Ni-Co/Mg-Al catalyst derived from hydrotalcite-like compound prepared by plasma for dry reforming of methane

Ni-Co bimetallic catalysts with different Ni/Co content were derived from cold plasma jet decomposition and reduction of hydrotalcite-like compounds containing Ni,Co,Mg and Al,and their catalytic performance was investigated with dry reforming of methane.Experimental results showed that the hydrotalcite-like precursors could be completely decomposed and partly reduced by cold plasma jet,and the Nicontained catalysts exhibited much higher activity than the catalyst without Ni.Especially,the catalyst with Ni/Co ratio of 8/2 achieved not only the highest conversions of 80.3%and 69.3%for CH4 and CO2,respectively,but also the best stability in 100 h testing.The catalysts were characterized by XRD,XPS,TEM and N2 adsorption techniques,and the results showed that the better performance of the 8Ni2Co bimetallic catalyst was attributed to its higher metal dispersion,smaller metal particle size,as well as the interaction effect between Ni and Co,which were brought by the special catalyst preparation method.

Preparation,Characterization,and Catalytical Application of MgCoAl-Hydrotalcite-Like Compounds

MgCoAl-hydrotalcite-like compounds （MgCoAI-HTLcs） were synthesized using the coprecipitation method of variable pH values. The effect of each factor on the preparation of HTLcs was discussed systematically, which included pH values, mole ratios of Mg2＋ to Co2＋, the concentrations of the solution, and the temperature and time of the hydrothermal treatment. Besides, the thermal decomposition of MgCoAI-HTLcs was discussed. X-ray diffraction, thermogravimetric analysis, and FT-IR spectroscopy were performed to characterize the MgCoAI-HTLcs samples. The results showed that when the pH = 7.6-8.5 or 5.5-6.2, atomic ratios of （Mg^2＋＋Co2＋）/Al^3＋ 2 and Mg^2＋/Co^2＋ ranging from 1.00 to 2.00, temperature and time of hydrothermal treatment being 110℃ and 6 h, unique MgCoAI-HTLcs with high crystallinity could be obtained. When the calcination temperature was up to 250℃, the MgO phase was detected coexisting with Al2O3 and MgAl2O4 was highly spreaded on the derived mixed oxides. The synthesis reaction of benzoin methyl ether with methanol and benzaldehyde was chosen to study the catalytic activity of MgCoAI-HTLcs. The catalyst showed high activity and high stability in the synthesis of benzoin methyl ether in the feasible condition.

The Isoelectric Point and the Points of Zero Charge of Fe-Al-Mg Hydrotalcite-like Compounds

The relation of the isoelectric point (IEP) and the point of zero net charge (PZNC) of the hydrotalcite-like compounds was discussed. It was found that the IEP does not equal to the PZNC and the IEP is higher than the PZNC. The structural positive charges existing in the HTlc, which cause the difference between the IEP and the PZNC. The effects of the structural positive charges of the HTlc on its IEP and PZNC are the same as the specific adsorption of metal cations.

Studies on the Synthesis and the Structure of Ferric Aluminum Magnesium Hydrotalcite-like Compounds

The particles of ferric aluminum magnesium hydrotalcite-like compounds (Fe-Al-Mg_HTlc) were synthesized by co-precipitation method. It was found that when n(Fe)/n(Al+Mg+Fe)<0.30 and n(Al)/n(Al+Mg+Fe)<0.30, pure HTlc can be formed; when the molar ratio of Al/ (Fe+Al+Mg)>0.30, Al(OH)3 will emerge; when the molar ratio of Fe/(Fe+Al+Mg) >0.30, the amorphous composition will appear. Hence Fe3+ and Al3+ have no concentration superposition effect on the crystal structure of the samples.

