Pt nanoparticles entrapped in ordered mesoporous carbons:An efficient catalyst for the liquid-phase hydrogenation of nitrobenzene and its derivatives

Pt nanoparticles entrapped in ordered mesoporous CMK-3 carbons with p6mm symmetry were prepared using a facile impregnation method, and the resulting materials were characterized using X-ray diffraction spectroscopy, N2 adsorption-desorption, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The Pt nanoparticles were highly dispersed in the CMK-3 with 43.7% dispersion. The Pt/CMK-3 catalyst was an effective catalyst for the liquid-phase hydrogenation of nitrobenzene and its derivatives under the experimental conditions studied here. The Pt/CMK-3 catalyst was more active than commercial Pt/C catalyst in most cases. A highest turnover frequency of 43.8 s-1 was measured when the Pt/CMK-3 catalyst was applied for the hydrogenation of 2-methyl-nitrobenzene in ethanol under optimal conditions. It is worthy of note that the Pt/CMK-3 catalyst could be recycled easily, and could be reused at least fourteen times without any loss in activity or selectivity for the hydrogenation of nitrobenzene in ethanol.

Kinetics of Liquid-Phase Hydrogenation of Toluene Catalyzed by Hydrogen Storage Alloy MlNi_5

The kinetics of liquid-phase hydrogenation of toluene catalyzed by MlNi_5 was studied by investigating the influences of the reaction temperature and pressure on the mass transfer-reaction processes inside the slurry. The results show that the reaction rate accelerates when the reaction temperature increases, and reaches its maximum at about 490 K, but if temperature is higher than 510 K, the reaction rate decreases rapidly. The whole reaction process is controlled by the reaction at the surface of the catalyst particles. The mass transfer resistance at gas-liquid interface and that from the bulk liquid phase to the surface of the catalyst particle can be neglected. The apparent reaction rate is zero order for toluene concentration and first order for hydrogen concentration in the liquid phase. The kinetic model is obtained. The kinetic model fits the experimental data very well. The apparent activation energy of the hydrogen absorption reaction of MlNi_5-toluene slurry system is 41.01 kJ·mol^(-1).

Computational Fluid Dynamics Simulation of Liquid-Phase FCC Diesel Hydrotreating in Tubular Reactor

The computational fluid dynamics(CFD) code, FLUENT, was used to simulate the liquid-phase FCC diesel hydrotreating tubular reactor with a ceramic membrane tube dispenser. The chemical reaction and reaction heat were added to the model by user-defined function(UDF), showing the distribution of temperature and content of sulfides, nitrides, bicyclic aromatics and monocyclic aromatics in different parts of the reaction bed. When the pressure was 6.5 MPa, the amount of mixing hydrogen was 0.84%(m), the space velocity was 2 h-1 and the inlet temperature was 633 K, the temperature reached a maximum at a height of 0.15 m, and the range of radial temperature reached its maximum(2.5 K) at a height of 0.15 m. It indicated that the proper ratio of height to diameter of catalyst bed in the tubular reactor was 5-6. The increase of inlet temperature, the mixing hydrogen and the decrease of space velocity led to the decrease in the content of bicyclic aromatics, sulfides and nitrides, and the increase in monocyclic aromatics content, while the high temperature increased. The results were in good agreement with experimental data, indicating to the high accuracy of the model.

Palladium nanoclusters immobilized on defective nanodiamond-graphene core-shell supports for semihydrogenation of phenylacetylene

We report a nanocarbon material with nanodiamond(ND) core and graphene shell(ND@G) as a support for Pd nanocatalysts. The designed catalyst performed good selectivity of styrene(85.2%) at full conversion of phenylacetylene and superior stability under mild conditions. Supported Pd catalysts are characterized by means of high resolution transmission electron microscopy(HRTEM), Raman, X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS) and H2 temperature-programmed reduction(H2-TPR).The results clearly show that formation of the strong metal-support interaction(SMSI) between Pd nanoclusters and the defective graphene shell helpfully modifies the selectivity and stability of the Pd-based catalysts.

