Ni-Fe-B合金沉积对碳纤维毡石墨化的影响

为研究Ni-Fe-B合金对碳纤维毡催化石墨化的影响,采用电沉积的方法,通过改变电解液中FeSO_4·7H_(2)O的质量浓度,实现Ni-Fe-B合金层在碳纤维毡上均匀负载,并探讨Ni-Fe-B合金对碳纤维毡石墨化程度的影响。结果表明,在FeSO_4·7H_(2)O质量浓度100 g/L、温度50℃、电流1 A/dm^(2)、沉积3 min的条件下进行电沉积,高温处理后负载的碳纤维毡石墨化率可高达90.77%,表面电阻率从1.99 mΩ·cm降到0.82 mΩ·cm,降低了58.69%。研究发现,在2400℃的高温下,Ni-Fe-B合金对碳纤维毡能起到催化石墨化作用,将无序结构的碳纤维成功转化为有序结构的石墨纤维。

High-performance solar vapor generation of Ni/carbon nanomaterials by controlled carbonization of waste polypropylene

Solar vapor generation is emerging as a promising technology using solar energy for various applications including desalination and freshwater production.However,from the viewpoints of industrial and academic research,it remains challenging to prepare low-cost and high-efficiency photothermal materials.In this work,we report the controlled carbonization of polypropylene(PP)using NiO and poly(ionic liquid)(PIL)as combined catalysts to prepare a Ni/carbon nanomaterial(Ni/CNM).The morphology and textural property of Ni/CNM are modulated by adding a trace amount of PIL.Ni/CNM consists of cup-stacked carbon nanotubes(CS-CNTs)and pear-shaped metallic Ni nanoparticles.Due to the synergistic effect of Ni and CS-CNTs in solar absorption,Ni/CNM possesses an excellent property of photothermal conversion.Meanwhile,Ni/CNM with a high specific surface area and rich micro-/meso-/macropores constructs a threedimensional(3 D)porous network for efficient water supply and vapor channels.Thanks to high solar absorption,fast water transport,and low thermal conductivity,Ni/CNM exhibits a high water evaporation rate of 1.67 kg m^-2 h^-1,a solar-to-vapor conversion efficiency of 94.9%,and an excellent stability for 10 cycles.It also works well when converting dyecontaining water,seawater,and oil/water emulsion into healthy drinkable water.The metallic ion removal efficiency of seawater is 99.99%,and the dye removal efficiency is>99.9%.More importantly,it prevails over the-state-of-art carbonbased photothermal materials in solar energy-driven vapor generation.This work not only proposes a new sustainable approach to convert waste polymers into advanced metal/carbon hybrids,but also contributes to the fields of solar energy utilization and seawater desalination.

碳笼负载镍基磁性催化剂Ni@Cage-C的制备与性能研究

以自然结晶法制备的ZIF-67为前驱体,采用包裹-刻蚀-碳化策略,得到大小均匀的纳米碳笼(Cage-C),再于液相条件下以碳笼为载体负载上活性金属镍(Ni),成功制备了非贵金属磁性催化剂Ni@Cage-C,并应用于对硝基苯酚催化还原反应以考察其多相催化性能。结果表明:优化条件下制备的Ni@Cage-C催化剂为碳笼包裹单质镍结构,其平均颗粒大小为550 nm;将Ni@Cage-C用于对硝基苯酚催化还原反应时,催化性能明显优于参照催化剂雷尼镍(Raney-Ni)。质量反应速率常数kM为6.11 mg^(-1)·min^(-1),催化效率达到98.87%,循环反应十圈后活性仍高于初始活性的85%。

Ni/活性炭催化剂上乙醇羰基化性能演变研究

活性炭负载的Ni基催化剂(Ni/AC)在乙醇多相羰基化反应中具有良好的活性,然而在反应过程中也存在着明显的失活,因此明确催化剂在反应过程中的失活机理和原因对于提高催化剂的稳定性至关重要.本文通过浸渍法制备了Ni/AC催化剂,并对不同反应时间的催化剂进行表征分析.研究结果表明,在助催化剂碘乙烷的作用下,反应初期Ni纳米颗粒再分散导致乙醇转化率升高,而随着反应进行,Ni物种出现聚集的现象,导致乙醇转化率明显降低.在乙醇羰基化反应过程中,催化剂中的积炭量不断增加,导致催化剂的比表面积和孔体积不断减小;结合相关表征发现积炭物种中存在产物丙酸、丙酸乙酯或含有丙酰基的中间体,且积炭对催化剂的CO吸附有抑制作用,从而使丙酸及丙酸乙酯的选择性降低.进一步研究表明,减少碘乙烷的比例会使催化剂的活性明显降低,但催化稳定性有所提高.

