新型固定床Raney Ni催化剂的制备、表征及苯加氢活性评价

将镍铝合金粉、拟薄水铝石和田菁粉捏合、成型,在空气中高温焙烧,然后用苛性碱溶液充分浸取,制备出可应用于固定床加氢的活性Raney Ni催化剂.实验结果表明,成型合金焙烧过程中,富铝合金相逐渐转化为贫铝相,同时小部分金属铝氧化生成α-Al₂O₃,可提高催化剂的颗粒强度.BET和SEM分析表明,催化剂表面具有较宽的缝隙和丰富的大孔结构.苯加氢活性评价表明,在一定反应条件下,该新型固定床Raney Ni催化剂活性高于传统负载型镍催化剂,也高于按照专利方法制备的同类型催化剂.     

Raney Ni高效催化氯酚类污染物还原脱氯降解

采用Raney Ni催化剂,选择50%乙醇-水（50/50,体积比）作为溶剂体系,考察了不同类型碱及其添加量对Raney Ni催化4-氯苯酚（4-CP）还原脱氯反应的影响。结果表明,强碱（NaOH和KOH）和Et₃N更有利于Raney Ni催化下还原脱氯反应的进行,而且当n(NaOH/Et₃N)∶n(4-CP)=1.1~2.2时,Raney Ni能够保持较高的催化活性,可以在30min内实现4-CP的彻底还原脱氯,并建立了Raney Ni-50%乙醇-水（50/50,体积比）-NaOH催化体系。将该体系应用于研究取代基对Raney Ni催化芳香氯代物还原脱氯的影响,研究表明,Raney Ni催化剂对4-CP和4-氯苯胺（4-CA）的还原脱氯具有较高的选择性。进一步将Raney Ni-50%乙醇-水（50/50,体积比）-1.5NaOH催化体系应用于高浓度氯酚工业危废的还原脱氯处理,发现在该催化体系中氯酚工业危废中的氯代有机污染物可以彻底还原脱氯,且催化剂可以至少重复使用5次。该催化体系可以有效、彻底地还原脱氯降解氯酚工业危废,对高浓度氯酚工业危废的还原脱氯降解具有良好的应用前景。     

Mo改性Raney Ni催化加氢制备环己基多氟苯

以合金粉为原料,采用碱处理法,制备了Ni48.5Al48.5Mo3、Ni50Al50骤冷合金催化剂(RQ Ni-Mo、RQ Ni)和普通合金催化剂(Raney Ni-Mo、Raney Ni),通过ICP-AES、N2吸附脱附、XRD、H2-TPD和SEM对催化剂的物理化学性质进行了表征,将其应用于反-4-(2,3-二氟-4-甲基苯基)-4'-正丙基-1,1'-双环己基-3-烯(TF)催化加氢制备(反,反)-4-(2,3-二氟-4-甲基苯基)-4'-正丙基-1,1'-双环己烷(trans-TFT)的反应中并考察了其催化活性。结果表明:以Mo改性骤冷合金制备的RQ Ni-Mo催化剂具有较好的表观物性,比表面积为81.17 m2/g,孔容为0.12cm3/g,孔径为5.43nm、Ni晶粒尺寸为9.32 nm。在V(甲苯)=5 m L、m(RQ Ni-Mo)=0.05 g、m(TF)=0.20 g、反应温度40℃、反应压力1.5 MPa和反应时间2 h时,TF的转化率为100%,trans-TFT的选择性为69.72%。     

Y_2O_3含量对机械合金化Ni-20Cr-2.5Al合金热腐蚀行为的影响

采用机械合金化及热压法制备Ni-20 Cr-2.5Al、Ni-20 Cr-2.5 Al-0.8 Y2O3和Ni-20 Cr-2.5Al-3Y2O3高温合金,研究了不同含量Y2O3对Ni-20 Cr-2.5 Al合金在900℃空气中热腐蚀行为的影响。结果表明:Ni-20 Cr-2.5 Al合金在高温热腐蚀的实验初期有氧化膜剥落现象发生,而Ni-20 Cr-2.5 Al-0.8 Y2O3和Ni-20 Cr-2.5Al-3 Y2O3两种合金变化比较轻微;三种合金在氧化初期氧化增重比较明显,后期增重缓慢,涂有盐膜的Ni-20Cr-2.5Al合金的氧化增重最大,Ni-20Cr-0.8Y2O3合金次之,Ni-20Cr-2.5Al-3Y2O3合金的氧化增重最小。热腐蚀后三种合金表面的腐蚀膜分为两层,氧化膜外层主要由Al2O3组成,内层主要由靠近基体的Cr2O3组成,且Cr2O3腐蚀膜的厚度很薄。Y2O3的添加能够起到净化界面的作用,不仅提高了界面结合强度,也使得Al2O3保护膜具有更微小的晶粒,因而提高合金的抗热腐蚀性能。     

