磷化镍/介孔TiO_2催化剂的制备及其催化加氢脱硫性能

以介孔TiO2(m-TiO2)为载体,采用程序升温还原法制备了Ni2P/m-TiO2催化剂,考察了不同起始Ni/P摩尔比及活性组分负载量对该催化剂结构及其催化加氢脱硫(HDS)性能的影响.结果表明,当Ni/P摩尔比为1.25时,活性组分以Ni2P为主,催化剂的最佳Ni负载量为10%.采用X射线衍射、低温N2吸附-脱附、场发射扫描电镜和程序升温还原等技术表征了m-TiO2及其它不同载体负载的Ni2P催化剂.结果表明,高结晶度m-TiO2载体使Ni和P物种的还原温度大幅度降低,在450～600oC还原制得的Ni2P/m-TiO2催化剂的结构参数基本一致,比表面积均为90m2/g左右,具有很高的热稳定性和对二苯并噻吩的HDS催化性能.在相同的反应条件下,m-TiO2负载的Ni2P催化剂HDS性能最好,各载体负载的Ni2P催化剂活性大小顺序为Ni2P/m-TiO2Ni2P/SiO2Ni2P/P25.     

H_3PW_(12)O_(40)掺杂TiO_2介孔材料的制备及光催化性能

以P123为模板剂,采用溶胶-凝胶的溶剂热合成方法制备了H3PW12O40掺杂TiO2介孔材料H3PW12O40/TiO2.利用紫外可见漫反射吸收光谱(UV-vis/DRS)、X射线粉末衍射(XRD)、N2吸附和透射电子显微镜(TEM)手段对所制备的材料进行结构表征,罗丹明B(RB)为模型污染物评价其光催化性能.结果表明,所制备的介孔材料具有锐钛矿与板钛矿复合的晶型结构、大的BET比表面积和孔径均匀分布的介孔结构.光催化实验表明,H3PW12O40/TiO2可将罗丹明B完全矿化.     

介孔TiO2-ZnO复合薄膜的制备与表征

以三嵌段聚合物P123为模板剂, 以钛酸异丙酯和二水乙酸锌为无机前驱体, 利用溶胶-凝胶法和旋涂法成功地制备了不同ZnO含量的介孔TiO2-ZnO复合薄膜. 在ZnO前驱体摩尔分数为0~50％范围内获得薄膜质量较高的介孔TiO2-ZnO复合薄膜. 用小角XRD、扫描电子显微镜(SEM)、高分辨透射电子显微镜(HRTEM)、能谱仪(EDS)、紫外-可见吸收光谱(UV-Vis)及X射线光电子能谱(XPS)对所得的复合薄膜进行了表征和分析. EDS和XPS等研究证明介孔薄膜为TiO2和ZnO的复合体系, 且ZnO前驱体含量的增加仍能保持TiO2-ZnO复合薄膜的均匀性. UV-Vis研究结果表明, 介孔复合薄膜的光学带隙宽度为3.45-3.58 eV, 随着ZnO含量的增加, 复合薄膜的紫外吸收蓝移.     

BiVO4/TiO2复合光催化剂的制备及可见光降解腐殖酸

首先以P123为模板剂利用溶胶-凝胶法制备TiO2载体,然后采用沉淀法制得介孔BiVO4/TiO2复合光催化剂.采用X射线衍射仪、漫反射吸收光谱仪、比表面分析仪对所制得的光催化剂进行了表征.结果表明,催化剂样品中的TiO2主要以锐钛矿型存在,BiVO4为四方相和单斜相共存的混晶,与单纯的BiVO4、TiO2光催化剂相比,BiVO4/TiO2复合光催化剂具有更高的可见光吸收性能、较好的比表面积和均一的介孔结构.腐殖酸的可见光降解试验表明,随着腐殖酸初始浓度的增大,其光降解率逐渐降低,ln(C/C0)对t呈线性关系.试验同步研究了腐殖酸光催化降解过程中荧光光谱、红外光谱和GC-MS谱图的变化情况.     

