Pt-NbOx/C、Pt-ZrO2/C复合氧电极催化剂的制备及性能研究

以NbOx、ZrO2作为助催化剂,采用分步法制备得到Pt-NbOx/C、Pt-ZrO2/C复合催化剂,采用XRD、SEM等手段分析了催化剂的物相及形貌特征。通过循环伏安法、阴极极化曲线等电化学方法对催化剂的电化学性能进行了研究。结果表明,Pt均匀分布在载体表面,颗粒大小均在5 nm以下;NbOx和ZrO2的加入没有改变氧的还原反应机理,与Pt/C、Pt-ZrO2/C催化剂相比,Pt-NbOx/C复合催化剂催化氧电化学还原过程的活性有了明显提高。     

Rh/C催化剂的制备及其催化性能研究

以RhCl3.3H2O为前驱体,活性炭为载体,采用浸渍法制备了Rh/C催化剂,并使用场发射透射电镜对催化剂进行了表征。同时考察了制备条件对Rh/C催化剂在6-羟基-3,4-二氢异喹啉-2-甲酸甲酯-3-甲酸乙酯加氢反应中催化性能的影响。     

CeO2稳定PEMFC阴极催化剂制备与性能研究

传统的质子交换膜燃料电池阴极铂碳催化剂虽然具有较高的氧还原活性,但其稳定性还需要进一步提高。本文通过加入富含氧缺陷的CeO₂纳米颗粒提高铂碳催化剂的氧还原活性和稳定性。研究表明采用共沉淀-酸处理法合成的CeO₂纳米颗粒存在大量的Ce³⁺,说明该方法制备的CeO₂中含有丰富的氧缺陷。将Pt或PtCo合金纳米颗粒负载在CeO₂/C上制备成的催化剂显示了良好的性能：当C∶CeO₂=2∶1(质量比)时,Pt-CeO₂/C催化剂活性最高,半波电位达到了0.868 V,且催化稳定性较20%Pt/C大幅提高,经过1×10⁴次连续循环后,20%Pt/C的质量活性衰减了82.2%,而Pt-CeO₂/C催化剂的质量活性衰减仅为13.8%;以PtCo-CeO₂/C(2∶1)为阴极催化剂的单电池最大输出功率为1.02 W·cm^-2。     

铥改性MnCeOx/TiO2催化剂在氨中低温还原NOx的优越性能

采用溶胶-凝胶法制备了MnCeTm_yO_x/TiO₂(y为Tm/Mn摩尔比,y=0.1,0.3,0.5)低温SCR脱硝催化剂,研究和分析了TmO_x对催化剂脱硝性能的影响。所研制的MnCeTmO_x/TiO₂催化剂提高了以氨为还原剂的低温选择性催化还原(SCR)脱硝性能,并采用XRD、NH₃-TPD分析探究了TmO_x的作用及内在机制。结果表明,当y=0.3时,催化剂具有最佳的脱硝效果,在150℃具有95%以上的NO_x转化率。对催化剂进行了稳定性测试和不同空速下的性能测试结果表明,MnCeTm_0.3O_x/TiO₂催化剂具有良好的稳定性,且在两种空速下均能保持优异的低温NH₃-SCR脱硝性能。     