Nickel Sulfide/Graphene/Carbon Nanotube Composites as Electrode Material for the Supercapacitor Application in the Sea Flashing Signal System

This work presents NiS/graphene/carbon nanotube （NiS/GNS/CNT） composites as electrode material for the supercapacitor application in sea flashing signal systems. NiS nanosheets were closely anchored on the conductive GNS-CNT networks. As a result, the NiS/GNS/CNT electrode showed a high specific capacitance of 2 377 F.g^-1 at 2 mV.s^-1 and good cycling stability compared with the pure NiS （1 599F.g^-1）. The enhanced electrochemical performances are attributed to the synergetic effect between the conductive carbon and the pseudo-capacitive NiS. The high performance supercapacitor may provide application in the sea flashing signal system.

Syngas production by combined carbon dioxide reforming and partial oxidation of methane over Ni/α-Al_2O_3 catalysts

Ni/α-Al2O3 catalysts were found to be active in the temperature range 600 ～ 900℃ for both CO2 reforming and partial oxidation of methane.The effects of Ni loading,reaction temperature and feed gas ratio for the combination of CO2 reforming and partial oxidation of CH4 over Ni/α-Al2O3 were investigated.Catalysts of xwt%Ni/α-Al2O3（x=2.5,5,8 and 12） were prepared by wet impregnating the calcined support with a solution of nickel nitrate.XRD patterns and activity tests have verified that the 5wt%Ni/α-Al2O3 was the most active catalyst,as compared with the other prepared catalyst samples.An increase of the Ni loading to more than 5wt% led to a reduction in the Ni dispersion.In addition,by combining the endothermic carbon dioxide reforming reaction with the exothermic partial oxidation reaction,the loss of catalyst activity with time on stream was reduced with the amount of oxygen added to the feed.

A Novel Carbon Nanotube-Supported NiP Amorphous Alloy Catalyst and Its Hydrogenation Activity

A carbon nanotube-supported NiP amorphous catalyst （NiP/CNT） was prepared by induced reduction. Benzene hydrogenation was used as a probe reaction for the study of catalytic activity. The effects of the support on the activity and thermal stability of the supported catalyst were discussed based on various characterizations, including XRD, TEM, ICP, XPS, H2-TPD, and DTA. In comparison with the NiP amorphous alloy, the benzene conversion on NiP/CNT catalyst was lower, but the specific activity of NiP/CNT was higher, which is attributed to the dispersion produced by the support, an electron-donating effect, and the hydrogen-storage ability of CNT. The NiP/CNT thermal stability was improved because of the dispersion and electronic effects and the good heat-conduction ability of the CNT support.

单原子Ni、N共掺杂碳材料基催化剂电还原CO_(2)制CO研究进展

单原子Ni、N共掺杂碳材料基催化剂(Ni-N-C)电催化CO_(2)制CO,因其在较大的电流密度和较大的过电势下仍具有超高的CO选择性,引起了广泛关注。本文综述了Ni-N-C电催化CO_(2)制CO研究进展,包括氮掺杂碳材料基催化剂和Ni-N-C电催化CO_(2)制CO。总结了氮掺杂碳材料基催化剂中不同形态N的催化活性,目前为止,N在该类催化剂电化学还原CO_(2)中的确切作用没有达成共识。此外,还总结了Ni-N-C的催化性能、催化机理及催化性能改性方法,探讨了与Ni配位的N原子和缺陷位对催化活性的影响规律,分析了各类碳载体的优缺点。Ni-N-C电化学还原CO_(2)制CO研究已取得一定的进展,如电流密度可达工业级要求,但是其实现大规模工业化应用还需解决一些关键问题,如开发高活性和高稳定性Ni-N-C的定向制备技术;研发制备简易温和、成本低廉、具有抗腐蚀性、耐高温的先进碳载体材料。

