ZrCdOx/SAPO-18双功能催化剂催化CO2加氢合成低碳烯烃性能

采用并流共沉淀法制备了不同Zr/Cd原子比(n_Zr/n_Cd)的ZrCdO_x金属氧化物,并与水热法制备的不同硅铝比(n_{SiO_(2})/n_{Al_(2}O₃))的片状SAPO-18分子筛物理混合制得ZrCdO_x/SAPO-18双功能催化剂,研究了其催化CO₂加氢直接合成低碳烯烃性能。采用透射电子显微镜(TEM)、X射线衍射(XRD)、N2吸附-脱附、CO₂程序升温脱附(CO₂-TPD)、NH3程序升温脱附(NH3-TPD)和X射线光电子能谱(XPS)对催化剂进行了分析。与单一ZrO2相比,引入CdO使得ZrCdO_x比表面积下降,当n_Zr/n_Cd=8时制备的Zr8Cd1氧化物呈现出无定形小颗粒状,Zr与Cd之间较强的协同作用使得Zr Cd Ox氧化物产生了更多的氧空位,有利于CO₂的吸附活化。通过对Zr8Cd1金属氧化物与SAPO-18(硅铝比0.1)的质量比、工艺反应温度、压力和空速对催化性能影响的考察,获得了最佳反应条件。研究还发现,当SAPO-18的硅铝比从0.1降为0.01时,Br?nsted酸含量降低,产物中烯烃/烷烃物质的量之比从18.6提高至37.2,但副产物CO含量迅速增加,低碳烯烃时空收率明显下降。     

ZrCdOx/SAPO-18双功能催化剂催化CO2加氢合成低碳烯烃性能

采用并流共沉淀法制备了不同Zr/Cd原子比（n_Zr/n_Cd）的ZrCdO_x金属氧化物，并与水热法制备的不同硅铝比（n_SiO2/n_{Al2O3）的片状SAPO-18分子筛物理混合制得ZrCdOx/SAPO-18双功能催化剂，研究了其催化CO2加氢直接合成低碳烯烃性能。采用透射电子显微镜（TEM）、X射线衍射（XRD）、N2吸附-脱附、CO2程序升温脱附（CO2-TPD）、NH3程序升温脱附（NH3-TPD）和X射线光电子能谱（XPS）对催化剂进行了分析。与单一ZrO2相比，引入CdO使得ZrCdOx比表面积下降，当nZr/nCd=8时制备的Zr8Cd1氧化物呈现出无定形小颗粒状，Zr与Cd之间较强的协同作用使得ZrCdOx氧化物产生了更多的氧空位，有利于CO2的吸附活化。通过对Zr8Cd1金属氧化物与SAPO-18（硅铝比0.1）的质量比、工艺反应温度、压力和空速对催化性能影响的考察，获得了最佳反应条件。研究还发现，当SAPO-18的硅铝比从0.1降为0.01时，Brø；nsted酸含量降低，产物中烯烃/烷烃物质的量之比从18.6提高至37.2，但副产物CO含量迅速增加，低碳烯烃时空收率明显下降。}     

TheT g displacement measurements: A way to foresee the physical behaviour and the use of glassy polymers

The effect of ageing temperature (belowT _g) on physical ageing of glassy PET has been investigated by differential scanning calorimetry. The position of the glass transition endotherm was found to be strongly dependent on the annealing conditions (time, annealing temperature). A single relaxation time model is proposed for the analysis of physical ageing.The variations of the equilibrium relaxation time _iso with annealing temperature allow the determination of the parameters of the model. Finally, using these constants, one can determine the thermal past and foresee the thermal future of unknown samples which are of prime importance in processes using temperatures around the glass transition temperature.

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Zusammenfassung Mittels DSC wurde der Einfluß der Alterungstemperatur (unterhalbT _g) auf das physikalische Altern von glasartigen PET untersucht. Die Lage der Glasumwandlungsendothermen hängt stark von den Temperungsbedingungen (Dauer, Temperungstemperatur) ab. Es wird ein Relaxationszeitmodell für die Analyse physikalischen Alterns vorgeschlagen.Die Parameter dieses Modelles knnen aus der Änderung der Gleichgewichtsrelaxationszeit _iso mit der Temperungstemperatur ermittelt werden. Unter Benutzung dieser Konstanten kann die thermische Vergangenheit unbekannter Proben bestimmt und die thermische Zukunft derselben vorhergesagt werden, was für Vorgänge bei Temperaturen um den Glasumwandlungspunkt von primärer Wichtigkeit ist.

