负载型La0.8Sr0.2MnO3燃烧催化剂的载体效应

Combustion catalysts La0.8Sr0.2MnO3 supported on γ-Al2O3, α-Al2O3, cordierite (2MgO•2Al2O3•5SiO2) and ZrO2 were compared. Further investigation was focused on LSM/ γ-Al2O3 catalyst. It was observed that LSM/γ－Al2O3 catalyst loaded with 20% (mass fraction) LSM (La0.8Sr0.2MnO3 or corresponding oxides), heated at 750℃ or above, perovskite-type oxides were found by XRD examination, whereas, the same catalyst loaded with 10% or less LSM, perovskite oxides were absent, calcination temperature about 750℃ is necessary for the formation of perovskite structure in LSM/γ-Al2O3 catalysts. High activity of complete oxidation of xylen will be obtained when perovskite-type oxides.
Investigation of TPR showed that neat LSM or LSM/γ-Al2O3(20%) was reduced by H2-N2 mixed gas. Two degradation processes took place. In the first, reduced temperature peak was about 350 - 450℃. If reduction ended at 400℃, perovskite structure was retained, which may be due to the reduction of Mn3+to Mn2+ on the surface of LSM only. In the second process, perovskite structure was destroied, and La2O3, Mn2O3, Mn - Sr - O oxides could be obtained, which took place in the temperature range 685 - 750℃ and ended at 800℃. This was proved by TPR experiments (Fig. 3, 5) and XRD patterns (Fig. 4)
Catalysts LSM/γ-Al2O3(10% or 20%) heated at 500℃ have only one TPR peak, i. e. lower temperature peak. This is due to the absence of perovskite-type oxides in the catalysts. However, neat LSM or LSM/γ-Al2O3(20%) heated 750℃ or above, not only the first low temperature TPR peak but also the second peak, which is contributed by the perovskite-type oxides in these catalysts appeared. Therefore, the second TPR peak, i. e. the higher temperatue peak is a characteristic peak for perovskite-type oxides in the reduced process. When LSM/ γ-Al2O3 (10%) catalys is heated at 750℃, no perovskite-type oxides were detected by XRD, and the second reduction peak was absent also in TPR process. \
The order of the second reduction peak temperature(characteristic peak of perovskite - type ox- ides) is: neat LSM(750℃）> LSM/γ-Al2O3 20% (685-698℃) -deposited LSM/γ-Al2O3 (698℃) > LSM/γ-Al2O3 15% (677 - 680℃) >(LSM/γ-AL2O3 10% 620 - 630℃, for Mn - Al - O medium oxides on surface). It is correleted with the increasing of the effect of support sequentially.
When LSM/γ-Al2O3 catalysts were heated at 900℃, more stable phase, spinel MnAl2O4 appeared, which could be proved by TPR of model catalyst MnAl2O4/γ-Al2O3.     

负载型La0.8Sr0.2MnO3燃烧催化剂的载体效应

用浸渍法制备负载型Ｌａ_（０．８）Ｓｒ_（０．２）Ｍｎｏ_３燃烧催化剂,比较了γ－ＡＩ_２Ｏ_３、α－ＡＩ_２Ｏ_３、堇青石（２ＭｇＯ·２Ａｌ_２Ｏ_３、５ＳｉＯ_２）和ＺｒＯ_2四种载体的负载效果．用ＸＲＤ,ＤＰＲ着重研究了γ－Ａｌ_２Ｏ_３载体上由于负载量不同、焙烧温度不同引起的催化剂物相变化和二甲苯完全氧化的催化活性变化．     

负载型La0.8Sr0.2CoO3燃烧催化剂中Co(Ⅱ)与载体γ-Al2O3的相互作用

一般认为稀土钙钛矿型La0.8Sr0.2CoO3是CO氧化、碳氢(HC)化合物完全氧化和NOx还原的良好氧化物催化剂.用复合硝酸盐溶液浸渍γ-Al2O3制取负载型催化剂La0.8Sr0.2CoO3/γ-Al2O3(LSC/γ-Al2O3),负载量15%(质量分数).采用XRD, TPR, BET和二甲苯完全氧化催化剂活性测试等手段,研究了CoAl2O4的形成过程,催化剂经750 ℃焙烧, Co(Ⅱ)已进入γ-Al2O3体相,并有大量的CoAl2O4尖晶石形成. 若在γ-Al2O3表面涂敷一层以MgAl2O4为主相的覆盖层,在一定程度上能够阻挡Co2+离子进入γ-Al2O3的晶格,并有效地生成出LSC活性相,提高了其完全氧化的催化活性.     