离子交换树脂对Pt/C催化剂耐久性的影响

离子交换树脂（Ionomer）是质子交换膜燃料电池催化层的重要组成部分,它在催化层中的主要作用是作为质子传导相传导质子。本文采用旋转圆盘电极法（RDE）,在模拟燃料电池真实的运行环境（模式一）和模拟燃料电池启停环境（模式二）两种模式下,研究了Ionomer对铂碳催化剂电压循环耐久性的影响。通过相同位置透射电镜分析法（IL-TEM）,分析了铂碳催化剂经历模式二耐久性测试后的结构变化。研究发现Ionomer的存在可以提高铂碳催化剂的耐久性。在模式一的测试中:添加Ionomer后,其氧还原半波电位下降值?E从23 mV下降至11 mV;没有发生碳的腐蚀,Pt颗粒的长大是催化剂性能下降的主要原因;Ionomer的存在延缓了Pt电化学比表面积（ECSA）的降低从而有利于保持Pt的活性。在模式二的测试中:添加Ionomer后,其氧还原半波电位下降值?E从25 mV下降至5 mV,除了铂颗粒长大外还发生了载体碳的腐蚀;Ionomer的存在同样可以保持Pt的活性;IL-TEM分析可以看到明显的铂颗粒长大和碳腐蚀,碳载体的腐蚀造成铂的严重流失和团聚。含Nafion的催化剂中铂颗粒平均粒径从2.7 nm增加到了3.76 nm,不含Nafion的催化剂中的铂颗粒平均粒径从2.44 nm增加到了4.19 nm。      

CeOx-MnOx/TiO2低温SCR催化剂的制备及脱硝性能

利用超声浸渍法分别制备了MnOx/TiO2和CeOx-MnOx/TiO2低温选择性催化还原（SCR）脱硝催化剂,并对其进行了SEM、EDS、BET及XPS等表征,在此基础上,研究了催化剂的低温SCR脱硝性能,重点考察了Mn负载量及Ce/Mn摩尔比对催化剂性能的影响,结果表明：当Mn负载量为15%时,催化剂具有较高的催化活性;Ce的掺杂有利于催化剂催化活性的提升,当Ce/Mn=0.8时,其催化活性最高,在180℃时达到了97.86%。另外,Ce的掺杂有利于提升催化剂的抗硫抗水特性,但仍有待进一步提升。     

除盐水加氢催化除氧试验研究

以强碱性阴离子交换树脂为载体负载纳米金属钯制备催化树脂,研究了催化树脂的特性及其对除盐水加氢除氧的催化作用.结果表明:载钯树脂的催化活性高、稳定性好;在载钯树脂的催化作用下,用除盐水加氢除氧,溶解氧质量浓度可降到20μg/L以下,水温、p H对除氧基本无影响,溶解氧去除率随氢气加入量增加而升高,低运行流速对除氧基本无影响,运行流速大于50 m/h,溶解氧去除率下降.     

Ni/海泡石及Ni-Sm/海泡石催化剂的研究

采用海泡石为载体,金属镍为活性组份,稀土为助剂,用不同方法制备了Ｎｉ／Ｓｅｐ 和Ｎｉ－Ｓｍ ／Ｓｅｐ 催化剂,并考察了它们的苯加氢反应性能。结果表明：Ｎｉ／Ｓｅｐ 催化剂的活性明显高于Ｎｉ／Ａｌ２Ｏ３,稀土Ｓｍ 对Ｎｉ／Ｓｅｐ 催化剂有较大的改性作用。ＴＰＲ、ＴＰＤ、ＣＯ吸附结果表明,海泡石和钐能使镍的还原温度降低,氢吸附量增大,活性中心增加,同时使镍原子电子密度增高。     

含氧复合型Pt/C催化剂的制备、表征及其对甲醇电氧化催化性能的研究

利用亚锡酸对氯铂酸的弱的多步骤还原制备新型Pt/C催化剂.用XRD、HRTEM、EDS、DSC以及氢吸附电化学对所制备的催化剂进行了表征,并用循环伏安和恒电位极化对其进行了甲醇电氧化催化活性测定.实验结果表明,应用亚锡酸法合成的Pt/C催化剂具有很高的甲醇电氧化催化活性,在0.5V(SCE)电位下,其质量活性约为亚硫酸路线合成的Pt/C催化剂的2倍.亚锡酸法可在纳米尺度范围内生成金属Pt和Pt氧化物共存的复合型碳载催化剂,这种含氧复合型催化剂可以促进Pt在甲醇电氧化过程中双功能作用的有效协调.     

