色谱流动法考察了催化剂的催化CO低温氧化性能.结果表明,一步法比两步法更有利于使催化剂表面CuO高度分散,CuO与CeO2-ZrO2间的相互作用更强,CuO更容易被还原,从而具有更高的催化CO氧化活性.与CeO2-ZrO2有相互作用的高分散和小颗粒CuO有利于催化剂活性的提高,与CeO2-ZrO2无相互作用的大颗粒CuO对催化剂的活性有抑制作用.     

La_2O_3对CuO/CeO_2水煤气变换反应催化剂微观结构及催化性能的影响(英文)

以La2O3为助剂,采用共沉淀法制备了具有良好催化活性和热稳定性的CuO/CeO2-La2O3水煤气变换反应催化剂,其中,当La2O3含量为2wt%时,催化剂的催化性能最为优异.同时运用X射线衍射、N2吸附-脱附、Raman光谱、程序升温还原等手段,研究了不同含量的La2O3对CuO/CeO2催化剂微观结构及催化性能的影响.结果表明,La2O3助剂进入了载体CeO2的晶格并对CuO/CeO2催化剂的微观结构和催化性能产生了直接影响,适量La2O3的添加可以抑制CuO和CeO2晶格的长大、增强CuO与CeO2间的相互作用、提高催化剂的比表面积、促进CeO2载体中生成更多的氧空位,CuO/CeO2催化剂的催化活性和热稳定性也明显改善.     

La2O3对CuO/CeO2水煤气变换反应催化剂微观结构及催化性能的影响（英文）

以La2O3为助剂,采用共沉淀法制备了具有良好催化活性和热稳定性的CuO/CeO2-La2O3水煤气变换反应催化剂,其中,当La2O3含量为2wt%时,催化剂的催化性能最为优异.同时运用X射线衍射、N2吸附-脱附、Raman光谱、程序升温还原等手段,研究了不同含量的La2O3对CuO/CeO2催化剂微观结构及催化性能的影响.结果表明,La2O3助剂进入了载体CeO2的晶格并对CuO/CeO2催化剂的微观结构和催化性能产生了直接影响,适量La2O3的添加可以抑制CuO和CeO2晶格的长大、增强CuO与CeO2间的相互作用、提高催化剂的比表面积、促进CeO2载体中生成更多的氧空位,CuO/CeO2催化剂的催化活性和热稳定性也明显改善.     

载体对镍催化剂催化乙醇水蒸气重整制氢反应性能的影响

 采用等量浸渍法制备了不同载体负载的镍催化剂,考察了载体对催化剂催化乙醇水蒸气重整制氢反应性能的影响. 结果表明,在650 ℃和101.3 kPa下,不同载体负载的催化剂上乙醇的转化率都接近100%,但选择性相差很大,选择性大小顺序为: ZnO≈La2O3＞CeO2＞MgO＞γ-Al2O3＞TiO2＞ZrO2＞硅胶＞硅藻土. TPR和XRD结果表明,除TiO2外,各载体负载的催化剂的主要物相中都包括NiO相,其对催化剂的活性起重要作用,而Ni与载体的相互作用程度影响催化剂的选择性. 当相互作用较弱,活性组分基本以NiO相存在时,催化剂的选择性较低;当相互作用太强,不存在NiO相时,催化剂的活性和选择性都很低; 当相互作用较强,部分Ni与载体作用生成新物相且与NiO相共存时,催化剂的活性和选择性最高.     

Cu/ZrO2催化剂上乙醇水蒸气重整反应的研究Ⅰ催化剂性能及其制备参数的影响

研究了Cu/ZrO2催化剂在乙醇水蒸气重整反应中的催化性能。用常规沉淀法、醇凝胶法制备了ZrO2载体;用浸渍法或共沉淀法制备了Cu/ZrO2催化剂。考察了ZrO2载体的制备方法以及Cu/ZrO2的制备参数对催化剂性能的影响。采用BET、XRD、TEM及XRF等方法对催化剂的比表面积、孔容、晶相、表面形貌以及活性组分等进行了表征。同时,制备并比较了Ni/ZrO2、Cu/10MgO-90ZrO2和Cu/10CaO-90ZrO2催化剂的性能,考察了活性组分Cu、Ni的差异以及ZrO2载体的影响。在Cu/ZrO2催化剂(Cu的质量分数为8%)上,500 ℃~600 ℃乙醇转化率达到98%~100％、H2选择性为2.0~2.6（摩尔比）。 Cu/ZrO2与Ni/ZrO2机械混合有助于H2选择性的提高。在催化剂载体中添加MgO、CaO碱性物质可以使H2选择性提高1.3倍~2.0倍。浸渍法制备的Cu/ZrO2催化剂的性能优于共沉淀法。     