Adsorption of Cu and Ni Ions from Aqueous Solutions by Commercial Activated Carbon and the Reutilization in Glass Coloration

Toxic Cu(Ⅱ) and Ni(Ⅱ) ions in aqueous solutions were adsorbed by microporous activated carbon(AC). The adsorption isotherm and kinetics correlation coefficients indicate that the adsorption of Cu(Ⅱ) and Ni(Ⅱ) ions on the AC fits the pseudo second-order rate model and Langmuir adsorption model. The used AC adsorbents containing the adsorbed Cu and Ni ions were used as colorant in glass preparation. The coloration effect of Cu ions was influenced by the carbon absorbent included in the glass batch due to the reduction phenomenon, while the coloration of Ni ions was not affected.

Modulating the CO methanation activity of Ni catalyst by nitrogen doped carbon

Nitrogen doping has been proved to be an effective way to modify the properties of graphene and other carbon materials. Herein, we explore a composite with nitrogen doped carbon overlayers wrapping Si C substrate as a support for Ni（Ni/CN-Si C） and evaluate its effects on the methanation activity. The results show that both the activity and stability of Ni are enhanced. Characterization with STEM, XRD, XPS, Raman and H2-TPR indicates that nitrogen doping generates more defects in the carbon overlayers, which benefit the dispersion of Ni. Furthermore, the reduction of Ni is facilitated.

Electrochemical performance of nickel hydroxide doped with multi-wall carbon nanotubes

Nickel hydroxide doped with multi-wall carbon nanotubes(MCNTs)was synthesized by chemical coprecipitation method. The MCNTs doped nickel hydroxide was used as the electrochemical active material in the positive electrodes of rechargeable alkaline batteries.The powder X-ray diffraction(XRD)analysis shows that the addition of MCNTs induces more structural defect within the crystal lattice of the nickel hydroxide.The cyclic voltammetry(CV)and electrochemical impedance spectroscopy(EIS) tests demonstrate the better reaction reversibility and lower electrochemical impedance of MCNTs doped nickel hydroxide as compared with the pure nickel hydroxide.The charge/discharge tests show that MCNTs addition can improve the specific discharge capacity and increase the discharge voltage of the nickel hydroxide electrode.

Effect of MgO promoter on Ni-based SBA-15 catalysts for combined steam and carbon dioxide reforming of methane

A series of Ni/SBA-15 catalysts with Ni contents ranging from 5 wt% to 15 wt%, as well as another series of 10%Ni/MgO/SBA-15 catalysts, in which the range of the MgO content was from 1 wt% to 7 wt%, were prepared, and their catalytic performances for the reaction of combined steam and carbon dioxide reforming of methane were investigated in a continuous flow microreactor. The structures of the catalysts were characterized using the XRD, H2-TPR and CO2-TPD techniques. The results indicated that the CO selectivity for this reaction was very close to 100%, and the H2/CO ratio of the product gas could be controlled by changing the H2O/CO2 molar ratio of the feed gas. The simultaneous and plentiful existing of steam and CO2 had a significant influence on the catalytic performance of the 10%Ni/SBA-15 catalyst without modification. After reacting at 850 °C for 120 h over this catalyst, the CH4 conversion dropped from 98% to 85%, and the CO2 conversion decreased from 86% to 53%. However, the 10%Ni/3%MgO/SBA-15 catalyst exhibited a much better catalytic performance, and after reacting for 620 h, the CO2 conversion over this catalyst dropped from 92% to around 77%, while the CH4 conversion was not decreased. Oxidation of the Ni0 species as well as carbon deposition during the reaction were the main reasons for the deactivation of the catalyst without modification. On the other hand, modification by the MgO promoter improved the dispersion of the Ni0 species, and enhanced the CO2 adsorption affinity which in turn depressed the occurring of carbon deposition, and thus retarded the deactivation process.