Study on Modification of Sm2O3 by Ni／Sepiolite Catalyst

A series of Ni-Sm/sepiolite catalysts were prepared by impregnation. The modification of Sm2O3 for Ni/sepiolite was investigated by TPR, XPS and poisoning of CS2, respectively. The results indicate that the addition of Sm2O3 improves the activity of hydrogenation and anti-poisoning ability of Ni/sepiolite catalyst, and it also increases the dispersion of nickel atoms over support and the amount of active nickel atoms in catalyst. Effect of Sm203 on Ni/sepiolite catalyst ineludes not only electronic effect but also steric effect, whereas electronic effect seems to be principal.     

Effects of Cerium Oxide on Ni／Al2O3 Catalysts for Decomposition of CH4 and C2H4

Characteristics of carbon deposition of CH4 and C2H4 decomposition over supported Ni and Ni-Ce catalysts were studied by using a pulse reaction as well as BET, TPR, XPS and hydrogen chemisorption techniques. It is found that there is a metal-semiconductor interaction (MScI) in the Ni-Ce catalyst, and the effect of MScI on the carbon deposition of CH4 decomposition is opposite to that of C2H4. A novel model of carbon deposition of CH4 or C2H4 decomposition was proposed.     

H_3PW_6Mo_6O_(40)·nH_2O催化过氧化氢清洁氧化环己酮合成己二酸

以自制H3PW6Mo6O40.nH2O为催化剂,在无有机溶剂、相转移催化剂的情况下,用过氧化氢氧化环己酮合成己二酸。探讨了催化剂用量、过氧化氢用量、反应时间、反应温度对反应的影响。确定了最佳反应条件为n(环己酮)∶(n磷钼钨杂多酸)∶(n过氧化氢)=100∶0.15∶400,在90℃反应5h,己二酸的分离收率达75.8%。     

La_2O_3掺杂对V_2O_5-WO_3/TiO_2催化剂SCR性能的影响

通过共沉淀法将La组分掺入到TiO_2载体中,采用浸渍法将V和W组分负载到La_2O_3-TiO_2复合氧化物上,制备出V2O5-WO3/La_2O_3-TiO_2催化剂。考察不同La_2O_3掺杂量对其NH3催化还原NO性能的影响,同时通过多种物理化学手段进行表征分析。XRD,NH_3-in situ DRIFTS,H_2-TPR,XPS和UV-vis DRS测试结果表明,元素La与Ti以La-O-Ti键相互作用,生成高度分散的镧物种,也使得TiO_2具有更好的热稳定性,但由于LaO_x物种与VO_x物种和WO_x物种之间的相互作用,降低了催化剂的氧化还原性和表面Brnsted酸数量,从而降低了其催化活性。     

Effects of Support on Catalytic Behavior of Combustion Catalyst La0.8Sr0.2CoO3/γ-Al2O3

Combustion catalyst La0.8Sr0.2CoO3 (LSC) is expected to possess relatively high activity for the oxidation of carbon monoxide and many hydrocarbons. If γ-Al2O3 is used as its support, cobalt ions can easily react with γ-Al2O3 at not very high temperature to form spinel CoAl2O4 or spinel-like, which decreases the activity of the combustion catalyst. In this paper, MgAl2O4 and CaAl2O4 were pre-coated on γ-Al2O3 by impregnation respectively, which formed compound support for LSC. It is shown that, when MgAl2O4 layer is covered on the surface of MgAl2O4 by impregnation, the entering of cobalt ions into γ-Al2O3 lattice is restrained, then LSC formed on the surface of MgAl2O4, which leads to a good catalytic activity of xylene complete oxidation. But the layer of MgAl2O4 should be thick enough to reach 30% (mass fraction) MgO in the support due to large size particle of MgAl2O4 crystalline. If polyvinyl alcohol (PVA) is added into the impregnation solution adequately, MgAl2O4 particles formed on the surface of γ-Al2O3 are getting smaller, and less amount of MgAl2O4 is needed to cover up the surface of γ-Al2O3. If CaAl2O4 layer substituted for MgAl2O4, more closed cover is obtained in virtue of fine particles of CaAl2O4. The activity examination shows that smaller particles of MgAl2O4 or CaAl2O4 can be more effective to hinder cobalt ions entering the lattice of γ-Al2O3, and better activities will be obtained.     