Ethanol steam reforming over Ni-Cu/Al2O3-MyOz （M = Si, La, Mg, and Zn） catalysts

Ni-based catalysts doped with copper additives were studied on their role in ethanol steam reforming reaction.The effects of Ca content,support species involving Al2O3-SiO2,Al2O3-MgO,Al2O3-ZnO,and Al2O3-La2O3,on the catalytic performance were studied.Characterizations by TPR,XRD,NH3-TPD,XPS,and TGA indicated that catalysts 30Ni5Cu/Al2O3-MgO and 30NiSCu/Al2O3-ZnO have much higher H2 selectivity than 30NiSCu/Al2O3-SiO2,as well as good coke resistance.H2 selectivity for 30Ni5Cu/Al2O3-MgO catalyst was 73.3% at 450℃ and increased to 94.0% at 600 ℃,whereas for 30NiSCu/Al2O3-ZnO catalyst,the H2 selectivity was 63.6% at 450 ℃ and 95.2% at 600 ℃.These Al2O3-MgO and Al2O3-ZnO supported Ni-Cu bimetallic catalysts may have important applications in the production of hydrogen by ethanol steam reforming reactions.     

焙烧温度对合成低碳醇用Cu/Mn/Ni/ZrO2催化剂性能的影响

 研究了焙烧温度对合成低碳醇用Cu／Mn／Ni／ZrO2催化剂结构及催化性能的影响．随着焙烧温度的升高，催化剂的催化活性和产物分布都发生较大的变化．催化剂在较低的温度下焙烧，低温下反应液相产物的分布符合S－F方程；反应温度升高时，液相产物中主要是甲醇和异丁醇；在高温下焙烧的催化剂，其催化活性较低，但即使在较低的反应温度下，异丁醇在液相高级醇（C2＋OH）中也是主要的产物．结合其他的一些反应结果与XRD，BET，TPR及EXAFS等表征结果，认为焙烧温度使催化剂的结构发生了较大的变化，进而影响催化剂各组分之间的相互作用，从而使催化剂对合成低碳醇反应表现出不同的催化性能．     

Ni/ZrO2催化剂上甲烷水蒸气重整反应的研究

研究了Ni/ZrO2催化剂对甲烷水蒸气重整制合成气的反应性能。考察了催化剂的还原温度、载体焙烧温度以及反应温度、原料配比和空速等对催化剂性能的影响。利用XRD、TEM、XPS等手段对催化剂的织构形貌进行了表征。研究表明，Ni/ZrO2催化剂用于甲烷水蒸气重整制合成气不仅具有较高的活性，也具有较好的稳定性。水蒸气比增加，CH4转化率增大、CO选择性下降。CH4转化率及CO选择性均随空速增大而下降。使用10%Ni/ZrO2催化剂，在650 ℃、空速1.984×104 h－1、原料气配比H2O∶CH4∶N2=2∶1∶2.67的条件下，获得CH4转化率85%、CO选择性70%的结果。     

Design of Multiple Metal Doped Ni Based Catalyst for Hydrogen Generation from Bio-oil Reforming at Mild-temperature

A new kind of multiple metal (Cu, Mg, Ce) doped Ni based mixed oxide catalyst, synthesized by the co-precipitation method, was used for efficient production of hydrogen from bio-oil reforming at 250-500 oC. Two reforming processes, the conventional steam reforming (CSR) and the electrochemical catalytic reforming (ECR), were performed for the bio-oil reforming. The catalyst with an atomic mole ratio of Ni:Cu:Mg:Ce:Al=5.6:1.1:1.9:1.0:9.9 exhibited very high reforming activity both in CSR and ECR processes, reaching 82.8% hydrogen yield at 500 oC in the CSR, yield of 91.1% at 400 oC and 3.1 A in the ECR, respectively. The influences of reforming temperature and the current through the catalyst in the ECR were investigated. It was observed that the reforming and decomposition of the bio-oil were significantly enhanced by the current. The promoting effects of current on the decomposition and reforming processes of bio-oil were further studied by using the model compounds of bio-oil (acetic acid and ethanol) under 101 kPa or low pressure (0.1 Pa) through the time of flight analysis. The catalyst also shows high water gas shift activity in the range of 300-600 oC. The catalyst features and alterations in the bio-oil reforming were characterized by the ICP, XRD, XPS and BET measurements. The mechanism of bio-oil reforming was discussed based on the study of the elemental reactions and catalyst characterizations. The research catalyst, potentially, may be a practical catalyst for high efficient production of hydrogen from reforming of bio-oil at mild-temperature.     

Cu/Ni负载型Beta分子筛催化剂的乙醇水蒸气重整制氢催化性能研究

采用等体积浸渍的方式,在全硅Beta分子筛载体上担载Cu、Ni活性组分,制备出一系列xCuyNi-ABZ多功能乙醇水蒸气重整制氢催化剂。通过XRD、TEM、SEM-EDX以及XPS等多种表征手段,研究催化剂的结构特性、活性组分含量等因素对催化性能的影响,依据反应产物分布,揭示其作用机理。结果表明,以Beta分子筛为载体可促使活性组分以纳米颗粒的形式高度分散于载体表面,并且存在较强的载体-金属作用力。与传统SiO_2为载体催化剂相比,2.5Cu2.5Ni-ABZ催化剂具备良好的乙醇水蒸气重整催化性能,当反应温度为450℃,实现100%的乙醇转化率和67.23%的H_2选择性,且副产物CO(4.14%)、CH_4(5.65%)含量相对较低。这可归因于Cu和Ni活性组分间的高效协同作用,Cu具有良好的乙醇脱氢性能,生成反应中间体乙醛;在反应过程中,乙醛的重整和分解是两个受温度影响的竞争反应,Ni组分利用其较强的C-C键断裂能力,随温度的升高,乙醛重整反应占主导作用,生成目标产物H_2。通过对反应后样品分析表明,2.5Cu2.5Ni-ABZ催化剂具备良好的抗烧结和抗积炭催化性能。     