Self-assembly synthesis of phosphorus-doped tubular g-C_(3)N_(4);Ti_(3)C_(2)MXene Schottky junction for boosting photocatalytic hydrogen evolution

Establishing highly effective charge transfer channels in carbon nitride(g-C_(3)N_(4)) to enhance its photocatalytic activity is still a challenging issue.Herein,the delaminated 2D Ti_(3)C_(2) MXene nanosheets were employed to decorate the P-doped tubular g-C_(3)N_(4)(PTCN)for engineering 1D/2D Schottky heterojunction(PTCN/TC)through electrostatic self-assembly.The optimized PTCN/TC exhibited the highest hydrogen evolution rate(565 μmol h^(-1)g^(-1)),which was 4.3 and 2.0-fold higher than pristine bulk g-C_(3)N_(4) and PTCN,respectively.Such enhancement may be primarily attributed to the phosphorus heteroatom doped and unique structure of 1D/2D g-C_(3)N_(4)/Ti_(3)C_(2) Schottky heterojunction,enhancing the light-harvesting and charges’separation.One-dimensional pathway of g-C_(3)N_(4) tube and built-in electric field of interfacial Schottky effect can significantly facilitate the spatial separation of photogenerated charge carriers,and simultaneously inhibit their recombination via Schottky barrier.In this composite,metallic Ti_(3)C_(2) was served as electrons sink and photons collector.Moreover,ultrathin Ti_(3)C_(2) flake with exposed terminal metal sites as a co-catalyst exhibited higher photocatalytic reactivity in H2 evolution compared to carbon materials(such as reduced graphene oxide).This work not only proposed the mechanism of tubular g-C_(3)N_(4)/Ti_(3)C_(2) Schottky junction in photocatalysis,but also provided a feasible way to load ultrathin Ti_(3)C_(2) as a co-catalyst for designing highly efficient photocatalysts.

A Hydrogen-bonded Tubular Structure of Zinc(Ⅱ) and Methyl-3-pyridylcarbamate

A zinc（Ⅱ） compound [ZnCl2（mpcm）2]（1,mpcm = methyl-3-pyridylcarbamate） was prepared by solvothermal reaction and characterized by elemental analysis,IR spectroscopy,TGA and single-crystal X-ray diffraction.The crystal is of monoclinic system,space group P21/n,C14H16ZnCl2N4O4,Mr = 440.58,a = 8.7893（7）,b = 24.978（2）,c = 9.2510（8）,β = 109.318（1）°,V = 1916.6（3）3,Z = 4,θ = 1.63～25.20°,Dc = 1.527 g/cm3,μ = 1.585 mm-1,F（000） = 896,the final R = 0.0255 and wR = 0.0654 for 3080 observed reflections with Ⅰ 〉 2σ（Ⅰ）.The zinc atom is four-coordinated by the pyridyl groups of two mpcm ligands and two chloride ions with a tetrahedral geometry.Two [ZnCl2（mpcm）2] subunits are held together by a pair of hydrogen bonds,forming a 32-membered macrocyclic dimer,which is further extended into a 3D tubular structure via hydrogen bonding.

Hydrogenation of CO_(2) to p-xylene over ZnZrO_(x)/hollow tubular HZSM-5 tandem catalyst

The conversion of CO_(2) into specific aromatics by modulating the morphology of zeolites is a promising strategy.HZSM-5 zeolite with hollow tubular morphology is reported.The morphology of zeolite was precisely controlled,and the acid sites on its outer surface were passivated by steam-assisted crystallization method,so that the zeolite exhibits higher aromatic selectivity than sheet HZSM-5 zeolite and greater p-xylene selectivity than chain HZSM-5 zeolite.The tandem catalyst was formed by combining hollow tubular HZSM-5 zeolites with ZnZrO_(x)metal oxides.The para-selectivity of p-xylene reached 76.2%at reaction temperature of 320℃,pressure of 3.0 MPa,and a flow rate of 2400 mL g^(-1)h^(-1)with an H_(2)/CO_(2) molar ratio of 3/1.Further research indicates that the high selectivity of p-xylene is due to the pore structure of hollow tubular HZSM-5 zeolite,which is conducive to the formation of p-xylene.Moreover,the passivation of the acid site located on the outer surface of zeolite effectively prevents the isomerization of p-xylene.The reaction mechanism of CO_(2) hydrogenation over the tandem catalyst was investigated using in-situ diffuse reflectance Fourier transform infrared spectroscopy and density functional theory.The results showed that the CO_(2) to p-xylene followed a methanol-mediated route over ZnZrO_(x)/hollow tubular HZSM-5 tandem catalysts.In addition,the catalyst showed no significant deactivation in the 100 h stability test.This present study provides an effective strategy for the design of catalysts aimed at selectively preparing aromatics through CO_(2)hydrogenation.

