Exciting lattice oxygen of nickel–iron bi-metal alkoxide for efficient electrochemical oxygen evolution reaction

High efficiency,cost-effective and durable electrocatalysts are of pivotal importance in energy conversion and storage systems.The electro-oxidation of water to oxygen plays a crucial role in such energy conversion technologies.Herein,we report a robust method for the synthesis of a bimetallic alkoxide for efficient oxygen evolution reaction(OER)for alkaline electrolysis,which yields current density of 10 mA cm^(-2)at an overpotential of 215 mV in 0.1 M KOH electrolyte.The catalyst demonstrates an excellent durability for more than 540 h operation with negligible degradation in activity.Raman spectra revealed that the catalyst underwent structure reconstruction during OER,evolving into oxyhydroxide,which was the active site proceeding OER in alkaline electrolyte.In-situ synchrotron X-ray absorption experiment combined with density functional theory calculation suggests a lattice oxygen involved electrocatalytic reaction mechanism for the in-situ generated nickel–iron bimetal-oxyhydroxide catalyst.This mechanism together with the synergy between nickel and iron are responsible for the enhanced catalytic activity and durability.These findings provide promising strategies for the rational design of nonnoble metal OER catalysts.

STUDIES ON THE SYNTHESIS AND REACTIONWITH ALKOXIDES OF 3－OXO－1，2－BENZOISOTHIAZOLINE－2－ACETAMIDE1，1－DIOXIDES

New 3 -oxo-benzoisothiazoline-2-acetamide 1, 1-dioxides (IIa-b) ware synthesizedand whose reaction with alkoxides was studied. The reaction results indicated that differentproducts were obtained owing to the different time of reaction with alkoxides

Synthesis and Crystal Structure of Novel Mixed-metal Alkoxide Clusters of Ytterbium and Sodium: Yb_4O_4(O^iPr)_(16)Na_(12)

The mixed-metal cluster Yb4O4（OiPr）16Na12 has been synthesized and structurally determined by IR, elemental analysis, and single-crystal X-ray diffraction. The crystal belongs to the cubic system, space group P23 with a = b = c = 13.9788（3）A, V = 2731.55（10）A3, Z = 1, Dc = 1.202 g/cm3, Mr = 1977.42,/J = 3.480 mm-1, F（000） = 972, the final R = 0.0288 and wR = 0.1511 for 1677 observed reflections with I 〉 2σ（I）. X-ray analysis reveals that Yb4O4（Oipr）16Na12 is centrosym- metric and the structure contains four ytterbium metals and twelve sodium metals, and each ytterbium atom is coordinated by six oxygen atoms. In addition, an ancillary computational analysis of the optimized molecular unit was provided. The large energy gap （3,31 eV） between HOMO and LUMO indicates that the structure framework is particularly stable.

Synthesis and Characterization of Chiral Binuclear Organolanthanide and Yttrium Alkoxides Containing Cyclopentudienyl Ligand

Three new chiral binuclear organolanthanide alkoxides containing cyclopentadienyl ligand have been synthesised by the reaction of Cp3Ln (Cp=C5H5; Ln=Yb, Y, Dy ) with 0.5equimolar chiral diol in THF (tetrahydrofuran) at -78℃ at room temperature. All the complexes were characterized by elemental analysis, IR and MS spectra.

Quantum Chemical Calculation on Preparation of YBa＿2Cu＿3O＿（7－δ） Powders by Hydrolysis of Metal Alkoxides

The structural characteristics of different alkoxides of Y. Ba and Cu are studied with quantum chemi-cal CNDO /2 calculations. The relative hydrolysis rate coefficients k_M of them are obtained according tothe relationship between frontier orbitals and organic chemical reactions. Based on the above results. properexperimental conditions for the preparation of homogeneous ultra-purity. submicro high-T_cYBa_2Cu_3O_(7-δ) superconducting powders are proposed.

Anionic Copolymerization of Carbonyl Sulfide with Epoxides via Alkali Metal Alkoxides

Carbonyl sulfide （COS）, an analogue of carbon dioxide （CO2）, can be converted to CO2 via the carbonic anhydride enzymes widely existing in nature. COS is an ideal monomer for making poly（monothiocarbonate）s, which are difficult to synthesize by traditional methods. Herein, for the first time, we describe an anionic copolymerization of COS with epoxides using alkali metal alkoxides as the catalysts （initiators）, affording poly（monothiocarbonate）s with 100% alternating degree, 〉99% tail-to-head （T-H） content, high number-average molecular weights （Mns, up to 90.3 kg/mol） with narrow molecular weight distributions （D=Mw/Mn, 1.05-1.31 for COS/propylene oxide copolymers） under solvent-free and mild conditions. Oxygen-sulfur exchange reaction （O/S ER）, which can result in the production of contaminated dithiocarbonate and carbonate units in the main chain, was nearly completely depressed at 0 ℃. In addition, in contrast to previously reported salen chromium （iron） complexes that required multiple synthetic steps, this work provides simple, low-cost, and effective catalysts for making colorless sulfur-containing polymers.

