Hydrogen production via steam reforming of bio-oil model compounds over supported nickel catalysts

The steam reforming of four bio-oil model compounds（acetic acid,ethanol,acetone and phenol） was investigated over Ni-based catalysts supported on Al2O3 modified by Mg,Ce or Co in this paper.The activation process can improve the catalytic activity with the change of high-valence Ni（Ni2O3,NiO） to low-valence Ni（Ni,NiO）.Among these catalysts after activation,the Ce-Ni/Co catalyst showed the best catalytic activity for the steam reforming of all the four model compounds.After long-term experiment at 700°C and the S/C ratio of 9,the Ce-Ni/Co catalyst still maintained excellent stability for the steam reforming of the simulated bio-oil（mixed by the four compounds with the equal masses）.With CaO calcinated from calcium acetate as CO2 sorbent,the catalytic steam reforming experiment combined with continuous in situ CO2 adsorption was performed.With the comparison of the case without the adding of CO2 sorbent,the hydrogen concentration was dramatically improved from 74.8% to 92.3%,with the CO2 concentration obviously decreased from 19.90% to 1.88%.

Catalytic Transformation of Oxygenated Organic Compounds into Pure Hydrogen

The continual growth in transportation fuels and more strict environmental legislations have led to immense interest in developing green biomass energy. In this work, a proposed catalytic transformation of oxygenated organic compounds （related to bio-oil） into pure hydrogen was desighed, involving the catalytic reforming of oxygenated organic compounds to hydrogen- rich mixture gas followed by the conversion of CO to CO2 via the water gas reaction and the removal of CO2. The optimization of the different reforming catalyst, the reaction conditions as well as various sources of oxygenated organic compounds were investigated in detail. The production of pure hydrogen, with the H2 content up to 99.96% and the conversion of 97.1%, was achieved by the integrated catalytic transformation. The reaction pathways were addressed based on the investigation of decomposition, catalytic reforming, and the water gas reaction.

Inhibiting effect of tungstic compounds on glucose hydrogenation over Ru/C catalyst

The effect of acid component including various conventional acids and tungstic compounds on glucose hydrogenation over a series of binary catalyst system containing Ru/C catalyst was investigated. The results showed that HC1, H2SO4, H3BO3, H3PO4, and HNO3 had negligible effect, while all the tungstic compounds imposed inhibiting effects on the hydrogenation of glucose over Ru/C catalyst, and the suppressing effect followed the order of H2WO4〉HPW〉WO3〉AMT〉HSiW. This order is the same as the order of ethylene glycol （EG） yields in the one-pot conversion of glucose to EG, suggesting the important role of competition between glucose hydrogenation and retro-aldol condensation in controlling the selectivity of EG.

SURFACE REACTION，HYDROGEN DIFFUSIVITY AND ENVIRONMENTAL EMBRITTLEMENT OF INTERMETALLIC COMPOUNDS Ni_3Al AND Fe_3Al

The effect of boron doping on the sensitivity to environmental embrittlement of Ni3Al-based alloys was investigated in this paper. The results show that the ductilizing effect of boron in Ni3Al is partly to suppress moisture-induced hydrogen embrittlement.The mechanism of this suppressing effect of boron relates to its severely decreasing the hydrogen diffusivity by boron segregated at the grain boundaries. The surface reaction of Fe3Al with water vapor and oxygen was experimentally confirmed by AES and XPS analysis. The kinetics of these reactions can be used to explain the different ductility behavior of aluminides in various environments.