Production of Carbon Nanotubes and Hydrogen Catalyzed with Ni/MCM-41 Catalysts

Methane catalytic decomposition (MCD) over Ni/MCM-41 catalysts was tested in a microreactor to simultaneously produce hydrogen and carbon nanotubes (CNTs). The methane conversion reached 30% to 47% at a moderate temperature range from 400°C to 600°C and the catalytic activity of the catalysts remains stable during 500 min steam on time. CNTs were chiefly formed through tip-growth mode, due to the weak interaction between the metallic Ni and the support. Most of the Ni particles are located on the tip of the produced CNTs, which avoids rapid deactivation of the catalyst resulted from carbon encapsulation. Large Ni particles usually lead to the formation of CNTs with big diameter. During the reaction, the shape of Ni particles changed from pseudo-sphere to diamond-like. All the CNTs consist of multiple layer walls and are curved in certain degree.

Nanoscale Ni-B amorphous alloy catalyst supported on carbon nanotubes

Heat treatment of carbon nanotubes(CNTs) was carried out under ammonia atmosphere and then CNTs were modified by Triton x-100(CNTs-T). Ni-B amorphous alloy catalysts supported on CNTs and CNTs-T were prepared by impregnation-chemical reduction method. The catalysts were characterized by TEM,ICP,XRD,BET and CO chemisorption,and studied in the acetylene selective hydrogenation. The results show that homogeneous Ni-B amorphous particles with mean size about 10 nm are successfully prepared on CNTs-T. Compared with Ni-B/CNTs,nickel loading of Ni-B/CNTs-T is increased by about 14.6%. Furthermore,the activity and selectivity of Ni-B/CNTs-T are much higher than those of Ni-B/CNTs in the acetylene selective hydrogenation under comparative condition.

用于尿素氧化的介孔Ni-NiO@NC电极构造

电催化尿素氧化反应(UOR)可作为直接尿素燃料电池(DUFC)的阳极反应。采用水热联合热解的方法,在介孔含氮碳基体(NC)上构建了锚定Ni和NiO晶体异质结的UOR电催化剂。在1.67 V时,优化工艺合成的Ni-NiO@NC-500复合材料的碱性介质UOR阳极峰值电流密度为237 mA/cm2,在10 mA/cm2的UOR的电势为1.38 V(vs RHE)。12 h的CA循环电流密度>80%。Ni-NiO@NC-500良好的电催化活性关键在于Ni和NiO之间形成了异质结,界面处存在协同作用,Ni/NiO异质结不仅提供了更多的UOR活性位点,而且有利于尿素吸附和气体产物解吸。此外,N掺杂调节了复合材料的电子密度,加快了UOR过程中的电子传递,其介孔结构有利于电解质的渗透和电子转移,其NC提高了催化剂的稳定性。Ni-NiO@NC-500材料将有望成为一种高效、低成本的UOR电催化剂。

Carbon dioxide reforming of methane on monolithic Ni/Al_2O_3-based catalysts

Nickel-alumina catalysts supported on cordierite monoliths of honeycomb structure surpass essentially the conventional granulated ones with respect to the output in carbon dioxide reforming of methane. Adjusting the surface acid-base properties of catalysts by introduction of alkali metal （Na, K） oxides inhibits the carbonization and as a result, improves the operational stability of these catalysts. An effect of promotion of nickel-alumina based composite doped by lanthanum oxide is found. This effect, caused by an additional route for the CO2 activation on Ni-La2O3/Al2O3/cordierite catalyst, is displayed in increase of methane conversion under conditions of an oxidant excess.

Improving the field-emission properties of carbon nanotubes by magnetically controlled nickel-electroplating treatment

A novel magnetically controlled Ni-plating method has been developed to improve the field-emission properties of carbon nanotubes （CNTs）. The effect of the magnetic field and Ni-electroplating on CNT field-emission properties was investigated, and the results are demonstrated using scanning electron microscopy, J-E and the duration test. After treatment, the turn-on electric field declines from 1.55 to 0.91 V/μm at an emission current density of 100μA/cm2, and the emission current density increases from 0.011 to 0.34 mA/cm2 at an electric field of 1.0 V/μm. Both the brightness and uniformity of the CNT emission performance are improved after treatment.