Bimetallic amine-bridged bis(phenolate) lanthanide aryloxides and alkoxides: synthesis, characterization, and application in the ring-opening polymerization of rac-lactide and rac-β-butyrolactone

A series of neutral bimetallic lanthanide aryloxides p-C6H4[OLnL(THF)n]2 [Ln = Y(1), Yb(2), Sm(3)(n = 1) and La(4)(n = 2), L = Me2NCH2CH2N{CH2-(2-O–C6H2–tBu2-3,5)}2] and alkoxides p-C6H4CH2[OLnL(THF)]2 [Ln = Y(5), Yb(6)] supported by an amine-bridged bis(phenolate) ligand have been synthesized through one-pot reactions of Ln(C5H5)3(THF), LH2 with p-benzenediol and 1,4-benzenedimethanol, respectively. All complexes have been fully characterized by elemental analyses, single-crystal X-ray diffraction analysis, and IR and multi-nuclear NMR spectroscopy(in the cases of 1, 4 and 5). Study of their catalytic behavior revealed that, in general, all complexes are efficient initiators for the polymerization of rac-lactide(LA) and rac-β-butyrolactone(BBL), except for 3 and 4 in the case of BBL. The influence imposed by lanthanides of different ionic radii and initiating groups of different structures on the activity, controllability, and stereoselectivity of polymerization were systematically studied and compared. Highly heterotactic PLA(Pr up to 0.99) and syndiotactic PHB(Pr ≈ 0.81) with high molecular weight and narrow polydispersity formed and were automatically capped with hydroxyl functionality at both ends.

LOW-TEMPERATURE SYNTHESIS AND STUDY OF LUMINOPHOR Al_2O_3-SiO_2:Eu^(3+), Bi^(3+) USING METAL ALKOXIDE

Ⅰ. INTRODUCTION A kind of chemical wet process developed at the beginning of the seventies is the sol-gel method. Because of its lower synthesis temperature in inorganic materials, it is also called lowtemperature synthesis method. The sol-gel method has many obvious advantages compared with the high-temperature solid state reaction. On the one hand, the lower

Ring-opening Polymerization of Lactones With Rare Earth Compound as Catalyst—— Polymerization of ε-caprolactone by Rare Earth Alkoxides

Recently, much attention has been paid to poly (ε-caprolactone) (PCL) since it is biodegradable with the release of nontoxic byproduct in vivo and miscible with a variety of polymers. Therefore it has already been used as materials of sustaining drug release, dental prostheses, as well as a new raw material of polyurethanes and long life plasticizer of poly(vinyl chloride).

Synthesis and Characterization of Fluoro- and Chloro-bimetallic Alkoxides as Precursors for Luminescent Metal Oxide Materials via Sol-Gel Technique

Heterobimetallic alkoxides are broadly recognized as versatile precursors for luminescence materials, and efforts are being made to develop novel routes by applying the concept of geometrical molecular design, for their synthesis and to design a single source precursor suited to photoluminescent materials. Novel and new series of bimetallic alkoxides has been prepared by metathesis route. They exhibit a lower sensitivity towards hydrolysis and so they are easier to handle as compared to other alkoxides. All the compounds were characterized by elemental analysis, FT-IR and multinuclear NMR spectroscopies. FT-IR revealed that the molecular structure of these metal alkoxides was retained to a large extent in 4 ： 1 halogenated alcohol-benzene solution. The heteronuclear NMR spectroscopy provided useful information about chemical shifts for better understanding the likely structure based on interactions with their coordinate metals. The mass spectra show similar types of fragmentation pattern. SEM-EDS analyses showed consistency with the formulation. XRD patterns show an enhanced homogeneity at high temperature. TGA measurements show that thermal decomposition occured in steps that depended entirely on the chemical compositions and the synthesis routes. SEM observation reveals that the morphology and particle size strongly depend on synthesis routes for their precursors.