Distribution and Form of Iron and Calcium Compounds Before and After Residue Hydrogenation Under Different Space Velocities

The distribution and form of iron and calcium compounds were studied using hydrogenation feedstock and hydrogenation products with different space velocities as the research object.The content of metallic elements,such as calcium and iron in hydrogenation feedstock,and extract samples were determined via flame atomic absorption spectrometry.The water-soluble iron and calcium species in oil samples were determined by an IC2010 high-throughput ion chromatograph.Nearly 60%-80%of the iron or calcium compounds were mainly concentrated in resins and asphaltenes.Iron and calcium compounds mainly exist in the form of oil-soluble metal species in hydrogenation feedstock and hydrogenation products.Under certain conditions of reaction temperature,pressure,and volume ratio of hydrogen to oil,when the reaction space velocity was 0.6 h^(−1),about 30%of the iron or calcium compounds were converted from oil-soluble to water-soluble species after hydrogenation.When the reaction space velocity was decreased from 1.70 to 0.60 h^(−1),the proportion of iron compounds converted from oil-soluble to water-soluble increased from 8.4%to 28%.Moreover,the proportion of calcium compounds converted from oil-soluble to water-soluble increased from 10%to 37%.This denotes that with decreasing reaction space velocity,the ratio of oil-soluble to water-soluble species increases.Water-soluble iron and calcium compounds are present in the form of inorganic salts,such as chlorate and sulfate.This study helps in understanding the removal mechanism of iron and calcium compounds and optimizing the operating conditions of residue hydrogenation.

High-capacity Hydrogen Storage on Novel Sandwich-like Binuclear Compounds: N_4-M_2-N_4 (M = Sc and Ti)

With respect to the first principle calculations, we predicted that two pairs of transition metals （e.g., Sc2 and Ti2） can be interbedded between two tetranitrogen rings to form two sandwich-like binuclear complexes respectively （e.g. N4Sc2N4 and NaTi2N4）. These two complexes can adsorb up to eight and ten hydrogen molecules, corresponding to a gravimetric storage capacity of 7.7 and 9.9 wt%, respectively. These sandwich-type complexes proposed in this work are favorable for reversible adsorption and desorption of hydrogen at ambient conditions. The results are helpful for the development of a new class of high-capacity hydrogen-storage media.

Review on Metal-Acid Tandem Catalysis for Hydrogenative Rearrangement of Furfurals to C_(5) Cyclic Compounds

Hydrogenative rearrangement of biomas s-derived furfurals(furfural and 5-hydroxymethyl furfural) to C_(5) cyclic compounds(such as cyclopentanones and cyclopentanols) offers an expedient reaction route for acquiring O-containing value-added chemicals thereby replacing the traditional petroleum-based approaches.The scope for developing efficient bifunctional catalysts and establishing mild reaction conditions for upgrading furfurals to cyclic compounds has stimulated immense deliberation in recent years.Extensive efforts have been made toward developing catalysts for multiple tandem conversions,including those with various metals and supports.In this scientific review,we aim to summarize the research progress on the synergistic effect of the metal-acid sites,including simple metal-supported acidic supports,adjacent metal acid sites-supported catalysts,and in situ H_(2)-modified bifunctional catalysts.Distinctively,the catalytic performance,catalytic mechanism,and future challenges for the hydrogenative rearrangement are elaborated in detail.The methods highlighted in this review promote the development of C_(5) cyclic compound synthesis and provide insights to regulate bifunctional catalysis for other applications.

1-烃基异喹啉Reissert Compounds的合成及其氢化研究

1-苄基异喹啉Reissert compound经Raney Ni(w-2)催化氢化,分离得到二个未见报道的氢化产物,经化学和波谱分析推定其结构为:1-亚氨基-1-苄基-2-苯甲酰基-1,2-二氢异喹啉(4)和3-苯基-10b-苄基-1,10b-二氢咪唑骈[5,1-a]异喹啉(5)。据此提出了一条1-苄基异喹啉Reissert compound高压催化氢化的途径,并对异喹啉Reissert compound高压催化氢化反应中酰基转位进行了讨论。试图以环已基溴作为烷化剂,在氢化钠条件下,与异喹啉Reissert compound作用来制备1-环已基异喹啉Reissert compound,结果只得到了1-氰基异喹啉,产率达75％,为制备1-氰基异喹啉提供了一个新方法。