Sulfonate group modified Ni catalyst for highly efficient liquid-phase selective hydrogenation of bio-derived furfural

The liquid-phase furfural （FAL） hydrogenation to furfuryl alcohol （FOL） and tetrahydrofurfuryl alcohol （THFOL） was investigated using sulfonate group （-SO3H） grafted activated carbon （AC） supported Ni catalyst, which was prepared and activated simultaneously by liquid phase reduction method. This functionalized nickel catalyst demonstrated an enhanced catalytic performance for selective hydrogenation of FAL, in which almost 100% FOL （〈80℃） and THFOL （〉100℃） selectivity with complete conversion was obtained, respectively. More importantly, the conversion of transfer hydrogenation of FAL to FOL also can reach almost 100% under optimal conditions （140℃, 4.0h）. The effect of -SO3H was evaluated and systematically analyzed by the combination of reaction performance and physico-chemical characterizations. Cycling test proved the prepared catalyst could be recycled and reused for several times without noticeably reducing catalytic activity of hvdrogenation.

Performance of a tubular oxygen-permeable membrane reactor for partial oxidation of CH_4 in coke oven gas to syngas

A gas-tight BaCo 0.7 Fe 0.2 Nb 0.1 O 3-δ（BCFNO） tubular membrane was fabricated by hot pressure casting.And a membrane reactor with BCFNO tubular membrane and Ag-based sealant was readily constructed and applied to partial oxidation of CH4 in coke oven gas.At 875 ℃,95% of methane conversion,91% of H 2 and as high as 10 ml cm-2·min-1 of oxygen permeation flux were obtained.There was a good match in the coefficient of thermal expansion between Ag-based alloy and BCFNO membrane materials.The tubular BCFNO membrane reactor packed with Ni-based catalysts exhibited not only high activity but also good stability in hydrogen-enriched coke oven gas（COG） atmosphere.

Hydrogen Separation Using Pt-Alumina Impregnated Membrane

A tubular commercial mesoporous support was used to prepare a Pt impregnated membrane using the reservoir method and tested for moderate temperature (300°C) gas transport of hydrogen (H2), helium (He) and nitrogen (N2) gas molecules. H2 and N2 gas permeation of 6.1 and 4.5 l/min at 1.0 barg feed pressure and 25°C respectively was obtained from the support. On the other hand, H2 and N2 gas permeation of 4.6 and 1.7 l/min at 1.0 barg feed pressure and 25°C respectively was also obtained from the Pt membrane. Selectivity of H2 over He of 1.96 at 300°C and 1.6 barg for the Pt membrane was obtained and found to be higher than that of the theoretical Knudsen selectivity. Also, a selectivity of H2 over N2 of 2.72 at 25°C and 1.0 barg was obtained and found to be close to that of the theoretical Knudsen selectivity. The gas permeation and the selectivity performance of the membrane were evaluated.

便携式装置中双凸台取电微管式固体氧化物燃料电池数值模拟及实验验证

本工作利用甲醇水蒸气重整制氢和管式固体氧化物燃料电池的各自优势,设计了一种甲醇水蒸气重整制氢(MSR)耦合微管式固体氧化物燃料电池(μT-SOFC)便携式制氢发电装置。使用COMSOL Multiphysics有限元仿真软件建立双凸台取电的μT-SOFC数学模型并验证模型(误差率小于5%)。仿真结果表明双凸台取电方式可高效地收集电流,不同电压下电池整体具有较小的温度差。MSR催化剂和阳极支撑型μT-SOFC分别使用浸渍法和挤出成型-浸浆工艺制备。借助场发射扫描电子显微镜和能谱分析技术表征MSR催化剂和μT-SOFC材料特性。借助气相色谱仪分析MSR产物气体成分,分析得到氢气体积分数接近70%。便携式装置使用步进电机控制甲醇水溶液进液流量,可获得不同的MSR气体产物体积流量,平均最高可达1163 mL/min。应用于装置中的μT-SOFC开路电压为0.96 V,最大输出功率密度为190 mW/cm~2。电池在模拟实际使用4小时后,其电化学性能基本没有发生衰减。同时对此工况下的电池进行仿真,仿真结果表明,电池性能主要受MSR转化效率的限制,改变空气进气方向可提高电池输出功率。目前关于微管式燃料电池及其设备的应用研究甚少,本工作对μT-SOFC在便携式装置中的应用具有指导作用。