Ln2O3／X—13分子筛作酯化反应催化剂的研究

用浸渍-焙烧法制备的Ln2O3／X－13分子筛（Ln＝Nd、Sm、Tm、Lu、Eu、Dy），其稀土氧化物含量为0．83％～0．93％，该分子筛对芳香酸、脂肪酸与醇的酯化反应有明显的催化作用．芳香酸酯化反应转化率以合成邻苯二甲酸二辛酯（DOP）为例，它比无催化剂的转化率提高10％左右，比X－13分子筛的催化转化率提高8％左右；脂肪酸酯化反应转化率以合成棕酸辛酯（IOP）为例，它比无催化剂的转化率提高7％左右，比X－13分子筛的催化转化率提高4％左右．而且，Ln2O3／X－13分子筛与Ln2O3／Al2O3型酯化反应催化剂相比，其稀上用量下降25％左右．酯化反应温度下降10℃左右．上述结果表明．Ln2O3／X－13分子筛是一种优良的酯化反应催化剂。     

Ln2O3/MgO催化合成增塑剂IOP的研究

采用共沉淀-焙烧法制成了LnO3／MgO(Ln=Nd，Sm，Er)担载型催化剂。该型催化剂比表面大，分散性好。在催化合成IOP中效果明显，且使Ln2O3的用量减少80％左右。     

Nd对Ru/Al2O3氨合成催化剂性能的影响

采用等体积浸渍法制备了一系列Ru-Nd/Al2O3氨合成催化剂。通过TPD、CO化学脉冲吸附法等手段研究了Nd对催化剂的性能影响。结果表明,Nd的加入抑制了H2的吸附,促进了N2的解离吸附,同时修饰了载体,使Ru金属分散度提高。研究还表明,当Nd的含量在8%左右,反应温度在475℃时,催化剂的活性最高。     

Influence of V2O5 Addition on Reduction of NO by C3H6 over Pt/V2O5/Al2O3 Monolithic Catalyst

Pt/V2O5/Al2O3 and Pt/Al2O3 monolithic catalysts were prepared by wet impregnation method, and the influence of V2 O5 addition on the catalytic activity for NO reduction by C3 H6 under lean burn condition was investigated in detail.The results show that Pt/V2O5/Al2O3 has better activity of NO reduction than Pt/Al2O3 , adding V2O5 to Pt catalyst makes the temperature window of NO reduction shift further to a lower temperature region.The activity of NO reduction decreases and there is a similar degree of deactivation over the two catalysts in the presence of SO2 in feed gas.Moreover, adding V2 O5 to Pt catalyst resulted in improvement of resistance to SO2 oxidation, which decreases the emission of sulfate particulate.Thermal aging treatment counteractes the promoting effect of V2O5 on NO reduction.     

Effect of Fe2O3 Loading Amount on Catalytic Properties of Monolithic Fe2O3/Ce0.67Zr0.33O2 -Al2O3 Catalyst for Methane Combustion

Ce0.67Zr0.33O2-Al2O3 solid solution was prepared by the co-precipitation method. Fe2O3-based catalysts supported on the solid solution were obtained by the impregnation method. The article revealed that the optimal loading amount of Fe2O3 on Ce0.67Zr0.33 O2-Al2O3 in our experimental condition for catalytic combustion of methane was 8% （ mass fraction）. The prepared catalysts were characterized by BET, TPR, XRD analyses, and their catalytic activity was investigated after being calcined at 873 K and after being aged in water gas at 1273 K. When the loading amount of Fe203 was 8% （ mass fraction）, the catalyst held the highest activity, and the best temperature speciality and thermal stability. The complete-conversion temperature of methane for fresh and aged sample was 788 and 838 K, respectively. The range between the light-off temperature and the complete-conversion temperature was only 15 K. The characterization results of XRD indicated that Fe2O3 was well dispersed on the Ce0.67Zr0.33O2-Al2O3 matrix. The results of BET and TPR were in good harmony with the catalytic activity results.