锐钛相介孔SO2-4/TiO2的声化学制备及结构和催化酯化性能

不使用有机模板剂,采用超声化学法一步水解制得吸附硫酸根的介孔偏钛酸,500℃焙烧得到介孔SO2-4/TiO2固体超强酸.用XRD、TFEM、FTIR、低温氮吸附-脱附等手段对催化剂结构进行了表征.结果表明,硫酸根在焙烧过程中与前驱体介孔偏钛酸孔壁上自由羟基的键合起到了孔结构导向及支撑作用,500℃焙烧后样品具有161 m2·g-1的比表面积及4.1 nm的平均孔径,酸强度H0介于-14.52与-16.02之间,硫含量为2.8%,晶型全部为锐钛矿相,介孔SO2-4/TiO2具有较大比表面、强酸特性和稳定性.催化合成富马酸二甲酯的最佳条件为:n(甲醇):n(富马酸)=6:1,催化剂用量为1.0%(反应物总质量),带水剂苯用量为10 mL,反应时间为3 h,催化剂重复使用7次,酯化率大于90%.     

TiO2/CdS/Ru(bpy)2(NCS)2作为太阳电池光阳极的探讨

将CdS纳米粒子复合成TiO2纳米多孔膜上，用染料Ru(bpy)2(NCS)2对此复合半导体纳米膜电极进行每化，测量了不同CdS复合量的ITO／TiO2/CdS/Ru(bpy)2(NCS)2光阳极组成光电池的能量转换效率，实验证明，ITO／TiO2/CdS/Ru(bpy)2(NCS)2作为太阳电池光阳极的能量转换效率与TiO2/CdS复合半导体中CdS的含量有关，当CdS复合时间为5min的电池的短路电流为5．23A／m^2,开路电压为0．716V，能量转换效率为0．77％。     

三维有序介孔/大孔TiO2微球的制备、表征及光催化性能

以聚甲基丙烯酸甲酯微球为模板,分别以钛酸四丁酯和四异丙醇钛为钛源,通过溶胶-凝胶法辅助模板法制得TiO2纳米微球前驱体,并用程序升温控制其焙烧温度,最终成功制得了具有三维有序介孔/大孔复合结构的TiO2微球.以罗丹明B(RhB)为模型污染物,探索了以不同钛源制备得到的介孔/大孔复合TiO2微球的光催化性能;并采用XRD、SEM、TEM、UV-vis DRS、比表面积测试、光催化性能测试等对样品的晶粒尺寸、物相、形貌、光吸收、比表面积及性能等进行了分析.结果表明,运用溶胶凝胶法辅助模板法能够合成结晶度高、形貌规整、比表面积大、光催化活性良好的锐钛矿相TiO2微球.     

复合模板剂下有序介孔TiO2的制备研究

在复合模板剂聚氧乙烯十二烷基醚(Brij35）和聚乙二醇（PEG)下，制备出有序介孔TiO2.用XRD、HRTEM、SEM、FT-IR和N2吸附脱附等方法进行表征；并通过对反应过程中电导率和粘度的连续监测，分析有序介孔TiO2形成过程.研究表明,介孔TiO2为规整的六方排列结构，在低于400 ℃焙烧，有序结构稳定性高，比表面积达252 m2•g－1，孔径3.4 nm，晶型为锐钛矿；经500 ℃焙烧，有序介孔结构破坏，并开始出现金红石型晶相.有序介孔TiO2形成过程是基于在高极性介质中非极性的碳氢链聚集成为胶束，同时钛酸丁酯（TBOT）在已形成的胶束上聚集，在酸作用下不断水解缩聚而形成有序介孔结构，有效控制水解和聚合过程是控制介孔材料结构形成的关键.     