CoMnMgAl Hydrotalcite-like Compounds and their Complex Oxides: Facile Synthesis and FCC SO_x Removal

The X-CoMnMgAl hydrotalcite-like precursors(X-LDHs) were first synthesized by the coprecipitation method using Cl-, CO32-, NO3- and SO42- as the corresponding guest anions, which were further used to prepare X-CoMnMgAl complex oxides(X-LDOs) through calcination. The structure and the surface morphology of the as-prepared samples were characterized by FT–IR, XRD, N2 adsorption-desorption and SEM. These as-prepared X-LDOs could act as sulfur-transfer catalysts for desulfurization. The activity of SOx adsorption and regeneration was evaluated via a self-assembled fixed-bed reactor simulating the conditions found in the fluid catalytic cracking units. These four types of sulfur-transfer catalysts with the same phase but different structure displayed the following order of desulfurization efficiency: CO3-LDO >Cl-LDO >NO3-LDO > SO4-LDO.

Preparation,Characterization and Application of ZnAlLa-Hydrotalcite-Like Compounds

The preparation of ZnAlLa-hydrotalcite-like compounds [ZnAlLa-HTLcs] wasstudied. ZnAlLa-HTLcs were synthesized by a method of variable pH with the raw materials ofZn(NO_3)_2, Al(NO_3)_3, La(NO_3)_3, and NaOH. The eS'ccts of some factors (i.e. pH values, the moleratio of Al^(3+) to La^(3+), temperature and the period of hydrothermal treatment) on thepreparation of HTLcs were discussed systematically. XRD, TG-DTA, FT-IR spectroscopy, and ICP wereperformed to characterize ZnAlLa-HTLcs samples, and the thermal stability of HTLcs was alsodiscussed. It was shown that unique ZnAlLa-HTLcs with high crystallinity can be prepared, under theconditions of pH = 5.5-6.5, n(Zn^(2+))/n(Al^(3+) + La^(3+))=2 and the atomic ratio of La^(3+) toAl^(3+) ranging from 0.07 to 2, hydrothermal treatment at 120 ℃ for 5 h. When the calcination ofthe HTLcs is performed at temperatures above 200 ℃, ZnO phase is detected with Al_2O_3 and La_2O_3spreading on its top. The complex metal oxides derived from ZnAlLa-HTLcs at 500 ℃ have highercatalytic activity and selectivity than those from ZnAl-HTLcs for the esterification of acetic acidwith n-butanol under the same reaction conditions.

Using Kaolinitic Clay for Preparation of a Hydrotalcite-Like Compound

In this study, Mg-Al-CO3 hydrotalcite was synthesized from a kaolinite as natural source aluminium using two simple methods. The first method uses the kaolinite in natural solid state, the second method use the filtrate of the kaolinite after dissolution by acidic solutions. The structure of the materials was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry (DSC) and Brunauer, Emmett, and Teller (BET) measurements.

Removal of Cu（Ⅱ） from CuSO4 Aqueous Solution by Mg-Al Hydrotalcite-like Compounds

Hydrotalcite-like compound （HTlc） with a Mg/AI molar ratio of 2 ： 1 was synthesized by using a coprecipitation method and the sorption removal of Cu（Ⅱ） by the Mg-AI HTlc sample from CuSO4 solution was investigated. It was found that the Mg-AI HTlc showed a good sorption ability for Cu（Ⅱ） from CuSO4 solution, indicating that the use of hydrotalcite-like compounds as promising inorganic sorbents for the removal of heavy metal ions from water is possible. The sorption kinetics and the sorption isotherm of Cu（Ⅱ） on the HTlc obeyed the pseudo-second order kinetic model and Langmuir equation, respectively. The percent removal of Cu（Ⅱ） by the HT1c was strongly dependent on the initial pH of bulk solution. It increased sharply with the increase of initial pH value in the range of 5-7, and was relatively small in the initial pH range of 4-5, while it reached about 100% after initial pH was higher than 7. The presence of AlCl3 might obviously lower the equilibrium sorption amount （qc） of Cu（Ⅱ） on the HTlc. However, the presences of NaCI and MgCl2 might increase the qe. The presences of ligands （citric acid and EDTA） in the studied concentration range might obviously decrease the qe of Cu（Ⅱ） on the HT1c. The removal mechanism of Cu（Ⅱ） cations by HTlc in the presence of SO4^2- anions may be attributed to the surface-induced precipitation of Cu（Ⅱ） hydroxides and the surface complex adsorption by the linking effect of SO4^2- between the HTlc and Cu（Ⅱ） cations, and the removal ability arising from the surface-induced precipitation is much higher than that from the linking effect of SO4^2-.