     

不同聚合物分散剂对Pt/SAPO-11催化剂性能的影响

采用浸渍法制备了经过不同聚合物分散剂处理的Pt/SAPO-11催化剂,并通过X射线衍射(XRD)、透射电子显微镜(TEM)、N₂吸附-脱附和N_H3程序升温脱附(TPD)等对催化剂的组织结构进行了表征。结果表明,分散剂不会破坏催化剂的结构,反而提高了其孔体积、孔径和比表面积,同时改变了沸石的酸强度和酸量,其中以聚乙烯吡咯烷酮处理的Pt/SAPO-11催化剂孔体积、孔径和酸性分布最佳。在固定床反应器上对不同分散剂处理的Pt/SAPO-11催化剂催化性能进行评价,结果表明聚乙烯吡咯烷酮处理的Pt/SAPO-11催化剂也表现出最佳的催化性能,麻风树油的加氢脱氧率高达99.45%,生物航空煤油组分收率和异构烷烃组分(C₈~C₁₆)的选择性分别达到了44.67%和56.37%。     

不同聚合物分散剂对Pt/SAPO-11催化剂性能的影响

采用浸渍法制备了经过不同聚合物分散剂处理的Pt/SAPO-11催化剂,并通过X射线衍射(XRD)、透射电子显微镜(TEM)、N₂吸附-脱附和NH₃程序升温脱附(TPD)等对催化剂的组织结构进行了表征。结果表明,分散剂不会破坏催化剂的结构,反而提高了其孔体积、孔径和比表面积,同时改变了沸石的酸强度和酸量,其中以聚乙烯吡咯烷酮处理的Pt/SAPO-11催化剂孔体积、孔径和酸性分布最佳。在固定床反应器上对不同分散剂处理的Pt/SAPO-11催化剂催化性能进行评价,结果表明聚乙烯吡咯烷酮处理的Pt/SAPO-11催化剂也表现出最佳的催化性能,麻风树油的加氢脱氧率高达99.45%,生物航空煤油组分收率和异构烷烃组分(C₈~C₁₆)的选择性分别达到了44.67%和56.37%。     

不同聚合物分散剂对Pt/SAPO-11催化剂性能的影响

采用浸渍法制备了经过不同聚合物分散剂处理的Pt/SAPO-11催化剂，并通过X射线衍射(XRD)、透射电子显微镜(TEM)、N₂吸附-脱附和NH₃程序升温脱附(TPD)等对催化剂的组织结构进行了表征。结果表明，分散剂不会破坏催化剂的结构，反而提高了其孔体积、孔径和比表面积，同时改变了沸石的酸强度和酸量，其中以聚乙烯吡咯烷酮处理的Pt/SAPO-11催化剂孔体积、孔径和酸性分布最佳。在固定床反应器上对不同分散剂处理的Pt/SAPO-11催化剂催化性能进行评价，结果表明聚乙烯吡咯烷酮处理的Pt/SAPO-11催化剂也表现出最佳的催化性能，麻风树油的加氢脱氧率高达99.45%，生物航空煤油组分收率和异构烷烃组分(C₈~C₁₆)的选择性分别达到了44.67%和56.37%。     

B-frame supported bimetallics. [(PMe2ph)2PtB9H11Ru(η-PrC6H4Me)] and [(PMe2ph)2PtB9H9Ru(η-PrC6H4Me)]; an interesting pair of electron-deficient nido and closo geometries

[7,7-(PMe₂Ph)₂-9-(η⁶-^isoPrC₆H₄Me)-7,9-PtRuB₉H₁₁] has a formal closo Wadian cluster-electron count, but a nido geometry, whereas [1-(η⁶-^isoPrC₆H₄Me)-4,4-(PMe₂Ph)₂-1-4-RuPtB₉H₉], which does have a closo geometry, has a formal sub-closo cluster electron count; both compounds are formed in the reaction between [6-(η⁶-^isoPrC₆H₄Me)-nido-6 RuB₉H₁₃], KH and [PtCl₂(PMe₂Ph)₂].     