Structural comparison to the molybdenumsite of nitrogenase Synthesis and crystal structure of binuclear oxomolybdenum(V)complex with both omercaptophenolate and alkoxide ligands

Complex(n-Bu_4N)[Mo_2O_2(OMe)(mp)_3][1,mp=(o-OC_(?)H_4S)^(2-)]was synthesized by the reaction of MoOCl_3(THF)_2 and Na_2mp in EtOH and crystallized in monoclinic space group P2_(?)/n with crystal data:a=13.910(3),b=23.554(3),c=12.558(2)(?),β=105.20(2)°,Z=4,D_o=1.455g/ cm^3,final R=0.077 for 5325 reflections[I>3σ(I)].The two[Mo(O)mp]^+ moicties are bridged by one 1,2-bidentate ligand mp^(2-) with exceedingly small bite angle(69.0°)and bite distance (2.70(?))and by a methoxy group.The structure can be interpreted as two distorted octahedra around the Mo atoms sharing a face.Attempts have been made to provide structural informa- tions for the syntheses of modelling compounds of FeMoco by comparing the Mo—O and Mo—S bond distances of o-mercaptophenolate ligated compounds to those of the molybdenum site of nitrogenase.

Influence of hydrothermal temperature on structure and microstructure of boehmite

Boehmites(Al2O3·xH2O)were hydrothermally prepared from aluminum alkoxide.The effect of temperature on preparation was studied in the range of 100-180℃.The XRD analysis shows that with temperature increasing,the transformation of pseudo-boehmite into well-crystallized boehmite takes place.The micro-morphologies change also from irregular clew to thin cubic platelets.From the mass loss of the samples prepared at different temperatures,the value of x is estimated to vary between 1.06 and 1.67.γ-Al2O3 obtained by subsequent calcination of boehmite at 600℃is also characterized by XRD and its morphology remains unchanged.

Photocatalytic degradation of PCP-Na with TiO_2 photocatalysis loaded with platinum

Titanium dioxide(TiO 2) samples of different crystal forms were prepared by hydrolysis tetrabutyl titanate in various water to alkoxide ratios and sintering the hydrolysis product at different temperatures. The photocatalysts coated on hollow glass beads and loaded with platinum varying from 0.2% to 2.4% by weight.The photocatalytic degradation rate of sodium pentachlorophenolate (PCP-Na) depends on the preparing conditions such as: sintering temperatures, water to alkoxide ratios( R ), platinum content and the size. The proper conditions of preparation photocatalysts are as follows: the ratio of TiO 2 : sodium silicate : hollow glass beads : platinum is 10:5:20:0.15(w/w), R is 100, sintering temperature is 650℃, and the size of hollow glass is 0.5-1 mm. Under these conditions, the ratio between acatase and rutile of the photocatalyst is 2:1, and the photocatalytic activity is high.

Effect of Synthetic Parameters on Synthesis of Magnesium Aluminum Spinels

In this work, the magnesium aluminum spinel (MgAl2O4) was prepared by Mg and Al as precursors through a method of sol-gel subsequent with high temperature calcination. The wide range of synthetic conditions, including organic alcohols, ammonia content, dispersant, alkoxide concentration, hydrolysis time, hydrolysis temperature and calcination temperature were screened over as-prepared samples. This work provides a necessary experimental basis for the synthesis of MgAl2O4 with uniform particle size of spherical structure, which has a potential to be used in many industrial and military applications.

Effect of Constituent Core-sizes on Microstructure and Dielectric Properties of BaTiO_3@(0.6BaTiO_3-0.4BiAlO_3) Core-Shell Material

The fundamental characteristics of varied initial core-sizes of Ba Ti O3（BT） and its influential role on the morphology and dielectric properties of Ba Ti O3@0.6 Ba Ti O3-0.4 Bi Al O3（BT@0.6 BT-0.4 BA） ceramic samples were studied. Alkoxide sol-precipitation method was adopted as revised chemical route to synthesize the constituent ＂core＂ BT powders in a dispersed phase, whereas the distinctive initial nano-sized particles were affected by the pre-calcination temperatures（600-900 ℃）.The microstructure of the uncoated BT ceramics revealed an exaggerated grain growth with an optimized dielectric constant（ε（max） 〉9 000） whilst the coated ceramics behaved otherwise（grain growth inhibited） when sintered at an elevated temperature. Regardless of the previously studied solubility limit（about 0.1%） of BT-BA samples, BT@0.6 BT-0.4 BA maintained a maximum dielectric constant（ε（max）） ranging from 1 592 to 1 708 and tan δ less than 2% under a unit mole ratio at room temperature. In view of all these analyses, the initial nanometer sizes of the as-prepared BT-core powders combined with the increase effect of cation substitutions of Bi^（3＋） and Al^（3＋） in the shell content, induced the diffuse transition phase of BT@0.6 BT-0.4 BA composition.