载体形貌调控Ni基催化剂甲烷干重整反应性能的研究

甲烷干重整(DRM)反应对于温室气体CO_(2)和CH_(4)的共转化利用具有重要的研究意义。然而,该反应在实际应用中面临着催化剂容易积碳而失活的问题。通过制备花状、颗粒状以及片状MgO负载的Ni基催化剂,考察了载体形貌对催化剂DRM反应性能的影响,并结合XRD、SEM、H_(2)-TPR、CO_(2)-TPD和TG等表征手段对其影响机制进行了阐述。结果表明,在温度为800℃、空速为54000 mL/(g·h)下,经过50 h反应后,花状MgO负载的Ni基催化剂的CO_(2)和CH_(4)的平均转化率分别达到了90.2%和82.3%,n(H_(2))/n(CO)的平均值为0.93,与颗粒状和片状MgO负载的催化剂相比,具有较高的活性、稳定性和抗积碳性能。这是由于花状MgO负载的Ni基催化剂具有较高的比表面积,有利于活性金属的分散。同时,花状MgO表面存在更多的碱性位点,有利于CO_(2)的吸附活化,增强催化剂抗积碳性能,提高DRM反应活性与稳定性。

Carbon Nanotubes Supported Pt-Ru-Ni as Methanol Electro-Oxidation Catalyst for Direct Methanol Fuel Cells

Carbon nanotubes （CNTs） supported Pt-Ru and Pt-Ru-Ni catalysts were prepared by chemical reduction of metal precursors with sodium borohydride at room temperature. The crystallographic properties and composition of the catalysts were characterized by X-ray diffraction （XRD） and energy dispersive X-ray （EDX） analysis, and the catalytic activity and stability for methanol electro-oxidation were measured by electrochemical impedance spectroscopy （EIS）, linear sweep voltammetries （LSV）, and chronoamperometry （CA）. The results show that the catalysts exhibit face-centered cubic （fcc） structure. The particle size of Pt-Ru-Ni/CNTs catalyst is about 4.8 nm. The catalytic activity and stability of the Pt-Ru-Ni/CNTs catalyst are higher than those of Pt-Ru/CNTs catalyst.

Ore Genesis of the Kalatongke Cu-Ni Sulfide Deposits, Western China: Constraints from Volatile Chemical and Carbon Isotopic Compositions

The Kalatongke Cu-Ni sulfide deposits located in the East Junggar terrane, northern Xinjiang, western China are the largest magmatic sulfide deposits in the Central Asian Orogenic Belt （CAOB）. The chemical and carbon isotopic compositions of the volatiles trapped in olivine, pyroxene and sulfide mineral separates were analyzed by vacuum stepwise-heating mass spectrometry. The results show that the released volatiles are concentrated at three temperature intervals of 200-400°C, 400-900°C and 900-1200°C. The released volatiles from silicate mineral separates at 400-900°C and 900-1200°C have similar chemical and carbon isotopic compositions, which are mainly composed of H2O （av. ~92 mol%） with minor H2, CO2, H2S and SO2, and they are likely associated with the ore-forming magmatic volatiles. Light δ13CCO2 values （from -20.86‰ to -12.85‰） of pyroxene indicate crustal contamination occurred prior to or synchronous with pyroxene crystallization of mantlederived ore-forming magma. The elevated contents of H2 and H2O in the olivine and pyroxene suggest a deep mantle-originated ore-forming volatile mixed with aqueous volatiles from recycled subducted slab. High contents of CO2 in the ore-forming magma volatiles led to an increase in oxygen fugacity, and thereby reduced the solubility of sulfur in the magma, then triggered sulfur saturation followed by sulfide melt segregation; CO2 contents correlated with Cu contents in the whole rocks suggest that a supercritical state of CO2 in the ore-forming magma system under high temperature and pressure conditions might play a key role in the assemblage of huge Cu and Ni elements. The volatiles released from constituent minerals of intrusion 1# have more CO2 and SO2 oxidized gases, higher CO2/CH4 and SO2/H2S ratios and lighter δ13CCO2 than those of intrusions 2# and 3#. This combination suggests that the higher oxidation state of the volatiles in intrusion 1# than intrusions 2# and 3#, which could be one of key ore-forming factors for large amounts of ores and high contents of Cu and Ni in intrusion 1#. The volatiles released at 200-400°C are dominated by H2O with minor CO2, N2＋CO and SO2, with δ13CCO2 values （-25.66‰ to -22.98‰） within the crustal ranges, and are considered to be related to secondary tectonic-hydrothermal activities.