锐钛相介孔SO42-/TiO2的声化学制备及结构和催化酯化性能

不使用有机模板剂,采用超声化学法一步水解制得吸附硫酸根的介孔偏钛酸,500℃焙烧得到介孔SO2-4/TiO2固体超强酸.用XRD、TFEM、FTIR、低温氮吸附-脱附等手段对催化剂结构进行了表征.结果表明,硫酸根在焙烧过程中与前驱体介孔偏钛酸孔壁上自由羟基的键合起到了孔结构导向及支撑作用,500℃焙烧后样品具有161 m2·g-1的比表面积及4.1 nm的平均孔径,酸强度H0介于-14.52与-16.02之间,硫含量为2.8%,晶型全部为锐钛矿相,介孔SO2-4/TiO2具有较大比表面、强酸特性和稳定性.催化合成富马酸二甲酯的最佳条件为:n(甲醇):n(富马酸)=6:1,催化剂用量为1.0%(反应物总质量),带水剂苯用量为10 mL,反应时间为3 h,催化剂重复使用7次,酯化率大于90%.     

活性炭孔结构对TiO2/AC复合光催化剂光催化活性的影响

以4种表面化学性质相近, 而孔结构差异较大的活性炭(AC)为原料, 采用酸催化水解法合成了系列TiO2/AC复合催化剂, 考查活性炭孔结构对复合光催化剂活性的影响. 以苯酚为模型物, 考察了催化剂的活性;以低温(77 K)液氮吸附测定活性炭的比表面积、孔容和孔径分布;以Boehm滴定及元素分析定量表征活性炭表面化学性质. 以SEM观测复合催化剂表面TiO2的分散性能;以X射线衍射(XRD)、漫反射光谱(DRS)测试光催化剂晶相结构参数及光吸收阈值. 结果表明, 活性炭孔结构性质对TiO2/AC活性影响显著. AC1、AC2、AC3、AC4对TiO2活性提高的协同系数分别为1.55、2.03、1.28、1.43. 协同系数大小与接触界面面积变化值(⊿S)趋势相似. 具有发达的微孔及适量中孔结构的TiO2/AC复合光催化剂的催化活性最高.     

硅纳米管负载的钌基催化剂费-托合成催化性能研究

以模板法合成的硅纳米管（SNT）为载体,用浆态浸渍法制备了钌基催化剂,采用氮气物理吸附、透射电子显微镜（TEM）、X射线粉末衍射（XRD）和氢气程序升温还原（H₂-TPR）等手段对其进行了表征。在固定床反应器上（503K,1.0MPa）考察了该催化剂的费-托合成反应活性及产物选择性,并与用商业二氧化硅为载体制备的催化剂上的反应结果进行了比较。结果表明,SNT和SiO₂负载的氧化钌在623K可被H₂完全还原;SNT负载的钌基催化剂上,钌氧化物颗粒较小、分散性好,还原后钌颗粒被较好地分散在硅纳米管上,且几乎所有的钌颗粒都分布在管内。与以SiO₂为载体的催化剂相比,以硅纳米管为载体的钌基催化剂具有较高的费-托合成活性。     

构筑可控催化氧化性能催化剂用于醇的转化

通过金属离子替代的方法设计了催化氧化性能不同的Mg-Al-Ru-CO₃类水滑石、Co-Al-Ru-CO₃类水滑石和Ru-Co(OH)₂-CeO₂等三种催化剂. XRD实验表明钌部分替换制得的Mg-Al-Ru-CO₃和Co-Al-Ru-CO₃可保持水滑石的结构; 但用铈替代铝之后得到的Ru-Co(OH)₂-CeO₂催化剂无法保持水滑石的结构， 而是由氢氧化钴和二氧化铈的微晶组成. XPS 和Ru K-edge XAFS的测试结果证实Mg-Al-Ru-CO3催化剂中钌被等键长的6个氧原子包围， 该催化剂可有效地催化氧化醇类； Co-Al-Ru-CO₃催化剂中钌被两种键长不等的6个氧原子包围， 其中短键长的Ru═O是催化氧化性能增强的原因； Ru-Co(OH)₂-CeO₂催化剂中钌被两种键长不等的5个氧原子包围， 其对于各类醇均有高效的催化氧化性能， 原因归功于配位数少的钌物种.     