负载型La0.8Sr0.2CoO3燃烧催化剂的载体效应

负载型Ｌａ０．８Ｓｒ０．２ＣｏＯ３／β－Ａ）催化剂,由于钴离子在不太高的温度下易和载体γ－ＡＩ２Ｏ３作用形成ＣｏＡｌ２Ｏ４尖晶石或在尖晶石,因而不能有效地成为ＣＯ、ＨＣ化合物完全氧化的催化剂,采用ＸＲＤ、ＢＥＴ、ＤＴＡ、ＴＧ和二甲苯完全氧化催化活性测试等手段,研究了ＣｏＡｌ２Ｏ４的形成过程,可以认为这是一个放热、释氧而失重的过程,并伴有晶胞的稍微增大,若在γ－ＡＩ２Ｏ３表面涂数一层以ＭｇＡｌ２Ｏ４     

钯系高分子载体催化剂对硝基苯液相加氢催化活性的研究

制备了以弱碱性（ＡＨ－１、ＡＨ－２ХＨ）、中等碱性（ＡＨ－３１、ЭⅡЭ－１０∏）以及强碱性（ＡＢ－１７－８、ＡＢ－１６ΓＣ）等阴离子交换树脂为载体的钯系催化剂,测定了它们硝基苯催化加氢的活性,其中Ｐｄ－ＡＨ－１、Ｐｄ－ＡＢ－１６ГＣ和Ｐｄ－ＡＢ－１７－８的活性较好。本文还分析了树脂结构对催化活性的影响。     

第二载体ZrO_2、TiO_2、γ－Al_2O_3对燃烧催化剂耐热性的影响

第二载体ＺｒＯ_２、ＴｉＯ_２、γ－Ａｌ_２Ｏ_３对燃烧催化剂耐热性的影响周仁贤，郑小明，朱波，仲逸芬，陈敏（杭州大学化学系，杭州，３１００２８）关键词催化氧化，钯，铂，第二载体燃烧催化剂多数采用堇青石陶瓷蜂窝体为载体基体，活性氧化铝为涂层料。很多结晶态...     

以ZrO2—Al2O3为载体Co—Mo—K耐硫变换催化剂的TPR研究

利用程序升温还原（ＴＰＲ）技术,研究了ＺｒＯ２对Ｃｏ／Ａｌ２Ｏ３、Ｍｏ／Ａｌ２Ｏ３、Ｍｏ－Ｋ／Ａｌ２Ｏ３以及Ｃｏ－Ｍｏ－Ｋ耐硫催化剂氧化还原性能的影响。结果表明,ＺｒＯ２的引入,使活性组分在载体表面分散的更好,促进了Ｍｏ－Ｋ活性相的形成,使ｏ和Ｍｏ的还原变得容易,并起到抑制催化剂在反应中被重新氧化的作用。     

La助剂添加方式对甲烷催化燃烧用Mn/Al2O3催化剂的影响

采用等体积浸渍法制备了La改性的Mn/Al2O3催化剂.以甲烷燃烧反应为探针反应,考察了La2O3的引入方法对其催化活性的影响.催化剂的物化性质经TPR,XRD和XPS表征.研究结果表明,La的添加顺序对催化剂的物化性质和催化活性有显著影响.在以共浸渍方式制备的催化剂A中,载体与锰物种之间的相互作用大受削弱,锰晶粒变小,分散度增加,催化剂的活性显著提高,甲烷转化率为50%,对应的反应温度比未加L丑时降低了90℃.在先浸LB后浸Mn制备的催化剂C中,La的存在也使催化剂的催化活性大大改善,效果与催化剂A相当.当以先浸Mn后浸La的方式加入助剂时,催化剂B的比表面积降低,催化活性下降.     

镧对V2O5/γ-Al2O3催化剂在异丁烷脱氢中活性的影响

V2O5／γ-Al2O3是用于异丁烷脱氢的新型催化剂，引入适量的镧不仅可改善活性组分的分散度，提高催化脱氢活性，而且还增强了催化剂的抗积炭能力，通过FTIR，BET，TG，TPR和TEM等手段研究了镧对催化剂性能的影响。     

Kombucha SCOBY Waste as a Catalyst Support

It is established that food waste can be repurposed to extend its lifecycle and decrease its carbon footprint. In this work, SCOBY (symbiotic culture of bacteria and yeast) waste from kombucha tea production has been repurposed as a catalyst support. Copper nanoparticles (Cu NPs) have been embedded in a piece of treated SCOBY via an in-situ method which enabled the catalyst, inCu/t-SCOBY, to be easily recycled. In addition, inCu/t-SCOBY catalyzed the full reduction of 4-nitrophenol in an excess of sodium borohydride (NaBH₄) within 20 minutes. After 6 additional catalytic cycles, the catalyst maintained up to 50% of its performance in the first cycle. Characterization of the catalyst has also been done to understand the mechanism of action and interactions occurring between t-SCOBY and Cu NPs. The results of this work clearly present a proof-of-concept in utilizing porous wastes materials such as SCOBY as catalyst supports, allowing metallic NPs to be efficacious and practical heterogenous catalysts.     

碳化钨用作质子交换膜燃料电池催化剂载体的抗氧化性能

 采用还原碳化法制备了碳化钨样品,并用原位还原法担载Pt粒子得到Pt/WxCy催化剂. 利用计时电流技术对Pt/WxCy和常规Pt/C催化剂进行氧化处理,并用循环伏安法测试了氧化前后两种催化剂的电化学活性面积. 将两种催化剂制成单电池,对比研究了其氧化后的性能衰减. 结果表明, Pt/WxCy催化剂制成的单电池抗氧化能力显著高于普通Pt/C制成的单电池.     