胡萝卜苷对H_(2)O_(2)诱导的HK-2细胞氧化应激的保护作用研究

目的分析胡萝卜苷干预对过氧化氢(H_(2)O_(2))诱导的人肾小管上皮细胞(HK-2细胞)氧化应激的保护作用及作用机制。方法体外培养HK-2细胞,对照组加入等体积0.9%氯化钠溶液,实验组中加入不同浓度的H_(2)O_(2)处理24h(1、5、10、50和100μmol/L),干预组中加入50μmol/L胡萝卜苷干预2h后再加入不同浓度H_(2)O_(2)处理,CCK-8实验检测各组细胞活力;Hochest33342/PI荧光染色和caspase-3免疫荧光实验分析各组细胞凋亡;DCFH-DA荧光探针染色分析各组细胞中的活性氧簇(reactive oxygen species,ROS)水平;Western blot法检测各组细胞中Bax、Bcl-2和NOX4蛋白的表达水平。结果50μmol/L和10μmol/L H_(2)O_(2)处理后实验组中的抑制率分别为20.74%±3.32%和53.90%±2.37%,胡萝卜苷干预组中各抑制率分别为10.29%±1.69%(t=4.859,P=0.008)和37.38%±3.95%(t=6.212,P=0.003),差异均有统计学意义;Hochest33342/PI荧光染色结果显示,实验组中Hochest33342荧光信号聚集细胞以及PI荧光阳性细胞明显多于干预组;免疫荧光实验结果显示实验组中caspase-3表达水平明显高于干预组;荧光探针染色结果显示实验组中ROS水平明显高于干预组;Western blot法结果显示,H_(2)O_(2)实验组中NOX4蛋白表达水平高于对照组,经干预后出现明显下调,干预组中Bax蛋白表达水平也低于H_(2)O_(2)实验组。结论胡萝卜苷干预可减轻H_(2)O_(2)诱导的HK-2细胞氧化应激,并降低细胞凋亡发挥保护作用。

硫酸盐还原菌的腐蚀机理

采用硫酸盐还原菌 ( SRB)培养技术 ,研究了 SRB的生长特性 ,结果表明 :在 SRB的整个生长过程中 ,培养液中 SO2 -4 浓度逐渐减小 ;但当 SRB处于繁殖期时 ,H2 S释放量逐渐增大 ;处于衰亡期时 ,H2 S释放量逐渐减小。同时 ,对三种油田管材进行浸泡试验 ,采用扫描电镜对试样腐蚀产物形貌及组成进行分析 ,发现腐蚀产物主要为 Fe S和 Fe1-x S。着重研究了 SRB的腐蚀机理 ,结果表明 :SRB的代谢产物 ,特别是 H2 S,是加快腐蚀的主要原因 ,它们对腐蚀反应即有阴极去极化作用 ,又有阳极去极化作用。

催化裂化柴油管式液相加氢的实验研究

采用管式反应器实验装置进行催化裂化柴油（LCO）液相加氢反应。在单反应管模式下,考察了反应压力、混氢量、空速、温度对加氢反应的影响及混氢量对催化剂床层热点温度的影响;在双反应管串联模式（中间补氢）下,考察了不同混氢量对加氢反应的影响。结果表明,单反应管催化裂化柴油液相加氢反应较为适宜的条件为压力6.5 MPa、混氢量（质量分数）0.56%、空速2.0h-1、温度360℃;管式反应器液相加氢的催化剂床层热点温差在10~20℃之间,热点温度出现在床层高度的15%~30%范围,最为合适的补氢点应在热点温度高峰出现下落趋势处。采用双反应管串联装置进行催化裂化柴油液相加氢反应,可使脱硫率、脱氮率均达到90%以上。

高含H_2S环境中CO_2对P110套管钢氢脆腐蚀行为的影响

通过溶液浸泡、恒载荷硫化物应力腐蚀开裂(SSC)、电化学氢渗透等实验方法分别分析API-P110套管钢在高含50%H2S和50%CO2的酸性溶液中和在高含50%H2S酸性溶液中氢脆腐蚀行为,探讨了CO2对套管钢氢脆腐蚀行为的影响。与未经过腐蚀试样相比,在H2S与CO2共存环境中和在H2S腐蚀环境中P110套管钢的强度(抗拉强度(bσ)和屈服强度(sσ))和延伸率(δ)下降,发生晶间断裂。与单一H2S环境相比,在H2S和CO2共存环境中钢的强度和延伸率下降程度较小、脆化率小、SSC敏感性低、氢渗透速率(J)小。在不同腐蚀环境中钢的氢渗透电流密度(J)都呈现随时间(t)延长急剧增加到峰值,然后缓慢下降直到出现稳态。在高含H2S腐蚀环境中,CO2提高了腐蚀产物膜的致密性,降低了膜中FexSy含量,减少了钢的氢原子渗透量,从而降低钢的氢脆敏感性。