固溶体Bi_2Mo_(1-x)W_xO_6的水热合成及光催化性能

采用水热法,在较低温度下合成了系列Bi2Mo1-xWxO6固溶体。结果表明,W的替代抑制了固溶体的晶粒生长,导致了较小的晶粒尺寸。随着x的增加,红外光谱中840cm-1处M-O键的振动频率νM-O有规律地向低频率方向移动,表明Mo6+离子逐步被W6+替代,生成了无限互溶的固溶体。光吸收性能研究表明,随着W6+逐步替代Mo6+,带隙出现了先降后升的趋势,x=0.4时带隙最小。而固溶体的光催化性能随着x的增加,出现了先增后减的趋势,x=0.4时光催化活性最高。此外,含W样品的光催化活性高于Bi2MoO6。这与固溶体的带隙、带结构和晶粒尺寸变化有关。     

Effect of the template on synthesis of SAPO-11 for hydroisomerization of n-octane

Summary In this study, five typical dialkylamines with different alkyl chains were tested as template for synthesis of SAPO-11. Among these templates, diethylamine, dipropylamine and diisopropylamine have been shown to be effective for synthesis of SAPO-11. SAPO-11 synthesized with dipropylamine in the gels of high Si content and diisopropylamine in the gels of low Si content exhibit good catalytic performance in hydroisomerization of n-octane.     

不同硅铝比Cu-ZSM-5纳米片上N2O催化分解

以双季铵盐表面活性剂为模板剂,水热条件下合成了硅铝比(nSi/nAl)为18、26和95的ZSM-5沸石纳米片,采用离子交换方法制备了铜改性的ZSM-5纳米片样品,并测试了其催化分解N_2O性能。结合X射线衍射(XRD)、N_2吸附/脱附、X射线荧光光谱(XRF)、扫描电镜(SEM)、透射电镜(TEM)、氢气程序升温还原(H_2-TPR)、氧气程序升温脱附(O_2-TPD)和原位红外漫反射光谱(CODRIFT)等表征结果 ,探讨了沸石硅铝比对于催化剂N_2O分解性能的影响及其原因。结果表明,ZSM-5纳米片硅铝比越低,CuZSM-5纳米片催化剂的活性越高。催化活性的提高归因于低硅铝比催化剂上Cu~+活性物种可还原性的增强和吸附氧脱附能力的提高。     

用于NO_x低温下吸附还原的CoO_x/CeO_2二元氧化物的制备

研究了以多孔二氧化硅微球和活性炭为载体制备NOx吸附/还原催化剂的方法,摸索了最佳Ce/Co物质的量的比例。采用低温氮吸附方法测定了样品的BET比表面和孔容,利用XRD方法表征了样品中所掺杂的金属元素的晶型。研究发现:当nCe/nCo=75/25时,材料获得最佳NOx吸附能力,当以多孔二氧化硅微球作载体时,材料对于NOx的吸附主要来自CoOx和CeO2的二元氧化物;当以活性炭作为载体时,活性炭参与了NOx的吸附,因此其吸附容量大大提高。对NOx的吸附机理进行了探讨,并研究了样品的NH3还原性质。     

Production of 1,3-Butadiene From C4 Raffinate-3 Through Oxidative Dehydrogenation of n-Butene Over Bismuth Molybdate Catalysts

Recent progress on the bismuth molybdate catalysts for oxidative dehydrogenation of n-butene to 1,3-butadiene was reported in this review. A number of bismuth molybdate catalysts, including pure bismuth molybdates (α-Bi₂Mo₃O₁₂, β-Bi₂Mo₂O₉, and γ-Bi₂MoO₆) and multicomponent bismuth molybdates, were prepared by a co-precipitation method for use in the production of 1,3-butadiene from C₄ raffinate-3 through oxidative dehydrogenation of n-butene. It was observed that multicomponent bismuth molybdate catalyst was more efficient than pure bismuth molybdate catalyst in the oxidative dehydrogenation of n-butene. Various experimental measurements such as temperature-programmed reoxidation, X-ray photoelectron spectroscopy, and O₂-temperature-programmed desorption analyses were carried out to elucidate the different catalytic activity of bismuth molybdate catalysts. It was revealed that a bismuth molybdate catalyst with a higher oxygen mobility showed a better catalytic performance in terms of conversion of n-butene and yield for 1,3-butadiene. We have successfully demonstrated from experimental findings that oxygen mobility of bismuth molybdate catalyst played a key role in determining the catalytic performance in the oxidative dehydrogenation of n-butene to 1,3-butadiene.     