高强Cu-7Ni-3Al合金的制备及其在NaCl溶液中的耐蚀性

本文以铜镍系耐蚀铜合金为基础,利用真空熔炼法制备得到Cu-7Ni-3Al合金。通过静态浸泡法对Cu-7Ni-3Al在3.5%NaCl溶液中的腐蚀速度及腐蚀形态进行了研究。结果 表明,通过真空熔炼法能制备出综合力学性能良好的Cu-7Ni-3Al合金。在3.5%NaCl溶液中,Cu-7Ni-3Al合金耐腐蚀性能良好,这是因为在Cu-7Ni-3Al合金表面会生成Cu₂O,Al₂O₃和Cu₂(OH)₃Cl所组成的钝化层,该钝化层会抑制电化学反应的进行,从而达到提高合金耐腐蚀能力的效果。     

骨架镍催化剂的制备及其应用

骨架镍(Raney Ni)催化剂主要用于有机化合物的加氢和脱氢反应。从三十年代发展至今。因为它具有制备简便,机械强度高,催化活性好等优点,在有机化学工业中占着很重要的地位。一、催化剂的制备制备骨架镍的第一步是合金的制备,合金制备的好坏对催化剂的活性很有影响,其一是合     

铜改性镍基催化剂对联苯加氢的影响

用浸渍法制备了一系列金属负载型催化剂,用于联苯催化加氢制备环己基苯（CHB)。侧重考察了Cu改性的Ni基催化剂Ni-Cu/Al2O3的催化性能,并用X射线粉末衍射(XRD)、氮气吸附脱附(BET)、扫描电子显微镜（SEM）及透射电子显微镜（TEM）对催化剂进行表征。研究发现,50%(ω)Ni-10%Cu(ω)/Al2O3中,Cu晶粒在催化剂表面优先析出,使表面Ni活性中心稀释、Ni晶粒变小,从而提高CHB的选择性。结果表明：在环己烷溶剂中、50%(ω)Ni-10%Cu(ω)/Al2O3催化作用下、于2.2MPa H2、200℃反应4h,联苯的转化率可达94.7%,CHB的选择性达到99.8%。催化剂循环使用10次后,联苯的转化率稍有降低,CHB的选择性几乎不变。     

NaCl和KClO_3含量对盐助燃烧合成的NiTi粉体组成和结构的影响

盐助燃烧合成制备了不同Na Cl和KCl O3含量的Ni Ti合金粉末,采用XRD、SEM和EDS等方法对Ni Ti合金的组成和结构进行表征,并分析了不同Na Cl和KCl O3含量对Ni Ti粉体组成和结构的影响及其作用机制。结果表明,随Na Cl含量的增加,Ni Ti、Ni4Ti3相组成比例发生不同的变化,其中10%(wt)Na Cl中Ni Ti相含量最高为92%。随KCl O3含量的增加,粉体中Ni4Ti3和Ti O2的含量大幅增加,5%(wt)KCl O3中Ni、Ti原子比最佳为0.79:1。粉碎后的Ni Ti粉末,具有形状不一的颗粒形貌和较宽的粒度分布范围。不同Na Cl含量的粉末粒度基本保持不变,在950 nm左右,而不同KCl O3含量的Ni Ti材料的平均粒度随其含量的增加而减小。     

催化还原制备3-氯-4-甲基苯胺的研究进展

综述了卤代硝基苯还原为相应苯胺的方法,并对这些方法进行了简要的评论。指出催化制备3-氯-4-甲基苯胺的最佳方法是以Raney Ni为催化剂,有机胺为脱卤抑制剂的液相加氢法。     

Ni-Mn/Al_2O_3催化剂在浆态床中CO甲烷化催化性能

采用共浸渍法制备了Ni-Mn/Al2O3催化剂,考察了助剂Mn的含量对催化剂结构及浆态床CO甲烷化性能的影响。采用XRD、H2-TPR、BET、TEM、H2-化学吸附等表征对催化剂进行了测试分析,结果表明,Mn助剂的引入能够促进Ni物种在载体表面的分散,减弱Ni物种与载体的相互作用,降低催化剂的还原温度,提高催化剂的比表面积,减小活性金属Ni的晶粒尺寸。随着Mn含量的增加,Ni-Mn/Al2O3催化剂的甲烷化性能先升后降,其中以Mn含量为4%(质量分数)时的催化甲烷化性能最佳,添加过量的Mn导致活性组分Ni被部分覆盖,催化甲烷化性能下降。通过对16Ni4Mn/Al2O3催化剂样品的浆态床反应温度及反应压力的研究发现,当反应温度为280℃、反应压力为1.5 MPa时,催化剂样品16Ni4Mn/Al2O3的CO转化率及CH4选择性分别达到96.2%和88.8%。     

