Preparation of a Novel NH2 + Ion Implantation Modified Electrode and Its Study of the Electrochemical Behavior of Hemoglobin

Abstract

A novel functional electrode was obtained by implanting NH₂ ⁺ into ITO film (NH₂/ITO) for the first time. The NH₂/ITO surface showed a better affinity to gold nanoparticles than bare ITO. Gold nanoparticles were deposited on the surface of NH₂/ITO electrode (Au/NH₂/ITO). The Au/NH₂/ITO and NH₂/ITO electrodes were used to observe the electrochemical behavior of Hemoglobin (Hb) immobilized on the electrodes surfaces. The peak current value of Hb immobilized on NH₂/ITO increased compared with on bare ITO while peak current value of Hb immobilized on Au/NH₂/ITO increased compared with on Au/ITO. Linkage between the ‐NH₂ implanted into the ITO film and the ‐COOH of Hb was thought to be the reason for the increase of active Hb coverage on NH₂/ITO compared with bare ITO. Increase of active Hb coverage on Au/NH₂/ITO compare with Au/ITO was attributed to the different amount of gold nanoparticles deposited. Results showed the novel NH₂/ITO and Au/NH₂/ITO electrodes exhibited good stability, reproducibility besides selectivity and sensitivity. The electrode process of Hb immobilized on Au/NH₂/ITO was quasi‐reversible with adsorption. The electrode reaction rate constant k_s and other related constants were determined. X‐ray photoelectron spectroscopy (XPS), field‐emission scanning electron microscopy (FE‐SEM), and impedance spectra were used to characterize the different surfaces.     

Kinetics of the decomposition of calcium carbonate in the presence of Bi2O3

Former studies concerning the formation of the compounds in the pseudobinary systems of Bi₂O₃-MO type (M =Ca, Sr, Ca+Sr) have shown that the reaction which occurs with the highest rate is that between Bi₂O₃ and CaO. In the present work CaCO₃ was used as CaO source. We carried out an investigation of the thermal decomposition of CaCO₃ in the presence of Bi₂O₃ in comparison with the decomposition of pure CaCO₃.The presence of Bi₂O₃ exerts a complex influence on the CaCO₃ decomposition acting on the nucleation as well as on the diffusion of CO₂. The decomposition of the samples with low Bi₂O₃ content follows the mechanism of a contracting sphere. A change from surface nucleation to bulk nucleation is recorded for higher amounts of Bi₂O₃.     

Calorimetric study of the adsorption of air pollutants on alumina-supported tin and gallium oxides

The differential enthalpies of adsorption of air pollutants such as SO₂, NO₂, NO on aluminasupported tin and gallium oxides were measured by calorimetry coupled with isothermal volumetry. Whatever the amount of tin or gallium on alumina, the enthalpies of adsorption of SO₂ at low coverage were of the same order of magnitude or up to 50 kJ/mol lower than those of the support. The amount of SO₂ adsorbed decreased with increasing SnO₂ loading and increased with increasing Ga₂O₃ loading on the alumina. The differential enthalpies of adsorption of NO₂ are close to those on the support whatever the amount of tin or gallium (around 120–130 kJ/mol). NO is only reversibly adsorbed on the samples. The calorimetric data of ammonia adsorption are given for comparison.     

Effect of intercalated alkylammonium on cation exchange properties of H2Ti3O7

Cation exchange was studied on alkylammonium intercalated H₂Ti₃O₇ in comparison with H₂Ti₃O₇ itself. Alkylammonium exchanged for proton in advance made it possible for alkali and alkaline earth metal ions to be taken up into H₂Ti₃O₇ in chloride solution. Only alkylammonium was exchanged with hydrated alkali and alkaline earth metal ions. In hydroxide solution, proton was exchanged with alkali metal ions as well as alkylammonium ion. Dependence on pH and preference on ion exchange were affected by the previous uptake of alkylammonium into H₂Ti₃O₇.     