Catalytic properties of Ru nanoparticles embedded on ordered mesoporous carbon with different pore size in Fischer-Tropsch synthesis

A series of 3 wt% Ru embedded on ordered mesoporous carbon (OMC) catalysts with different pore sizes were prepared by autoreduction between ruthenium precursors and carbon sources at 1123 K. Ru nanoparticles were embedded on the carbon walls of OMC. Characterization technologies including power X-ray diffraction (XRD), nitrogen adsorption-desorption, transmission electron microscopy (TEM), and hydrogen temperature-programmed reduction (H₂-TPR) were used to scrutinize the catalysts. The catalyst activity for Fischer-Tropsch synthesis (FTS) was measured in a fixed bed reactor. It was revealed that 3 wt% Ru-OMC catalysts exhibited highly ordered mesoporous structure and large surface area. Compared with the catalysts with smaller pores, the catalysts with larger pores were inclined to form larger Ru particles. These 3 wt% Ru-OMC catalysts with different pore sizes were more stable than 3 wt% Ru/AC catalyst during the FTS reactions because Ru particles were embedded on the carbon walls, suppressing particles aggregation, movement and oxidation. The catalytic activity and C₅₊ selectivity were found to increase with the increasing pore size, however, CH₄ selectivity showed the opposite trend. These changes may be explained in terms of the special environment of the active Ru sites and the diffusion of products in the pores of the catalysts, suggesting that the activity and hydrocarbon selectivity are more dependent on the pore size of OMC than on the Ru particle size.     

Supported Ru catalysts prepared by two sonication-assisted methods for preferential oxidation of CO in H2

The preferential oxidation (PROX) of CO in the presence of H(2) is an important step in the production of pure H(2) for industrial applications. In this report, two sonochemical methods (S1 and S2) were used to prepare highly dispersed Ru catalysts supported on mesoporous TiO(2) (TiO(2)(MSP)) for the PROX reaction, in which a reaction gas mixture containing 1% CO + 1% O(2) + 18% CO(2) + 78% H(2) was used. The supported Ru catalysts performed better than the supported Au and Pt catalysts, and the S1 and S2 methods are superior to the impregnation method. The Ru/TiO(2)(MSP) catalysts were active for the PROX reaction below 200 °C and good for the methanation reactions of CO and CO(2) above 200 °C. The presence of residual chlorine in the catalysts severely suppressed their PROX reaction activity, and a higher dispersion of Ru particles led to better catalytic performances. The addition of Au in the Ru/TiO(2)(MSP) catalyst also caused a poorer catalytic activity for both the PROX and the methanation reactions. TPR results showed that in the active catalysts prepared by the S1 and S2 methods, the well dispersed Ru particles, after calcination in air, had a stronger interaction with the support than those in the catalyst prepared by the impregnation method and in the Au-Ru/TiO(2)(MSP) catalyst. In situ CO absorption experiments performed with the diffusion reflectance Fourier transform infra red (DRIFT) method showed that the bridged adsorbed CO species on isolated Ru(0) sites correlated with the catalytic performances, indicating that these isolated Ru(0) sites are the most active sites of the Ru/TiO(2)(MSP) catalysts in the PROX reaction.     

Catalytic behavior of Al2O3-TiO2 supported Pd-Ru bimetallic catalyst for the partial hydrogenation of palm oil

Summary Al₂O₃-TiO₂ supported Pd-Ru bimetallic catalysts were prepared and characterized by X-ray photoelectron spectroscopy and X-ray diffraction (XRD) techniques. The catalytic system was evaluated in the partial hydrogenation of palm oil. Based on these results, it was deduced that core-shell model particles, with Ru cores, would be most likely formed in the bimetallic catalysts. As a result, the dispersing effect of ruthenium on palladium and the charge transfer from ruthenium to palladium may be closely related to the excellent catalytic performance. Besides, the highly dispersed TiO₂ on γ-alumina support seems to be crucial for inhibiting the formation of trans fatty acid.     