Thixotropy of Aqueous Suspensions Containing Mg-AI Hydrotalcite-like Compound and Low-substituted Cationic Starch： Comparison between Oscillatory Shear and Thixotropic Loop Measurements

The rheological properties of aqueous suspensions consisting of positively charged aluminum magnesium hydrotalcite-like compound （HTlc） and low-substituted cationic starch （LCS） were investigated. Special emphasis was placed on the thixotropic phenomenon. Thixotropic behavior was investigated by two thixotropic methods： thixotropic loop and oscillatory shear measurements. LCS molecules could be adsorbed onto HTlc particles due to the hydrogen bonding between ether groups or hydroxyl groups of LCS and hydroxyl groups of HTlc. The elastic dynamic response of the HTlc/LCS suspension increased with increasing mass ratio （R） of HTlc and a three-dimensional network structure could be formed in the suspension with higher R value. The thixotropic type of the HTlc/LCS suspension transformed from negative to positive and then to complex thixotropy when R changed from 0 to 0.5. By comparing between the thixotropic results obtained by thixotropic loop and oscillatory shear measurements, it was validated that the thixotropic loop for the suspension showing complex thixotropy had a crossover point.

Novel Co-Mg-Al-Ti-O catalyst derived from hydrotalcite-like compound for NO storage/decomposition

Catalysts of Co1.5Mg1.5/Al0.9Ti0.1O and Co1.5Mg1.5/AlO were successfully prepared by calcinations of corresponding hydrotalcite-like compounds at 800°C for 4 hr. The derived oxides were of spinel phase and a small quantity of Ti substitution did not change the crystal purity. Their catalytic performance for the NO storage/decomposition was investigated. Ti incorporation enhanced the NO decomposition activity while has an opposite effect on the storage capacity of catalyst. In situ FT-IR spectra of the catalysts showed that the final adsorption species on the catalysts was coordinated nitrates/nitrites. In addition, NO storage/decomposition mechanism has been discussed on the basis of these observations.

Preparation and characterization of a novel strong-fluorescent hydrotalcite-like compound (Al-HTLc)

A novel strong-fluorescent hydrotalcite-like compound (Al-HTLc) was synthesized by coprecipitation. In the sample, the content of aluminum(III) in the layers was decreased to a proper value. The Al3+ ions coordinated with 8-hydroxyquinolines (8-HQ) which were dispersed into the anions in the interlayer region. The sample was characterized by XRD, XPS, FT-IR, TG-DSC, UV-Vis, and fluorescence spec- troscopy; its composition and structure were also determined. The results indicate that the sample can emit fluorescence (487 nm) with a strong fluorescence intensity (4.9×105 (a.u.)). The fluorescent lifetime and fluorescence quantum yield of Al-HTLc were measured to be 21.24 ns and 67%, respectively, higher than those of pure 8-hydroxyquinoline aluminum (Alq3). The result of TG-DSC measurement clearly shows the enhanced thermal stability of Al-HTLc compared with that of MgAl-LDH and pure Alq3. Al-HTLc may be used as a novel luminescent functional material.