Catalytic effects of six inorganic compounds on pyrolysis of three kinds of biomass

Six inorganic compounds, i.e., Na₂CO₃, NaOH, NaCl, Na₂SiO₃, TiO₂ and HZSM-5, have been investigated with regard to their catalytic effects on pyrolysis of three biomass species, i.e., pine wood, cotton stalk and fir wood by thermal analysis experiments. The results show that Na₂CO₃, NaOH, Na₂SiO₃ and NaCl made devolatilization occur at lower temperature regions in the pyrolysis of the three kinds of biomass, whereas TiO₂ and HZSM-5 made that occur at higher temperature regions in the pyrolysis of cotton stalk and had no obvious effects on pyrolysis temperatures of pine wood and fir wood. The basic catalysts NaOH, Na₂CO₃ and Na₂SiO₃ decreased the maximum weight loss rates while NaCl and HZSM-5 increased them and TiO₂ had no obvious effects on them. The four sodium compounds made pyrolysis of the three kinds of biomass more exothermic, which might be due to more char formation, whereas TiO₂ and HZSM-5 had minor effects on reaction heat. The catalytic effects in all aspects were roughly correlated with one another and their relationship with the basicity and acidity of the catalysts were preliminarily described and analyzed.     

Catalytic activity of solid solutions of nickelous and zinc oxides

Summary A comparison of the change in the rules of chemisorption of gas-acceptors and donors of electrons with catalytic activity for processes with gases of the same type showed that the change in the catalytic properties of NiO and ZnO and their solid solutions may be explained by the effect of dissolved oxides Li₂O, Ga₂O₃, Fe₂O₃, etc., on chemisorption. The change in chemisorption is considered to be connected with the effect of cations with an anomalous charge in the lattice points on the statistics of the active centers on the surface.     

UV‐Assisted Removal of Inactive Peroxide Species for Sustained Epoxidation of Cyclooctene on Anatase TiO2

Epoxidation of olefins with H₂O₂ is one of the most important reactions in organic synthesis. We found that anatase TiO₂ can be a good catalyst for the epoxidation of cyclooctene with H₂O₂ at room temperature. However, the catalyst deactivated quickly in the presence of excess amount of H₂O₂ because of the formation of inactive side‐on Ti‐η²‐peroxide species on the surface of TiO₂, the presence of which was confirmed by isotope‐labelled resonance UV Raman spectroscopy and kinetics studies. Interestingly, the epoxidation reaction could be dramatically accelerated under irradiation of UV light with λ≥350 nm. This phenomenon is attributed to the photo‐assisted removal of the inactive peroxide species, through which the active sites on the surface of anatase TiO₂ are regenerated and the catalytic epoxidation of cyclooctene with H₂O₂ is resumed. This finding provides an alternative for sustained epoxidation reactions on TiO₂ at room temperature. Moreover, it also has significant implications on the deactivation pathway and possible solutions in Ti‐based heterogeneous catalysis or photocatalysis.     

Influence of the chemical and textural properties of k2cr2o7 supported on solids,in the oxidation of cholesterol

Several K₂Cr₂O₇ supported reagents on inert solids have been obtained by deposition of K₂Cr₂O₇ on different solids.A1PO ,BPO and solid mixtures BPO -A1PO are used as supports. The K₂Cr₂O₇ is deposited on solid as large crystals detected by an X-ray diagram in the Cr50 and Cr25 series giving solids with very low surface areas.The number of acid and oxidizing sites is dtermined.Solids supports with small surface areas and large pore diameter give K₂Cr₂O₇ supported reagents with higher activity than those obtained from solids with high surface areas and large pores.     

Study of the performances of an oxygen carrier: Experimental investigation of the binder's contribution and characterization of its structural modifications

The aim of this work is to investigate the contribution of the binder (NiAl₂O₄) on the performances of the oxygen carrier NiO/NiAl₂O₄. To this purpose, oxidation/reduction cycles have been performed in a fixed bed reactor using CO as a fuel. The results reveal that the binder can react with the fuel to form CO₂, and that its total reduction capacity increases with temperature. XRD characterizations performed on the binder (on the fresh and after several cycles) show a shift of the diffraction peaks of NiAl₂O₄ toward the ones of γ-alumina, which can be attributed to a progressive decomposition of NiAl₂O₄ to alumina and NiO.     