Synthesis, thermal stability and magnetic properties of the Lu1−xLaxMn2O5 solid solution

Polycrystalline samples of the Lu_1−xLa_xMn₂O₅ solid solution system were synthesized under moderate conditions for compositions with x up to 0.815. Due to the large difference in ionic size between Lu³⁺ and La³⁺, significant changes in lattice parameters and severe lattice strains are present in the solid solution. This in turn leads to the composition dependent thermal stability and magnetic properties. It is found that the solid solution samples with x≤0.487 decompose at a single well defined temperature, while those with x≥0.634 decompose over a temperature range with the formation of intermediate phases. For the samples with x≤0.487, the primary magnetic transition occurs below 40 K, similar to LuMn₂O₅ and other individual RMn₂O₅ (R=Bi, Y, and rare earth) compounds. In contrast, a magnetic phase with a 200 K onset transition temperature is dominant in the samples with x≥0.634.     

NO2对Cu/SAPO-34分子筛催化剂上NH3选择性催化还原NO性能的影响

主要考察了NO₂对Cu/SAPO-34 分子筛催化剂在整个温度范围内（100-500 ℃）NH₃选择性催化还原（SCR）NO性能的影响. 研究所使用样品为新鲜Cu/SAPO-34 催化剂在750 ℃下水热处理4 h 的稳定期样品.通过X射线衍射（XRD）和扫描电子显微镜（SEM）对样品的结构以及形貌进行表征,采用SCR活性评价、动力学实验以及原位漫反射傅里叶变换红外光谱（in situ-DRIFTS）表征催化剂的性能以及催化剂表面物种的变化. 活性评价实验结果表明,NO₂会抑制催化剂的低温（100-280 ℃）活性,但其存在会提高催化剂的高温（280 ℃以上）活性. 与此同时,随着反应物中NO/NO₂的摩尔比例减少,由于NH₄NO₃物种的分解,副产物（N₂2O）的浓度增大. 动力学结果表明,Cu/SAPO-34 催化剂上快速SCR反应的表观活化能（E_a=64.02 kJ·mol^-1）比标准SCR反应的表观活化能（E_a=48.00 kJ·mol^-1）更大. In situ-DRIFTS实验结果表明NO比NO₂更容易在催化剂表面形成硝酸盐,并且NO₂更容易与吸附在Brønsted 酸性位上的NH₃物种反应生成NH₄NO₃. 低温下,催化剂表面的NH₄NO₃物种会覆盖SCR反应的活性位,造成活性降低,但在高温时,形成的NH₄NO₃物种一部分会被NO还原为N2,而另一部分会直接热分解为N₂O,造成催化剂的选择性降低.     

XRD and Si MAS-NMR spectroscopy across the β-Lu2Si2O7-β-Y2Si2O7 solid solution

Samples in the system Lu_2−xY_xSi₂O₇ (0?x?2) have been synthesized following the sol-gel method and calcined to 1300 °C, a temperature at which the β-polymorph is known to be the stable phase for the end-members Lu₂Si₂O₇ and Y₂Si₂O₇. The XRD patterns of all the compositions studied are compatible with the structure of the β-polymorph. Unit cell parameters are calculated as a function of composition from XRD patterns. They show a linear change with increasing Y content, which indicates a solid solubility of β-Y₂Si₂O₇ in β-Lu₂Si₂O₇ at 1300 °C. ²⁹Si MAS NMR spectra of the different members of the system agree with the XRD results, showing a linear decrease of the ²⁹Si chemical shift with increasing Y content. Finally, a correlation reported in the literature to predict ²⁹Si chemical shifts in silicates is applied here to obtain the theoretical variation in ²⁹Si chemical shift values in the system Lu₂Si₂O₇-Y₂Si₂O₇ and the results compare favorably with the values obtained experimentally.     