油井管钢氢致开裂门槛值研究

四种高强度油并管钢动态充氢时，进入试样的可扩散氢含量c0和充氢电流i成正比；而氢致断裂门槛应力σc与名义屈服强度σt之比和Inc0成正比，即σc／σt=A-BInc0．测量了四种钢在H2S中浸泡时进入试样的c0，求出相应的ic，用ic充氢时测出的门槛应力σc（H）／σt和H2S中应力腐蚀门槛应力σc（H2S）／σt相一致这表明，可用特定电流下的动态充氢来代替H2S应力腐蚀．

肾小管细胞氧化性损伤模型的建立

目的 建立过氧化氢 (H2 O2 )所致肾小管氧化性损伤模型。方法 利用离体培养肾小管细胞建立氧化性损伤模型 ,观察肾小管细胞形态结构的改变及细胞存活率、乳酸脱氢酶 (lactateddehydrogenase ,LDH)释放率、脂质过氧化产物丙二醛 (malondialde hyde,MDA)含量的变化 ,以及还原型谷胱甘肽的保护作用。结果 H2 O2 所致肾小管细胞损伤 ,表现为细胞存活率降低 ,LDH释放增加和MDA含量增加。还原型谷胱甘肽能提高细胞存活率 ,降低LDH释放 ,减轻脂质过氧化反应。结论 H2 O2 可复制离体肾小管氧化性损伤模型 ,还原型谷胱甘肽对损伤的肾小管上皮细胞有保护作用。

石油管材的氢致裂纹与滞后断裂

氢致裂纹和滞后断裂是石油管材的主要失效形式之一。论述了石油管材的氢致裂纹和氢致滞后断裂（应力腐蚀）的区别和联系，重点讨论了石油管材在H2S中产生氢致裂纹的特征和条件，以及钢中非金属夹杂物、化学成分、组织结构等对氢致裂纹的影响。同时，讨论了石油钻具氢致滞后断裂的特点；提出了预防氢致开裂和氢致应力腐蚀的若干措施。

抗硫膨胀管力学性能及膨胀动力性能研究

为解决高含硫气田开发后期可能出现的套管漏失及腐蚀穿孔问题,优选了抗硫膨胀管材质,采用试验分析方法,研究了抗硫膨胀管膨胀前后力学性能变化及套管环空条件下腐蚀后的力学性能损伤。研究结果表明,膨胀管材质膨胀后与膨胀前相比,屈服强度提高了64.7%,抗拉强度提高了20.2%,伸长率降低了31.9%,能够满足膨胀管的使用性能要求。膨胀管腐蚀后仍保持较好的塑性性能和冲击韧性,其中腐蚀后膨胀管屈服强度增加了14.8%,抗拉强度提高了1.8%,伸长率增长了3.9%,冲击功提高了10.6%,冲击韧度提高了10.5%。在此基础上设计了膨胀管膨胀系统,试验分析了膨胀系统膨胀动力性能,得出了膨胀管膨胀系统启动运行压力,验证了膨胀系统运行的可靠性。所得研究结果可为高含硫气田的高效开发提供技术储备。

硫化氢对TGF-β1诱导的HK-2细胞上皮间充质转化的抑制作用

目的:观察硫化氢(H2S)对转化生长因子-β1(TGF-β1)诱导的人近端肾小管上皮细胞转分化的影响,并初步探讨其作用的可能机制。方法:以体外培养的HK-2细胞为研究对象,分别用10μg/LTGF-β1、100μmol/LNaHS(H2S的供体)及2者联合作用进行干预,以正常培养的细胞作正常对照。孵育0、15、30及60min后,Westernblot检测4组细胞磷酸化Smad2/3(p-Smad2/3)和Smad2蛋白的表达;孵育48h后,观察细胞形态变化,Westernblot检测4组细胞E-cadherin、α-SMA蛋白的表达。结果:与正常对照组比较,TGF-β1组细胞发生梭形变,E-cadherin蛋白表达下降(F=1262.535,P<0.001),α-SMA蛋白表达上调(F=1456.030,P<0.001);NaHS+TGF-β1组细胞发生梭形变的程度较TGF-β1组明显减轻,E-cadherin蛋白表达增加(F=65.330,P<0.001),α-SMA蛋白表达下降(F=288.300,P<0.001)。TGF-β1组细胞在15、30及60min时p-Smad2/3表达均较正常对照组增加,而NaHS+TGF-β1组细胞p-Smad2/3的表达较TGF-β1组降低(P<0.05)。结论:H2S可抑制TGF-β1诱导的HK-2细胞转分化,该作用可能部分通过影响Smad2/3磷酸化程度来完成。