Kinetics of reactions of 2,2′-bipyridyltetracarbonylmolybdenum(0)

Summary Kinetic results are presented for reaction of Mo(CO)₄(bipy) with cyanide in several nonaqueous solvents and in DMSO-H₂O mixtures, with methoxide, and with azide; for reaction of Mo(CO)₄(5-NO₂phen) with cyanide and with methoxide; and for reaction of Mo(CO)₄(phen) and of W(CO)₄(bipy) with cyanide. Solvent effects on the reaction of Mo(CO)₄(bipy) with cyanide are dissected into their initial state and transition state components. Here, and in the dependence of the activation volume for this and related reactions on solvent, the important role played by cyanide solvation is apparent. Preliminary investigations on reactions of compounds of this M(CO)₄(diimine) type with tertiary phosphines, diethyldithiocarbamate, and ether peroxides are described.     

Behavior of manganite electrodes in contact with LSGM electrolyte: the nature of low electrochemical activity

The electrochemical cells with electrodes based on La_0.8Sr_0.2MnO₃ (LSM) and supporting solid electrolytes La_0.88Sr_0.12Ga_0.82Mg_0.18O_2.85 (LSGM) and Ce_0.80Sm_0.20O_1.90 (SDC) were studied comparatively. Characteristics of LSM electrodes and composite electrodes comprising a mixture of LSM and electrolytes of different origins [LSGM, SDC, and Zr_0.82Sc_0.18O_1.91 (SSZ) in the mass ratio of 1:1] were analyzed. It was shown that: 1) the electrode polarization conductivity and the ohmic resistance of the cells with the LSM–LSGM composite electrodes on the LSGM and SDC electrolytes had very similar values, while they were largely different from all the other electrodes, 2) the electrochemical activity of the electrodes on the SDC electrolyte was much higher than on the LSGM electrolyte, and 3) the ohmic resistance of the cells with the SDC electrolyte corresponded to the electrolyte resistance, whereas, the ohmic resistance of the cells with the LSGM electrolyte was much larger than the electrolyte resistance. The obtained results are due to the interaction between the LSM and LSM-containing electrodes with the LSGM electrolyte during sintering, leading to the formation of a product with a very low conductivity.     

An FT-i.r. study of the deposition of Co(CO)3NO on zeolite-Y: influence of the support on the formation of isocyanates

Fourier transform i.r. spectroscopy has been used to study the adsorption and subsequent reactions of Co(CO)₃NO on a sodium zeolite-Y (NAY) and the results have been compared with those obtained previously for deposition on Al₂O₃. The support strongly influences the nature of the evolution of this reaction; whereas isocyanates form easily at room temperature on Al₂O₃, this does not occur on NaY but N₂ is generated instead. However, with both supports, oxidation of the metallic centre occurs with the generation of a dinitrosyl species having a pair of NO bands near 1880 and 1800 cm^-1. For both supports, this oxidation is inhibited if the coadsorption is carried out in the presence of excess CO, and it is accelerated during coadsorption with excess NO. It is suggested that the Lewis acid Al(+III) sites on Al₂O₃ play a pivotal role in the generation of surface nitride leading to isocyanate formation.     