Compound 3k治疗骨关节炎:调控氧化应激通路改善软骨细胞糖酵解的作用机制

背景:骨关节炎现已被认为是一种代谢性疾病,既往研究表明糖酵解在骨关节炎的发生发展中起重要作用。Compound 3k作为一种新型糖酵解小分子抑制剂,具有抗炎及抗肿瘤等功效,因此可靶向糖酵解,有望为骨关节炎治疗提供新的思路。目的:基于缺氧诱导因子1α/活性氧的氧化应激通路探究Compound 3k在糖酵解过度活跃所导致的骨关节炎中的作用机制。方法:取对数生长期的ATDC5成软骨细胞,用10 ng/mL白细胞介素1β作用24 h诱导骨关节炎体外细胞模型,以CCK-8法检测不同浓度(0.25,0.5,1,2.5,5,10,15μmol/L)Compound 3k的细胞毒性,选出合适浓度进行后续实验。将软骨细胞随机分为对照组、模型组、治疗组,模型组以10 ng/mL的白细胞介素1β诱导,治疗组以Compound 3k预刺激2 h后与白细胞介素1β共培养,用CCK-8法检测各组细胞增殖情况;用ELISA试剂盒检测各组细胞炎症水平;用试剂盒检测各组细胞活性氧、细胞外乳酸脱氢酶及葡萄糖含量;qRT-PCR及Western blot检测相关炎症因子白细胞介素6、肿瘤坏死因子α及糖酵解相关基因葡萄糖转运蛋白1、甘油醛3-磷酸脱氢酶、单羧酸转运蛋白1和缺氧诱导因子1α的表达水平。结果与结论:①与对照组相比,模型组细胞增殖活性下降、糖酵解水平活跃,表现为细胞外乳酸脱氢酶含量增加(P<0.001),葡萄糖含量减少(P<0.001),相关炎症因子白细胞介素6(P<0.0001)及肿瘤坏死因子α(P<0.001),糖酵解相关基因葡萄糖转运蛋白1(P<0.001)、甘油醛3-磷酸脱氢酶(P<0.001)、单羧酸转运蛋白1(P<0.001)及缺氧诱导因子1α(P<0.001)的表达水平均上调,并伴随氧化应激,活性氧过量产生。②与模型组相比,Compound 3k的治疗有效提高细胞增殖活性,抑制过度活跃的糖酵解水平的同时,抑制了骨关节炎软骨细胞炎症(P<0.001)及糖酵解相关基因的表达(P<0.001),且抑制氧化应激,缺氧诱导因子1α的表达水平下调(P<0.0001),活性氧水平下降。③上述结果证实,Compound 3k抑制了白细胞介素1β诱导的软骨细胞炎症,其机制可能与糖酵解及缺氧诱导因子1α/活性氧介导的氧化应激有关。

Synthesis and characterization of a strong-fluorescent Eu-containing hydrotalcite-like compound

A novel strong-fluorescent Eu-containing hydrotalcite-like compound (Eu-HTlc) was synthesized using the coprecipitation method,in which aluminum(III) was partially substituted by Europium (III) in the hydrotalcite-like layers,and thenoyltrifluoroacetone,1,10-phenanthroline were dispersed into the anions in the interlayer region.The sample was characterized by XRD,XPS,FT-IR,ICP,TG-DSC,TEM and fluorescence spectra,and its composition and structure were determined.The results indicated that the sample exhibited a characteristic red light (614 nm).The fluorescent lifetime and fluorescence quantum yield of Eu-HTlc were measured to be respectively 893 -s and 66.44%,higher than those of Eu(III)-thenoyltrifluoroacetone1,10-phenanthroline complex [Eu(TTA)3phen].The result of TG-DSC measurement showed the enhanced thermal stability of Eu-HTlc compared with that of MgAl-LDHs and Eu(TTA)3phen.With excellent photoluminescent property and thermal stability,low contents of rare earth ions and ligands,the Eu-HTlc may become one of the novel fluorescent materials with potential applications.