Organosoluble zirconium phosphonate nanocomposites and their supported chiral ruthenium catalysts: the first example of homogenization of inorganic-supported catalyst in asymmetric hydrogenation

In this article, we report the synthesis, structure, morphologies, and asymmetric catalytic properties of a series of novel organosoluble zirconium phosphonate nanocomposites and their supported chiral ruthenium catalysts, which have a good organosolubility (0.1-0.5 g mL(-1)) in various solvents and mesoporous, filiform, and layered structures. Due to the organosoluble properties in various organic solvents, the first homogenization of zirconium phosphonate-supported catalyst was realized in the field of catalysis. In the asymmetric hydrogenation of substituted α-ketoesters, enantioselectivities (74.3-84.7% ee) and isolated yields (86.7-93.6%) were higher than the corresponding homogeneous Ru(p-cymene)(S-BINAP)Cl(2) due to the confinement effect caused by the remaining mesopores in the backbone of the zirconium phosphonate. After completing the reaction, the supported catalyst can be readily recovered in quantitative yield by adding cyclohexane and centrifugation, and reused for five consecutive runs without significant loss in catalytic activity.     

Multi-wall carbon nanotubes supported ruthenium for glucose hydrogenation to sorbitol

Multi-wall carbon nanotubes (MWNTs) supported ruthenium prepared with an impregnation method was used as catalyst in glucose hydrogenation to sorbitol. The effects of ruthenium loading, reaction time, temperature and initial hydrogen pressure on glucose hydrogenation were investigated. Compared with Raney Ni and ruthenium supported on Al₂O₃, SiO₂, Ru/MWNTs showed higher catalytic activity.     

Ru/SBA-15的制备及其对水煤气变换反应的催化作用

制备了中孔分子筛SBA-15,以SBA-15为载体采用真空浸渍法制备了负载型Ru基水煤气变换反应的催化剂。利用透射电子显微镜、X-射线粉末衍射等方法对样品进行了表征。结果表明,合成的SBA-15分子筛孔径约为8 nm,粒径约为1 nm的Ru纳米粒子均匀分布在分子筛孔道中,添加适量的La2O3助剂可以显著提高催化剂的低温活性。当Ru和La2O3的负载量分别为4%和8%时,R4L8/SBA-15催化剂对CO转化率在255℃和265℃下分别达到56%和98%。     

Two-dimensional ruthenium nanoparticles between graphite layers: The effect of reduction temperature

A mixture of graphite powder and ruthenium chloride (III) anhydrous was treated at 723 K under 0.3 MPa chlorine for 3 days, followed by reduction under 40 kPa of hydrogen for 1 h to produce ruthenium metal particles intercalated between graphite layers (Ru-GIC). The structures of ruthenium particles depended on the reduction temperatures. Sheet-like ruthenium particles with 1–3 nm thickness and 10 to several hundred nm width containing numerous irregularly shaped holes with round edge, were formed by reduction at 573 K. A Ru-GIC sample treated at 653 K possessed two-dimensional ruthenium nanosheets with hexagonal holes (straight lines intersect at an angle of 120°) in a similar range of thickness and width. On the other hand, Ru-GIC samples reduced at 773 and 823 K showed two-dimensional plate morphology with a thickness of 1–4 nm. In addition, ruthenium nanoparticles supported on the graphite surface (Ru/Gmix) were also prepared from a slurry of ruthenium chloride (III) hydrate and graphite powder by impregnation and hydrogen reduction. The ruthenium particles in Ru/Gmix were spherical at about 3.6 nm, and the reduction temperature did not affect their particles size. Both Ru-GIC and Ru/Gmix samples were evaluated for cinnamaldehyde (CAL) hydrogenation in supercritical carbon dioxide solvent at 323 K, and they were active to produce cinnamyl alcohol (COL) and hydrocinnamaldehyde (HAL). However, Ru-GIC samples showed higher COL selectivity than Ru/Gmix prepared at the same reduction temperature, and COL selectivity over Ru-GIC increased with the reduction treatments at 773 and 823 K.     

Ru/ZrO2·xH2O催化喹啉加氢反应

制备了负载型催化剂Ru/ZrO2·xH2O, 并用XRD、XPS和TEM对催化剂进行了表征, 所制得的催化剂金属钌的平均粒径约为3.8 nm. 在2 MPa和40 ℃的温和条件下, 以水为溶剂时, Ru/ZrO2·xH2O催化喹啉加氢生成1,2,3,4-四氢喹啉的选择性达98.0%, 而且表现出较强的抗氮中毒能力, 催化剂循环使用性能稳定. 对喹啉加氢反应中的催化反应机理进行了探讨.