Electrochemical behaviour of Ni + Al alloy as an alternative material for molten carbonate fuel cell cathodes

This paper presents an investigation of the performance and stability for oxygen reduction on in situ oxidized Ni alloys, specially focused on 95 at % Ni + 5 at % Al and 85 at % Ni + 15 at % Al alloy electrodes in Li/Na carbonate eutectic. Test specimens of the alloys were prepared as thin film electrodes sputtered onto Au substrates. In situ oxidation of alloy electrodes and electrochemical measurements for oxygen reduction on the electrodes were performed in the free-volume melt at 923 K. It was found that the in situ oxidized Ni + Al alloys exhibit higher performance for the oxygen reduction than the NiO without Al. Electrochemical fractal analysis (EFA) revealed higher oxide film stability of the Ni + Al alloys in comparison to NiO electrodes. The surface morphology of the alloy specimen after oxidation was investigated with SEM and AFM.     

高效雷尼镍催化1,4-丁炔二醇加氢制备1,4-丁二醇

通过控制加热电流强度的方法,制备了不同Ni2Al3质量分数的镍铝合金。选取高Ni2Al3质量分数的合金进行预刻蚀和二次刻蚀处理,得到两种颗粒状雷尼镍催化剂,并用于1,4-丁炔二醇（BYD）加氢制1,4-丁二醇（BDO）。结果表明,二次刻蚀法得到的雷尼镍催化BYD加氢,在140℃、5MPa压力下反应1 h,转化率可达100%,BDO收率92%;而预刻蚀雷尼镍达到相同BDO收率所需时间为3 h。采用ICP、BET、XRD、XPS、SEM等方法对催化剂进行了表征,结果表明：二次刻蚀相较预刻蚀得到的催化剂比表面积更大,达到12.83 m2/g;并且表面微观结构更粗糙,富含缺陷活性位,Ni元素质量分数达到了61.45%。此外,金属Ni的分散性提高,表面金属Al完全消失,而Al和Ni的氧化物增多,这使得催化剂表面的骨架结构更加稳定,显著提高了催化剂的催化活性。     

溅射Ni11Co26Cr6Al0.5Y涂层对镍基合金在900℃腐蚀行为的影响

采用真空溅射技术在镍基合金表面沉积Ni11Co26Cr6Al0.5Y纳米晶涂层,研究有、无涂层合金在900℃的75%Na_2SO_4+25%K_2SO_4熔融混合硫酸盐膜中的热腐蚀行为。结果表明:无涂层合金发生腐蚀,生成内氧化物和内硫化物。而Ni11Co26Cr6Al0.5Y涂层在热腐蚀过程中,表面生成Al_2O_3、NiCr_2O_4、Cr_2O_3和NiO氧化膜,仅在近涂层与基体界面区域存在少量Al_2O_3内氧化物。     

Raney Ni catalysts derived from different alloy precursors (I) morphology and characterization

Ni-Al alloys containing 41.3, 49.2 and 59.9 wt% Ni were leached by reaction with 20 wt% aqueous NaOH solution under different temperature and time. The reactivities of alloys and morphologies of resultant catalysts were investigated. A large difference in reactivities of alloys toward alkali solution was revealed according to the composition of the alloy. As Al content in precursor alloy increased, the reactivity of alloy toward alkali solution increased. It was shown that, during leaching, reaction in Ni 41.3 wt% alloy is restricted to reaction interface, whereas that in Ni 49.9 wt% alloy occurs throughout the product layer. Surface area and pore size distribution were seen to be strongly dependent upon leaching conditions and relatively independent of the composition of precursor alloy. This paper was prepared at the 2004 Korea/Japan/Taiwan Chemical Engineering Conference held at Busan, Korea between November 3 and 4, 2004.     

Skeletal Ni catalysts prepared from Ni–Al alloys rapidly quenched at different rates: Texture,structure and catalytic performance in chemoselective hydrogenation of 2-ethylanthraquinone

Skeletal Ni catalysts (RQ Ni) prepared by alkali leaching of rapidly quenched Ni–Al alloys have been systematically characterized, focusing on the effect of the cooling rate during alloy preparation. It is found that the residual Al content, texture, structure, surface hydrogen species, and active sites of the RQ Ni catalysts can be controlled by the cooling rate of the Ni–Al alloys. In liquid-phase hydrogenation of 2-ethylanthraquinone (eAQ), the RQ Ni catalyst with higher cooling rate favors hydrogenation of the carbonyl group and retards the saturation of the aromatic ring and the formation of the degradation products, thus leading to a higher yield of H₂O₂. Based on the characterizations, the improved selectivity is ascribed to the dominant population of strongly chemisorbed hydrogen, which is inactive for the hydrogenation of the aromatic ring, along with the electronic interaction between residual metallic Al and Ni, favoring a carbonyl group-bonded configuration of eAQ on the catalyst.     