Synthesis, Crystal Structure of [(MeC_5H_4)_2Ln(μ-OCH_2CH_2NMe_2)]_2 (Ln=Sm, Y, Nd) and Their Catalytic Activity for Ring-Opening Polymerization of ε-Caprolactone

Reaction of (MeC 5H 4) 3Ln with HOCH 2CH 2NMe 2 in tetrahydrofuran(THF) gives the new complexes [(MeC 5H 4) 2Ln(μ OCH 2CH 2NMe 2)] 2 (Ln=Sm, Y, Nd) with nitrogen functionalized μ alkoxide ligand. The complexes were characterized by elemental analysis and IR, and [(MeC 5H 4) 2Sm(μ OCH 2CH 2NMe 2)] 2 was structurally characterized by the X ray diffraction to be a dimer formed by two unsymmetric oxygen bridges. The complex has a tricyclic skeleton with the additional two Sm-N bonds via intramolecular coordination of OCH 2CH 2NMe 2. The coordination number of the central metal Sm is nine. The title complexes show good catalytic activity for ring opening polymerization of ε caprolactone.

Ethylene glycol aluminum as a novel catalyst for the synthesis of poly(ethylene terephthalate)

Ethylene glycol aluminum was prepared efficiently and characterized by FT-IR and NMR.It exhibited higher catalytic activity and had profitable effect than titanium glycolate and ethylene glycol antimony for the synthesis of poly（ethylene terephthalate） （PET）.It was only used as polycondensation catalyst because it was sensitive to water.For this catalyst,the degree of esterification of the theoretical amount of water was produced up to 95%at 260℃,while the intrinsic viscosity and content of terminal carboxyl groups of the corresponding PET polyester,polymerized at 280℃,70 Pa for 39 min,was 0.87 dL/g and 23.0μmol/g,respectively. Ethylene glycol aluminum was a promising catalyst for the synthesis of PET polyester.

Lanthanide Complexes for Oligomerization of Phenyl Isocyanate

A series-of lanthanide complexes including (Ind)(3)Sm(THF) (1), [(MeCP)(2)Sm(mu-SPh)(THF)](2),(2), [(MeCp)(2)Y(mu-O-i-Pr)](2) (3), (MeCp)(3)Sm.THF (4), Sm(SPh)(3) (hmpa)(3) (5), [(MeCp)(2)Y(mu-OCH2CF3)](2) (6) and (CF3CH2O)(3)Y(THF)(3) (7) were synthesized and they have good activity for the oligomerization of phenyl isocyanate. Among-them 5 shows,the highest activity. The conversion is as high as 96.2%, with 1/2500 of the molar ratio of cat. / PhNCO. The main components in oligomer were characterized to be a cyclodimer and a cyclotrimer. The ratio of cyclodimer,to cyclotrimer depends on the lanthanide complexes:used. 7 gave 85.2% cyclotrimer with 1/300 of the molar ratio of cat./PhNCO at 40 V for 0.5 h, while 5 gave 77.6% cyclodimer with 1/300 of the molar ratio of cat. /PhNCO at 40 degreesC for 4 h.

Lanthanocene Diolate Complexes: Synthesis, Structures and Catalytic Property for ε-Caprolactone Polymerization

Reaction of LnCl3 first with three equivalent of C5H5Na in THF,then with one equivalent of N-phenyldiethanolamine in THF-DME afforded complexes of{[(C_(5)H_(5))Ln(μ-OCH_(2)CH_(2))_(2)N(C_(6)H_(5))]4(μ_(4)-C_(l))}[Na(DME)_(4)](Ln=Sm(1),Yb(2)),being characterized by infrared spectra,elemental analyses and X-ray crystallography.They are ionic pair compounds.The anionic part is a cluster,which can be viewed as a cyclic tetramer with four(C5H5)Ln units bridged by four pairs of OR groups,forming a pinwheel structure.Both the complexes can catalyze the ring-opening polymerization ofε-caprolactone under mild conditions,and complex 1 is more active than complex 2.The polymerization accords with one order reaction kinetics for monomer concentration.The molecular weight increases with the yield increasing,and the molecular weight distribution is rather narrow(1.19<PDI<1.29).

An Innovative Self-formation Strategy to Hierarchically Micro-meso-Macroporous Functional Structures for Living Materials

1 Results Facing the important global warming,the exhaustion of crude materials and oil,the super-consumption of energy and the recent and constant sharp increase in the price of crude oil,new materials with advanced properties and multi-functionality can be once again the driving force and the motor to find some issues of these important challenges of our modern society and human life.Recent interest has been devoted to the development of synthesis and processing procedures for preparing porous materia...