Hydrogen storage properties of Zr_(1-x)Ti_xCo intermetallic compound

The intermetallic compound Zr1-xTixCo was prepared and its suitability for hydrogen storage was investigated. The alloys obtained by magnetic levitation melting with the composition of Zr1-xTixCo (x=0, 0.1, 0.2 and 0.3, at.%) show single cubic phase by X-ray diffraction. A single sloping plateau was observed on each isothermal, and pressure-composition-temperature (PCT) measurement results show that the equilibrium hydrogen desorption pressure of Zr1-xTixCo alloy increases with increasing Ti content. The desorption temperatures for supplying 100 kPa hydrogen are about 665, 642, 621 and 614 K for ZrCo, Zr0.9Ti0.1Co, Zr0.8Ti0.2Co and Zr0.7Ti0.3Co alloy, respectively. Repeated hydrogen absorption and desorption cycles do not generate separated ZrCo, TiCo and ZrH2 phases, indicating that alloys have good thermal and hydrogen stabilization.

Selective hydrogenation of acetylene on SiO_2-supported Ni-Ga alloy and intermetallic compound

Ni/Si O_2 and bimetallic Ni_xGa/SiO_2 catalysts with different Ni/Ga atomic ratios(x = 10～2) were investigated for the selective hydrogenation of acetylene.It was found that Ni_xGa/SiO_2 showed higher selectivity to ethylene than Ni/Si O_2.This is attributed to the formation Ni-Ga alloy and Ni3 Ga intermetallic compound(IMC) where there was a charge transfer from Ga to Ni,which is favorable for reducing the adsorption strength and amount of ethylene on Ni atoms.As a result,the over-hydrogenation,the C–C bond hydrogenolysis and the polymerization were suppressed,and subsequently the selectivity to ethylene was enhanced.With the decrease of Ni/Ga atomic ratio,the activity and stability of the Ni_xGa/SiO_2 catalysts increased first and then decreased,while the ethylene selectivity tended to increase.Ni_5 Ga/SiO_2 exhibited the best performance.Under the conditions of 180 °C,0.1 MPa,and a reactant(1.0 vol% acetylene,5.0 vol% H_2 and 94 vol% N_2) with the space velocity of 36,000 m L h^(-1) g^(-1),the acetylene conversion maintained at 100% on Ni_5 Ga/SiO_2 during 120 h time on stream and the selectivity to ethylene was 75%～81%after reaction for 68 h.It was also found that the formation of Ni-Ga alloy and Ni_3 Ga IMC suppressed the incorporation of carbon to form NiCx,subsequently enhancing the catalyst stability.Additionally,with increasing the Ga content,the catalyst acid amount and strength tended to increase,which promoted the polymerization and carbon deposition and so the catalyst deactivation.

Synthesis of Intermetallic Compounds by Using Lithium Hudride

Intermetallic compounds of AB 5 type are promising materials for M-H batteries. In this report we present the results about the influence of quality of intermetallic compounds prepared by a new method of synthesis on their electrochemical properties. The well-known intermetallic Ln 1-xM xNi 5-yMe y (Ln=La, Mm; M=Zr; Me=Mn, Ge, Sn, Al, Co+Sn, Co+Ge) compounds were synthesized by using mixtures of oxides, chlorides and carbonates of metals by interaction with lithium hydride at 700～1000 ℃. Prepared samples have the uniform microstructure with average dimension of particles about 20～30 μm. Electrochemical tests show that kinetic behaviour of compositions are satisfactory under current up to 200 mA·g -1. These compositions require practically no activation and limiting values of the discharge capacity were reached at 2～3 cycle up to 300 mAh·g -1, which can be considered as most promising for practice.