SiO2/TiO2-xCx/C的制备、表征及其吸附和可见光催化性能

以SiO2为成核中心,钛酸四丁酯为钛源,分别以多羟基化合物乙二醇、丙三醇、葡萄糖和聚乙烯醇为联接剂,采用水解沉淀法制备了碳掺杂和包覆的多孔SiO2/TiO2-xCx/C可见光响应型光催化剂。采用X-射线衍射(XRD)、透射电子显微镜(TEM)、X-射线光电子能谱(XPS)、傅里叶变换-红外光谱(FTIR)、比表面积(BET)和紫外-可见(UV-Vis)漫反射光谱对样品进行表征。对不同结构样品的形成机理进行了分析。以次甲基蓝(MB)溶液为模拟废水,对样品的吸附性能和可见光催化性能进行了评价。结果表明,多羟基化合物对材料的结构和性能有重要影响。碳的掺杂和包覆使材料的吸收光谱包含了整个可见光区,而多孔结构使材料的吸附性能得到提高。以聚乙烯醇为原料所得样品吸附性能最好,30 min内吸附率达到70%;而以丙三醇为原料所得样品具有最好的可见光催化性能,40 min内次甲基蓝的降解率达到95%。     

Catalytically Promoted NOx Sorption by ZrO2-Based Oxides

Metal promoted zirconia-based oxide sorbents, such as Pt–ZrO₂/Al₂O₃ for NO _x have been investigated. To clarify the role of the catalyst component, sorption of NO and NO₂ was compared using the samples with and without Pt. The catalytic oxidation of NO to NO₂ and successively to nitrate ions is an important role for the Pt catalyst. The experimental results indicate that a high-temperature calcination is essential to remove residual Cl from Pt–ZrO₂–Al₂O₃ prepared from H₂PtCl₆ in order to provide more active NO _x sorption sites. Of M–ZrO₂–Al₂O₃ samples investigated, ruthenium as well as Pt demonstrated relatively good performance as a catalyst component in the sorbent. The FT-IR spectra after sorption of NO and NO₂ demonstrated a strong band attributed to stored nitrate ions. The Pt catalyst was more resistant to sulfur poisoning than a base metal catalyst. However, the NO _x sorptive capacities of the Pt–ZrO₂/Al₂O₃ sorbents were expected to be deteriorated in dilute SO₂ as far as observed from FT-IR spectra.     

水在C12-EOx-C12•2Br/正己醇/正庚烷W/O微乳中的状态

以FT-IR方法研究了水/C₁₂-EO_x-C₁₂•2Br/正己醇/正庚烷形成的W/O微乳中水的状态. 结果表明, 其中的水存在4种状态, 分别为阳离子头基结合水、反离子结合水、类似本体的水以及束缚在微乳栅栏层中的水. 由解卷积技术分解FT-IR谱图, 进而获得每个表面活性剂分子对应于这4种状态水分子的数目n_N＋, n_Br-, n_b和n_f. 随着水含量(W₀)增加, n_b急剧增大, n_N＋少许上升, 而n_f和n_Br-维持不变, 这说明微乳水核逐渐长大, 且在所考察W₀范围内, 表面活性剂头基解离度保持不变.     

Effect of annealing temperature on the structural and optical properties of Zn1−xMgxO particles prepared by oxalate precursor

Zn_1−xMg_xO particles were prepared using zinc and magnesium oxalate precursor by co-precipitated method. The lattice constants of Zn_1−xMg_xO proved that the interstitial Mg formed at 500 °C and Mg replaced Zn in ZnO tetrahedral coordination at 800 °C. Compared with the ZnO, the absorbing band edge of the Zn_1−xMg_xO displayed blue shifts. The room temperature photoluminescence was similar to ZnO and variation of Mg content did not change the shape or peak position of the emission spectra markedly when it was annealed at 500 °C. However, its blue emission band disappeared, and a relatively strong green light emission at 498 nm appeared after annealed at 800 °C. The photoluminescence intensity ratios I_(green)/I_(UV) of Zn_1−xMg_xO varied with Mg content and the green light emission peak shifted from 498 nm to 472 nm when Mg content increased from 0 to 2.0 at.%.     

Transformation ofn-hexane over microporous molecular sieves: Studies over MeAPO-11 and MeAPSO-11

CoAPO-11, MgAPO-11, ZnAPO-11, COAPSO-11, ZnAPSO-11 and MgAPSO-11 samples were synthesized by hydrothermal methods and characterized. The samples were loaded with 0.5 wt.% Pt and tested for their catalytic activities in the isomerization ofn-hexane. All the samples exhibited catalytic activities and selectivities for isomerization comparable to that of SAPO-11. The selectivities for the different monomethyl and dimethyl isomers are rationalized on the basis of shape selectivity and acidities of different samples.