Effect of the modification of ZrO<Subscript>2</Subscript>-containing pillared clay with Pt and Cu atoms on the properties of inorganic complex intermediates in the selective catalytic reduction of nitrogen oxides with propylene according to in situ IR-spectroscopic data

It was found that only bridging and bidentate nitrate complexes were formed on the surface of Pt,Cu/ZrO₂-pillared interlayered clay (ZrO₂-PILC) upon the interaction with a flow of the (0.2% NO + 2.5% O₂)/N₂ mixture, whereas monodentate and nitrosyl complexes were not detected. The concentration of nitrate complexes on Pt,CU/ZrO₂-PILC was higher and the strength of their bond to the surface was weaker than those on unmodified ZrO₂-PILC. Isopropoxide and acetate complexes and coordinatively bound acetone were formed on the surface in the interaction of Pt,Cu/ZrO₂-PILC with a flow of the (0.2% C₃H₆ + 2.5% O₂)/N₂ mixture. The supporting of Pt and Cu onto zirconium dioxide pillars resulted in considerable changes in the concentration and the temperature region of the existence of hydrocarbon surface compounds, as compared with ZrO₂-PILC. Under reaction conditions at relatively low temperatures, isopropoxide and nitrate intermediates on the surface of Pt,Cu/ZrO₂-PILC formed a complex structurally similar to adsorbed dinitropropane. At elevated temperatures, a surface nitromethane complex was formed in the interaction of the acetate complex with nitrate species. The spectrokinetic measurements demonstrated that the apparent rate constants of consumption of nitrate and nitroorganic complexes considerably increased on going from ZrO₂-PILC to Pt,Cu/ZrO₂-PILC. Moreover, the constants of consumption of nitroorganic and nitrate complexes were similar for both of the catalysts. This fact suggests that, on the test catalysts, nitroorganic complexes were reaction intermediates in the selective catalytic reduction of NO_x (NO_x SCR) with hydrocarbons. The found differences in the activation species and thermal stabilities of reactants can explain different activities of ZrO₂-PILC and Pt,Cu/ZrO₂-PILC in the SCR reaction of NO_x with propylene in an excess of oxygen.     

Photoluminescence and FT-IR studies of the dissociative adsorption of H2 on the active ZrO2 catalyst and its role in the hydrogenation of CO

Photoluminescence and FT-IR studies of the adsorption of H₂ on ZrO₂ catalysts have been performdd to clarify the true natuee of active surface sites for the activaiion of H₂ in connection with the CO — H₂ reaction on the catalyst. The results indicate that the coordinatively unsaturated surface sites with different coordination numbers are generated on the surfaces by evacuation at temperatures higher than 600 K. These surface sites of lower coordination play a significant role in the reversible and irreversible dissociative adsorption of H₂ on the active ZrO₂ catalyst. The former seems to act as active hydrogen species for the CO — H₂ reaction to form branched hydrocarbons on the ZrO₂ catalyst.     

制备过程对 Pd-SiW12/SiO2 催化剂在乙烯选择氧化制乙酸反应中催化性能的影响

 采用不同负载顺序或制备过程制备了 Pd-SiW12/SiO2 催化剂, 考察了它们在乙烯直接氧化制乙酸反应中的催化性能. 结果表明, Pd 和 SiW12 的负载顺序与 Pd 负载后的处理条件对 Pd-SiW12/SiO2 催化剂上 Pd 的分散度影响较大, 但对催化剂表面 B 酸量影响不大, 而 Pd 分散度较高时, 相应催化剂活性较高. 将 Pd 和 SiW12 同时负载于 SiO2 上时, 催化剂表现出较高的催化乙烯直接氧化制乙酸反应活性.     

Separation of fat-soluble vitamins by thin-layer chromatography

Summary This paper is dealing with the evaluation of the method for qualitative analyses of fat soluble vitamins by thin-layer chromatography on impregnated starch, cellulose and talc thin layers. Impregnation was carried out with paraffin oil. Complete analyses could be obtained on two plates with two different solvents. Vitamins K₃, K₄ and K₅ were separated with solvent I (water-dioxane-acetone-formaldehyde (85∶20∶15∶25)) whereas the other remain on the start position. Vitamins A-acetate, A-palmitate, K₁, DL-alpha-tocopherol, DL-alpha-tocopherol-acetate, D₂, D₃ were separated with solvent II (acetone-concentrated acetic acid (30∶20)) while K₃, K₄ and K₅ migrate with front. Quick and simple procedures for the preparation of the plates with an impregnated thin layer is given.     