Synthesis and Structure of a Hydrogen-bonding Assembled Three-dimensional Supramolecular Indium(III) Compound Involving One-dimensional Helices

The title compound [In（H2ip）（pdc）（H2O）] （H3ip = 5-hydroxyisophthalic acid, H2Pdc = pyridine-2,6-dicarboxylic acid） has been synthesized and characterized by single-crystal X-ray diffraction analysis. It crystallizes in monoclinic, space group P21/c with a = 13.830（8）, b = 6.488（4）, c = 17.632（10）A^°, β = 92.510（10）°, C15H10InNO10, Mr= 479.06, V = 1580.6（15）A^°3, Z = 4, De= 2.013 g/cm^3, F（000） = 944,μ = 1.557 mm^-1, the final R = 0.0413 and wR = 0.0793 for 2950 observed reflections with I 〉 2σ（I）. The In（Ⅲ） ion is seven-coordinated in a slightly distorted penta-bipyramidal geometry. The mixed ligands connect the In（Ⅲ） ions into 21 helical chains along the [010] direction, and the hydrogen bonds assemble the chains into a three-dimensional supramolecular network.

A MATHEMATICAL MODEL FOR THE STABILITY OF THEHYDRIDES OF Ca CONTAINING RNi_5 COMPOUNDS

In this paper, a mathematical model for the stability of hydrides of Ca containing compounds was proposed on the basis of introducing the geometrical and electric factors. The data on (R, Ca)Ni5 compounds are in good agreement with the theoretical curve obtained from the model. For Ml1-x CaxNi5 compounds, the variation of dissociation pressure with cell volume is the joint effects of geometrical and electric factors, and the controlling factor changes gradually from geometrical factor to electric factor with increasing x.

Surface Properties of Cu Doped La-Ni Intermetallic Compounds

A series of Cu-doped La-Ni intermetallic compounds(LaN5-xCux, x = 0-4) was studied. The bulk structure and surface composition of the samples were detected before and after they were used as catalyst for nitrobenzene hydrogennation. The catalytic properties of the intermetallic compounds depend on the surface region composition, especially on the valence of the metal ions.

Thermal Behavior,Sensitivity,Detonation Velocity and Pressure of a Nitrogen-Rich Compound

The nitrogen content of tetrazolo triazines is 68.9%.In this paper,tetrazolotriazines was synthetized.The TG-DSC test indicated its decomposition process in detail.The non-isothermal kinetic parameters were speculated by Kissinger and Ozawa methods.It revealed the mechanism function of thermal decomposition.The impact and friction sensitivity were tested.The detonation pressure and velocity were calculated.It has a wide range of potential applications as a kind of energetic material.

Auto-thermal reforming of acetic acid for hydrogen production by Zn_(x)Ni_(y)CrO_(m±δ) catalysts:Effect of Cr promoted Ni-Zn intermetallic compound

A series of Zn_(x)Ni_(y)CrO_(m±δ)catalysts were synthesized via a typical co-precipitation method,in which Zn-Cr layered double hydroxides(LDHs)were found and Ni-Zn intermetallic compound(IMC)was formed after reduction in hydrogen.During auto-thermal reforming(ATR)of acetic acid(HAc),the Ni-Zn IMC was transformed into Ni/(amorphous-ZnO)-ZnCr_(2)O_(4) species with uniformed distribution and appropriate interaction within these Ni-Zn-Cr-O species;besides,the adsorbed oxygen promoted the activation and transfer of oxygen species;therefore,deactivation by oxidation,sintering and coking was inhibited.And the optimized Zn_(2.37)Ni_(0.63)CrO_(4.5±δ)catalyst presented high activity and stability in a 45-h ATR test with HAc conversion near 100%and hydrogen yield at 2.7 mol-H_(2)/mol-HAc,showing potential for hydrogen production via ATR of HAc.