N2O Decomposition over K-Ce Promoted Co-M-AI Mixed Oxide Catalysts Prepared from Hydrotalcite-like Precursors

A series of mixed oxide catalysts with different composition of Co-M-Al and Co-M-Ce- Al （M=Zn, Ni, Cu） were prepared by co-precipitation method from hydrotalcite-like compounds. The experimental results revealed the catalytic activity of Co-Ni-Al is slightly higher than that of Co-Zn-Al and much higher than that of Co-Cu-Al for direct decomposition of N2O. Moreover, addition of small amounts of Ce02 improved the catalytic activity signif- icantly and made the decomposition temperatures at which the N2O conversion was 50% and 90% （T50 and Tgo） both decreased 80 ℃ than those of Co-M-Al catalysts without CeO2 added. Further, potassium-load also promoted the catalytic activity, and the decomposi- tion temperatures of T50 and T90 both decreased approximately 50 ℃. It is significant for decomposing N2O from industries and reducing carbon emission from atmosphere.

Hydrotalcite-like Materials as Catalyst for the Conjugate Addition of Amines to Electron Deficient Alkenes

The novel efficient procedure has been developed for the conjugate addition of amines to electron deficient alkenes.A series of hydrotalcite-like materials were synthesized as catalyst for the conjugate addition of amines and alkenes.After optimizing the reaction conditions,ZnAl-LDHs (3:1) was chosen as the best catalyst for the reaction.The results showed that the catalyst worked very well for the conjugate addition of amines to electron deficient alkenes with the excellent yields in several minutes.Operational simplicity,no solvent,low cost of the catalyst,high yields,reusability,excellent chemoselectivity,wide applicability are the key features of this method.

Comparative evaluation of commercial Douchi by different molds:biogenic amines,non-volatile and volatile compounds

To provide new insights into the development and utilization of Douchi artificial starters,three common strains(Aspergillus oryzae,Mucor racemosus,and Rhizopus oligosporus)were used to study their influence on the fermentation of Douchi.The results showed that the biogenic amine contents of the three types of Douchi were all within the safe range and far lower than those of traditional fermented Douchi.Aspergillus-type Douchi produced more free amino acids than the other two types of Douchi,and its umami taste was more prominent in sensory evaluation(P<0.01),while Mucor-type and Rhizopus-type Douchi produced more esters and pyrazines,making the aroma,sauce,and Douchi flavor more abundant.According to the Pearson and PLS analyses results,sweetness was significantly negatively correlated with phenylalanine,cysteine,and acetic acid(P<0.05),bitterness was significantly negatively correlated with malic acid(P<0.05),the sour taste was significantly positively correlated with citric acid and most free amino acids(P<0.05),while astringency was significantly negatively correlated with glucose(P<0.001).Thirteen volatile compounds such as furfuryl alcohol,phenethyl alcohol,and benzaldehyde caused the flavor difference of three types of Douchi.This study provides theoretical basis for the selection of starting strains for commercial Douchi production.

Effect of different drying methods on the amino acids,α-dicarbonyls and volatile compounds of rape bee pollen

The significant demand for high quality food has motivated us to adopt appropriate processing methods to improve the food nutritional quality and flavors.In this study,the effects of five drying methods,namely,pulsed vacuum drying(PVD),freeze drying(FD),infrared drying(IRD),hot-air drying(HAD)and sun drying(SD)on free amino acids(FAAs),α-dicarbonyl compounds(α-DCs)and volatile compounds(VOCs)in rape bee pollen(RBP)were determined.The results showed that FD significantly released the essential amino acids(EAAs)compared with fresh samples while SD caused the highest loss.Glucosone was the dominantα-DCs in RBP and the highest loss was observed after PVD.Aldehydes were the dominant volatiles of RBP and SD samples contained more new volatile substances(especially aldehydes)than the other four drying methods.Comprehensively,FD and PVD would be potential methods to effectively reduce the quality deterioration of RBP in the drying process.