纳米镍基催化剂母合金的快速凝固过程微观结构研究

为了获得高效、环境友好的纳米微晶骨架镍催化材料,采用电弧感应重熔技术以及快速凝固技术制备了纳米微晶的NiAl母合金条带,并通过XRD、SEM等分析技术揭示了NiAl合金快速凝固过程的相组成以及显微结构变化规律。研究表明,在合金成分一定时,快淬的冷却速率对合金的相组成、相对含量以及微观结构有着重要的影响,考虑到加工条件,通常以30 m·s－1为佳,此时合金中有效相Al3Ni2相对含量达到最大,晶粒细小,部分非晶化。     

Interface microstructure and mechanical properties of Ni–Co–P alloy coatings modified carbon fibres reinforced 7075Al matrix composites

To optimize interface microstructure between 7075Al matrix and CFs, Ni–Co–P multi-component alloy coatings coated carbon fibres were prepared by electroless plating firstly and then Ni–Co–P coated CFs reinforced 7075Al matrix composites (CF/Al(Ni–Co–P)) with high relative density were fabricated by hot pressing sintering process. After modification of Ni–Co–P coatings, Al–Co–Ni Intermetallic compounds were formed stably between matrix and reinforcement because of the smaller mixing enthalpy values of Al–Co, Al–Ni and Co–Ni, which not only restrained the generation of Al₄C₃ but also improved interfacial bonding strength. Yield strength and ultimate tensile strength of CF/Al(Ni–Co–P) composites with 30 vol% CFs had maximum improvement compared with CF/Al(U) composites than other composites reinforced by 10 vol%, 20 vol% and 30 vol%CFs, which is up to 305.8 MPa and 668.7 MPa respectively, and the fracture mode of composites from accumulation fracture to non-accumulation fracture as the existence of Ni–Co–P coatings.     

The effect of vacuum evaporation plating on phase structure and electrochemical properties of AB5–5 mass% LaMg3 composite alloy

In this paper, Cu, Al and Ni were plated on the AB₅–5 mass% LaMg₃ composite hydrogen storage alloy using a vacuum evaporation plating method. The phase structure and the electrochemical properties were investigated. The X-ray diffraction (XRD) analysis shows that the phase structure is not changed obviously after the plating Cu, Al and Ni on the composites. The electrochemical tests show that maximum discharge capacity, high rate dischargeability (HRD), dischargeability at low temperature and cyclic stability was improved by vacuum evaporation plating Cu, Al and Ni. Maximum of discharge capacity of the AB₅–5 mass% LaMg₃ composite alloy plating Ni can reach 351 mAh/g, which is 3.5% higher than that of the untreated. HRD at I_d = 1200 mA/g of the composite alloy plating Cu is 45.0% of that at 60 mA/g, which is 20.4% higher than the untreated. Discharge capacity of the composite alloy plating Cu at low temperature 233 K is 205 mAh/g, which is 57.3% of that at 298 K, and it is much higher than 36.8% of the untreated composites. The discharge capacity retention of the composite alloy plating Al after 200 cycles is 7.8% higher than the untreated.     

TiO2-Pt/Mm（Ni3.4Mn0.4Al0.3Co0.7）电极的可助光充电

1～8 nm的Pt微粒通过光催化分解法沉积在20～50 nm的TiO₂微粒表面,然后把所制备的TiO₂-Pt纳米微粒修饰到富La的贮氢合金电极的表面,形成可助光充电的TiO₂-Pt/Mm（Ni_3.4Mn_0.4Al_0.3Co_0.7）电极（TPM电极）,研究了TPM电极的光电化学、可助光充电行为。结果表明：微小的电流对TPM电极的光充电效应有较强的辅助作用。当TPM电极只被光照时,放出的电量较小;而在光照的同时加上一个微弱的电流,可显著改善其光充电性能。通过交流阻抗谱和循环伏安实验研究了其光充电机理。     

Al2O3-ZrO2负载Ni2P催化剂加氢脱硫脱氮活性

采用浸渍-沉淀法制备Al2O3-ZrO2复合氧化物,通过程序升温还原法制备Ni2P/Al2O3-ZrO2催化剂。运用X射线衍射、N2吸附-脱附、X射线光电子能谱技术对载体和催化剂进行表征,并以噻吩加氢脱硫、吡啶加氢脱氮反应为探针考察复合氧化物对Ni2P催化剂加氢活性的影响。结果表明,在Al2O3表面引入少量ZrO2,既保持了γ-Al2O3大比表面积的结构优势,又减少了P或Ni与Al2O3表面的接触,促进Ni2P的形成。载体中ZrO2质量分数20%的Ni2P/Al2O3-ZrO2催化剂活性最高,载体焙烧温度过高会导致催化剂活性下降。