Porous TiFe_(2) intermetallic compound fabricated via elemental powder reactive synthesis

Porous intermetallics show potential in the field of filtration and separation as well as in the field of catalysis.Herein,porous Ti Fe2intermetallics were fabricated by the reactive synthesis of elemental powders.The phase transformation and pore formation of porous TiFe2intermetallics were investigated,and its corrosion behavior and hydrogen evolution reaction(HER)performance in alkali solution were studied.Porous TiFe2intermetallics with porosity in the range of 34.4%-56.4%were synthesized by the diffusion reaction of Ti and Fe elements,and the pore formation of porous TiFe2intermetallic compound is the result of a combination of the bridging effect and the Kirkendall effect.The porous TiFe2samples exhibit better corrosion resistance compared with porous 316L stainless steel,which is related to the formation of uniform nanosheets on the surface that hinder further corrosion,and porous TiFe2electrode shows the overpotential of 220.6 and 295.6 mV at 10 and 100 mA·cm-2,suggesting a good catalytic performance.The synthesized porous Fe-based intermetallic has a controllable pore structure as well as excellent corrosion resistance,showing its potential in the field of filtration and separation.

Decomposition of a β-O-4 lignin model compound over solid Cs-substituted polyoxometalates in anhydrous ethanol: acidity or redox property dependence?

Production o f aromatics from lignin has attracted much attention. Because of the coexistence of C-O and C-C bonds and their complex combinations in the lignin macromolecular network, a plausible roadmap for developing a lignin catalytic decomposition process could be developed by exploring the transformation mechanisms of various model compounds. Herein, decomposition of a lignin model compound, 2-phenoxyacetophenone （2-PAP）, was investigated over several ce-sium-exchanged polyoxometalate （Cs-POM） catalysts. Decomposition of 2-PAP can follow two dif-ferent mechanisms： an active hydrogen transfer mechanism or an oxonium cation mechanism. The mechanism for most reactions depends on the competition between the acidity and redox proper-ties of the catalysts. The catalysts of POMs perform the following functions： promoting active hy-drogen liberated from ethanol and causing formation of and then temporarily stabilizing oxonium cations from 2-PAP. The use of Cs-PMo, which with strong redox ability, enhances hydrogen libera-tion and promotes liberated hydrogen transfer to the reaction intermediates. As a consequence, complete conversion of 2-PAP （〉99%） with excellent selectivities to the desired products （98.6% for phenol and 91.1% for acetophenone） can be achieved.

Environmental Embrittlement of Fe-based, Co-based, Ni-based and Ti-based Intermetallics in Gaseous Hydrogen

The environmental embrittlement of intermetallics Co3Ti, Ni3Al, Fe3Al and TiAl has been investigated by measuring the tensile properties in oxygen and hydrogen at 2×l0-4/s strain rate. The results show that the hydrogen embrittlement factor in gaseous hydrogen (IH2 ) defined as[(δO2 -δH2 ) / δH2, ] ×l00% of above mentioned four intermetallics is decreased in the sequence of Co3Ti> Ni3Al> Fe3Al> TiAl. This phenomena can be explained by the different catalytic reaction on the surface of matrix metals (such as Ni, Co, Fe, Ti) with decomposition of H2 into atommic hydrogen, leading to hydrogen embrittlement.

AB_(2)-type rare earth-based compounds with C-15 structure:Looking for reversible hydrogen storage materials

AB_(2)-type(A=rare earth,B=transition metal)intermetallic compounds with C15 structure can easily absorb large amount of hydrogen,showing their potential use as hydrogen storage materials.The crucial problem hindering their application is hydrogen induced amorphization(HIA),which leads to the irreversible hydrogen sorption process.The stability of the AB_2 Laves phase compounds,the structural properties,the hydrogenation properties and the controlling factors of HIA are discussed in this review.Comparing with other factors,the atomic radii ratio r_A/r_B is the most important one influencing the HIA.Multi-element substitution is an efficient way to suppress or limit HIA and may enable AB_2 compounds to be suitable for hydrogen storage.