Numerical modeling of fracture propagation of supercritical CO_(2)compound fracturing

The exploitation of shale gas is promising due to depletion of the conventional energy and intensification of the greenhouse effect.In this paper,we proposed a heat-fluid-solid coupling damage model of supercritical CO_(2)(SC-CO_(2))compound fracturing which is expected to be an efficient and environmentally friendly way to develop shale gas.The coupling model is solved by the finite element method,and the results are in good agreement with the analytical solutions and fracturing experiments.Based on this model,the fracture propagation characteristics at the two stages of compound fracturing are studied and the influence of pressurization rate,in situ stress,bedding angle,and other factors are considered.The results show that at the SC-CO_(2)fracturing stage,a lower pressurization rate is conducive to formation of the branches around main fractures,while a higher pressurization rate inhibits formation of the branches around main fractures and promotes formation of the main fractures.Both bedding and in situ stress play a dominant role in the fracture propagation.When the in situ stress ratio(δ_(x)/δ_(y))is 1,the presence of bedding can reduce the initiation pressure and failure pressure.Nevertheless,it will cause the fracture to propagate along the bedding direction,reducing the fracture complexity.In rocks without bedding,hydraulic fracturing has the lengthening and widening effects for SC-CO_(2)induced fracture.In shale,fractures induced at the hydraulic fracturing stage are more likely to be dominated by in situ stresses and have a shorter reorientation radius.Therefore,fracture branches propagating along the maximum principal stress direction may be generated around the main fractures induced by SC-CO_(2)at the hydraulic fracturing stage.When the branches converge with the main fractures,fracture zones are easily formed,and thus the fracture complexity and damage area can be significantly increased.The results are instructive for the design and application of SC-CO_(2)compound fracturing.

Role of methoxy and C_(α)-based substituents in electrochemical oxidation mechanisms and bond cleavage selectivity of β-O-4 lignin model compounds

In order to better understand the specific substituent effects on the electrochemical oxidation process of β-O-4 bond, a series of methoxyphenyl type β-O-4 dimer model compounds with different localized methoxyl groups, including 2-(2-methoxyphenoxy)-1-phenylethanone, 2-(2-methoxyphenoxy)-1-phenylethanol, 2-(2-methoxyphenoxy)-1-(4-methoxyphenyl)ethanone, 2-(2-methoxyphenoxy)-1-(4-methoxyphenyl)ethanol, 2-(2,6-dimethoxyphenoxy)-1-(4-methoxyphenyl)ethanone, 2-(2,6-dimethoxyphenoxy)-1-(4-methoxyphenyl)ethanol have been selected and their electrochemical properties have been studied experimentally by cyclic voltammetry, and FT-IR spectroelectrochemistry. Combining with electrolysis products distribution analysis and density functional theory calculations, oxidation mechanisms of all six model dimers have been explored. In particular, a total effect from substituents of both para-methoxy(on the aryl ring closing to Cα) and Cα-OH on the oxidation mechanisms has been clearly observed, showing a significant selectivity on the Cα-Cβbond cleavage induced by electrochemical oxidations.

Preparation of lactic acid bacteria compound starter cultures based on pasting properties and its improvement of glutinous rice flour and dough

The effects of 5 lactic acid bacteria(LAB)fermentation on the pasting properties of glutinous rice flour were compared,and suitable fermentation strains were selected based on the changes of viscosity,setback value,and breakdown value to prepare LAB compound starter cultures.The results revealed that Latilactobacillus sakei HSD004 and Lacticaseibacillus rhamnosus HSD005 had apparent advantages in increasing the viscosity and reducing the setback and breakdown values of glutinous rice flour.In particular,the compound starter created using the two abovementioned LAB in the ratio of 3:1 had better performance than that using a single LAB in improving the pasting properties and increasing the water and oil absorption capacity of glutinous rice flour.Moreover,the gelatinization enthalpy of the fermented samples increased significantly.For frozen glutinous rice dough stored for 28 days,the viscoelasticity of frozen dough prepared by compound starter was better than that of control dough,and the freezable water content was lower than that of control dough.These results indicate that compound LAB fermentation is a promising technology in the glutinous rice-based food processing industry,which has significance for its application.