Preparation of Au Nanoparticles on Surface of Two Supports by Adsorption Phase Synthesis

By utilizing adsorption phase synthesis (APS), Au nanoparticles were prepared on the surface of SiO₂ with or without modification by Ni(OH)₂. TEM, XRD, and UV‐vis were employed to characterize the morphology of Au particles on the surface of two kinds of supports. The results showed that the average size of Au particles on the SiO₂ surface modified by Ni(OH)₂ was less than 5 nm. Due to high surface isoelectric point, Au particles formed in the adsorption layer were prone to distribute on the surface of SiO₂ modified by Ni(OH)₂. With content of Ni(OH)₂ in samples increasing, more Au particles with small size appeared on the support surface.     

Copolymerization of ethylene with 1‐hexene over metallocene catalyst supported on complex of magnesium chloride with tetrahydrofuran

The study of ethylene/1‐hexene copolymerization with the zirconocene catalyst, bis(cyclopentadienyl)zirconium dichloride (Cp₂ZrCl₂)/methylaluminoxane (MAO), anchored on a MgCl₂(THF)₂ support was carried out. The influence of 1‐hexene concentration in the feed on catalyst productivity and comonomer reactivity as well as other properties was investigated. Additionally, the effect of support modification by the organoaluminum compounds [(MAO, trimethlaluminum (AlMe₃), or diethylaluminum chloride (Et₂AlCl)] on the behavior of the MgCl₂(THF)₂/Cp₂ZrCl₂/MAO catalyst in the copolymerization process and on the properties of the copolymers was explored. Immobilization of the Cp₂ZrCl₂ compound on the complex magnesium support MgCl₂(THF)₂ resulted in an effective system for the copolymerization of ethylene with 1‐hexene. The modification of the support as well as the kind of organoaluminum compound used as a modifier influenced the activity of the examined catalyst system. Additionally, the profitable influence of immobilization of the homogeneous catalyst as well as modification of the support applied on the molecular weight and molecular weight distribution of the copolymers was established. Finally, with the successive self‐nucleation/annealing procedure, the copolymers obtained over both homogeneous and heterogeneous metallocene catalysts were heterogeneous with respect to their chemical composition. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2512–2519, 2004     

柠檬酸添加方式对Mo-Ni-P/Al_2O_3催化剂加氢活性的影响

以Mo、Ni为活性组分,Al_2O_3为载体,采用不同柠檬酸添加方法制备了Mo-Ni-P/Al_2O_3催化剂.通过氢气程序升温还原(H2-TPR)、X射线衍射(XRD),透射扫描电镜(TEM)、XPS等表征方法研究催化剂的物化性质.结果表明:催化剂经柠檬酸的后处理,改善了载体氧化铝表面羟基基团的分布,促使Mo物种以八面体配位多核聚钼酸的形态存在,有效地减弱了载体与活性金属之间的强相互作用,提高了Mo物种的分散度与硫化度,使得催化剂形成更多"Mo-Ni-S"加氢活性相,提高了催化剂的加氢活性.与其他处理方法相比,柠檬酸后处理的催化剂对VGO具有更高的加氢脱硫、脱氮与芳烃饱和性能.     

Role of oxidizers in the active dissolution and passivation of metals

It was established that addition of hydrogen peroxide to a solution of sulphuric acid leads to acceleration of the active dissolution of chromium and to the shift of its passivation potential in negative direction. Similar data were obtained for Fe-28% Cr alloy in H₂SO₄ solution containing H₂O₂ and for iron in sulphuric acid with K₂Cr₂O₇ additions. The conclusion was made that depending on the potential the molecules of oxygen-containing oxidizers can undergo different transmissions on the surface of the metal, including transformations connected with the direct participation of the oxidizer in the anodic dissolution of the metal or in the building of inhibiting or passivating layers on the metallic surface.