在Pt/Al2O3催化剂上苯的内扩散对负0.9级动力学的影响

在Pt/Al₂O₃催化剂上用外循环反应器研究了内扩散对苯完全氧化动力学的影响,当用30～40目(即0.45～0.60mm)催化剂时反应在动力学区域进行.若O₂过量时则动力学区域苯的完全氧化可用-0.9级速率方程描述.当催化剂粒径增至φ6×5mm时,反应在内扩散区域进行并变为一0.1级反应.催化剂有效因子η在0.24～0.12之间.在同一温度下,η_实验随苯分压p_苯的增加而增大;而p_苯相近时,η_实验则随温度的升高而减小.动力学区域的反应活化能为55.5kJ/mol,内扩散区域的反应活化能为34.9kJ/mol,其值约为动力学区域的活化能与苯分子扩散活化能的算术平均值.     

Yb2O3对Bi2O3-MoO3催化剂性能的影响

在Bi2O3-MoO3复合氧化物催化剂中加入Yb2O3，可明显提高异丁烯转化率和生成甲基丙烯醛的选择性，用XRD、FT-Raman光谱和SEM技术研究了催化剂的组成和性质，Bi2O3—MoO3催化剂的成分主要是α-Bi2Mo3O12，添加镱后出现了Yb2Mo3O12的吸收峰；且Bi2O3-MoO3-Yb2O3催化剂的FT—Raman光谱图在363cm^-1处出现了Yb—O伸缩振动峰，同时既Bi2O3-MoO3催化剂的铝-氧振动发生红移，表明镱的加入使铝-氧键的振动减弱，使Bi2O3-MoO3-Yb2O3催化剂有较高传递晶格氧给予异丁烯的能力，导致异丁烯转化率和生成甲基丙烯醛的选择性均显著提高。     

钯杂多酸/SBA-15的合成及正十六烷的催化氧化

将钯杂多酸锚定在3-氨丙基-三乙氧基硅烷(APTS)修饰的SBA-15孔道内, 得到了一种新型、高效的钯杂多酸/SBA-15 (Pd₃Bi₂W₂₂/SBA-15)多相催化材料. 采用XRD和FT-IR红外光谱对催化剂进行了表征, 并检测了其对正十六烷氧化的催化性能. 结果表明, 以空气为氧化剂, 在无任何溶剂的条件下, 该催化剂对正十六烷烃氧化成醇类和酮类显示出了优良的催化性能, 并且可多次回收利用.     

以ZrO_2-Al_2O_3为载体的Co-Mo-K耐硫水煤气变换催化剂

采用沉淀法和浸渍法分别制备了 Zr O2 - Al2 O3复合载体和 Co- Mo- K耐硫变换催化剂 .研究了 Zr O2 对 Co- Mo- K耐硫变换催化剂活性及热稳定性的影响 .利用 XRD、BET、TG、XPS等手段对催化剂及其载体的结构、吸硫吸水性能和氧化还原性能进行了表征 .结果表明以 Zr O2 - Al2 O3代替传统的 γ- Al2 O3作为 Co- Mo- K耐硫变换催化剂的载体 ,可提高催化剂的活性 ,尤其是低温活性 ,并可改善催化剂的热稳定性、氧化还原性、吸硫和吸水性能     

第二组分对Au/CeO2催化剂甲醇部分氧化性能的影响

本文研究了Pd、Pt、Ru和Ag对Au/CeO2催化剂以及Pd含量对Au-Pd/CeO2催化剂甲醇部分氧化性能的影响,并运用XRD、TPD和TPR等手段对Au/CeO2和Au-Pd/CeO2催化剂进行了表征.结果表明,Pd和Pt的加入能提高Au/CeO2催化剂的活性,而Ru和Ag的加入效果正好相反.不同的Au/Pd比对Au-Pd/CeO2催化剂的活性和H2选择性的影响不同,其中Au/Pd=60:40的效果最好,因为Au60Pd40/CeO2催化剂形成的富Au型AuxPdy较多,甲醇的吸附温度较低和对反应产物H2的吸附较少.     

Au纳米粒子植入Zr-金属有机框架化合物（Zr-MOF）用于催化水介质中的A3-偶联反应

水热条件下,ZrCl4与2,2’-联吡啶-5,5’-二甲酸(dipydc)配位聚合形成Zr基金属-有机框架化合物(Zr-MOF).将HAuCl4乙醇溶液引入Zr-MOF中,Au3+离子被原位还原得到Au/Zr-MOF催化剂.由于高度分散的极细的金纳米粒子以及底物在催化剂微孔孔道中的吸附和扩散,Au/Zr-MOF催化剂在各种水介质的A3-偶联反应中显示出较高的活性.该催化剂便于回收和套用,在重复使用5次后,催化活性没有显著地降低.