Effect of Transition Metals (Cu, Co and Fe) on the Autothermal Reforming of Methane over Ni/Ce0.2Zr0.1Al0.7Oδ Catalyst

The transition metals (Cu, Co, and Fe) were applied to modify Ni/Ce0.2Zr0.1Al0.7Oδ catalyst.The effects of transition metals on the catalytic properties of Ni/Ce0.2Zr0.1Al0.7Oδ autothermal reforming of methane were investigated. The Ni-supported catalysts were characterized by XRD, TPR and XPS.Tests in autothermal reforming of methane to hydrogen showed that the addition of transition metals (Cu and Co) significantly increased the activity of catalyst under the conditions of lower reaction temperature,and Ni/Cu0.05Ce0.2Zr0.1Al0.65Oδ was found to have the highest conversion of CH4 among all catalysts in the operation temperatures ranging from 923 K to 1023 K. TPR, XRD and XPS measurements indicated that the cubic phases of CexZr1-xO2 solid solution were formed in the preparation process of catalysts.Strong interaction was found to exist between NiO and CexZr1-xO2 solid solution. The addition of Cu improved the dispersion of NiO, inhibited the formation of NiAl2O4, and thus significantly promoted the activity of the catalyst Ni/Cu0.05Ce0.2Zr0.1Al0.65Oδ.     

Synergism between constituents of multicomponent catalysts designed for ethanol steam reforming using partial least squares regression and artificial neural networks

Effects of different catalyst components on the catalytic performance in steam reforming of ethanol have been investigated by means of Artificial Neural Networks (ANNs) and Partial Least Square regression (PLSR). The data base consisted of ca. 400 items (catalysts with varied composition), which were obtained from a former catalyst optimization procedure. Marten's uncertainty (jackknife) test showed that simultaneous addition of Ni and Co has crucial effect on the hydrogen production. The catalyst containing both Ni and Co provided remarkable hydrogen production at 450°C. The addition of Ceas modifier to the bimetallic NiCo catalyst has high importance at lower temperatures: the hydrogen concentration is doubled at 350°C. Addition of Pt had only little effect on the product distribution. The outliers in the data set have been investigated by means of Hotelling T2 control chart. Compositions containing high amount of Cu or Ce have been identified as outliers, which points to the nonlinear effect of Cu and Ce on the catalytic performance. ANNs were used for analysis of the non-linear effects: an optimum was found with increasing amount of Cu and Ce in the catalyst composition. Hydrogen production can be improved by Ce only in the absence of Zn. Additionally, negative cross-effect was evidenced between Ni and Cu. The above relationships have been visualized in Holographic Maps, too. Although predictive ability of PLSR is somewhat worse than that of ANN, PLSR provided indirect evidence that ANNs were trained adequately.     

在Ni/HZSM-5催化剂上低温水蒸汽重整生物油制氢

We investigated high catalytic activity of Ni/HZSM-5 catalysts synthesized by the impregna-tion method, which was successfully applied for low-temperature steam reforming of bio-oil. The influences of the catalyst composition, reforming temperature and the molar ratio of steam to carbon fed on the stream reforming process of bio-oil over the Ni/HZSM-5 catalysts were investigated in the reforming reactor. The promoting effects of current passing through the catalyst on the bio-oil reforming were also studied using the electrochemical catalytic re-forming approach. By comparing Ni/HZSM-5 with commonly used Ni/Al₂O₃ catalysts, the Ni₂₀/ZSM catalyst with Ni-loading content of about 20% on the HZSM-5 support showed the highest catalytic activity. Even at 450 oC, the hydrogen yield of about 90% with a near complete conversion of bio-oil was obtained using the Ni₂₀/ZSM catalyst. It was found that the performance of the bio-oil reforming was remarkably enhanced by the HZSM-5 supporter and the current through the catalyst. The features of the Ni/HZSM-5 catalysts were also investigated via X-ray diffraction, inductively coupled plasma and atomic emission spectroscopy, hydrogen temperature-programmed reduction, and Brunauer-Emmett-Teller methods.     

Ni/Al2O3和Fe/Al2O3催化剂催化乙醇水蒸气重整制氢的对比研究

甲醇、乙醇等低碳醇催化重整制氢是燃料电池氢源的重要技术之一.乙醇和甲醇相比,更容易存储,低毒且可以从生物质经发酵获得[1,2].乙醇可以通过裂解、部分氧化、水蒸气重整和氧化重整等途径制氢[3~6].已有的文献表明,Pt、Ru、Rh、Pd等贵金属可有效地催化乙醇重整反应,载体多选用