HAXPES （hard X-ray photoelectron spectroscopy） is a powerful emerging instrument in surface analysis. It extended the photoelectron energy range up to 15,000 eV and opened the possibility to study much thicker films...HAXPES （hard X-ray photoelectron spectroscopy） is a powerful emerging instrument in surface analysis. It extended the photoelectron energy range up to 15,000 eV and opened the possibility to study much thicker films, buried layers and bulk electronic properties. In order to study these features, data for the electron IMFP （inelastic mean free path） at these energies is needed. To date, only calculated IMFP are available at energies above 5,000 eV and therefore experimental validation of these calculations are essential. In this paper, a new approach for using the HAXPES spectra is presented. This approach, treats the attenuated part of the electron spectrum as a whole to calculating the average electron energy loss. This average electron energy loss is the result of inelastic collisions in the material and hence, carry with it information about the electron transport poses. Carbon layers with thicknesses between 20 and 75 nanometer deposited over copper substrate were used to test this approach at the Spanish beam-line （Spline） in the ESRF （European synchrotron radiation facility）. The measured results showed good agreement with the predictions of the multiple inelastic scattering theory. In addition, an algorithm for the experimental evaluation of electron IMFP, using the measured energy loss, is proposed.展开更多
Nd2O3 doped BaTiO3ceramics（the additive content was respectively 0.001, 0.002, 0.003, 0.005, 0.01 molar ratio）were prepared by Sol-Gel method to study their dielectric characteristics and electric conductivities thr...Nd2O3 doped BaTiO3ceramics（the additive content was respectively 0.001, 0.002, 0.003, 0.005, 0.01 molar ratio）were prepared by Sol-Gel method to study their dielectric characteristics and electric conductivities through X-ray photoelectron spectrum （XPS）. The results showed that the dielectric characteristics of Nd2O3 doped BaTiO3 ceramics were improved by doping. When Nd2O3 content was 0.003 mol, the results were even better, the dielectric constant was increased, the dielectric loss was decreased, the Curie-temperature （Tc） was 110 ℃, and the frequency characteristic was also good. The resistivity of Nd2O3 doped BaTiO3 ceramics was lower than that of pure BaTiO3 ceramics, when Nd2O3 content was 0.001 mol,the resistivity was （2.364×）108 Ω·m, the smallest. The grain resistance of Nd2O3 doped BaTiO3 ceramics exhibited NTC effect, but the grain boundary resistance showed PTC effect, and the grain boundary resistance was larger than that of the grain resistance, so the PTC effect originated from the grain boundary. The analysis of the element binding energy through X-ray photoelectron spectrum were indicated that the quantivalence of Ba2+and Ti4+in Nd2O3 doped BaTiO3 ceramics was variable, and resulted in the improvement of the conductibility of BaTiO3 ceramics.展开更多
Antibacterial activity of boron-doped TiO2(B/TiO2) nano-materials under visible light irradiation and in the dark was investigated. A simple sol-gel method was used to synthesize TiO2 nano-materials. X-ray diffraction...Antibacterial activity of boron-doped TiO2(B/TiO2) nano-materials under visible light irradiation and in the dark was investigated. A simple sol-gel method was used to synthesize TiO2 nano-materials. X-ray diffraction pattern of B/TiO2 nano-materials represents the diffraction peaks relating to the crystal planes of TiO2(anatase and rutile). X-ray photoelectron spectroscopy result shows that part of boron ions incorporates into TiO2 lattice to form a possible chemical environment like Ti O B and the rest exist in the form of B2O3. The study on antibacterial effect of B/TiO2 nano-materials on fungal Candida albicans(ATCC10231), Gram-negative Escherichia coli(ATCC25922) and Gram-positive Staphylococcus aureus(ATCC6538) shows that the antibacterial action is more significant on Candida albicans than on Escherichia coli and Staphylococcus aureus. Under visible light irradiation, the antibacterial activity is superior to that in the dark.展开更多
The effect of dolomite with different particle size fractions on hematite flotation was studied using sodium oleate as collector at p H of about 9. The effect mechanism of dolomite on hematite flotation was investigat...The effect of dolomite with different particle size fractions on hematite flotation was studied using sodium oleate as collector at p H of about 9. The effect mechanism of dolomite on hematite flotation was investigated by means of solution chemistry, ultraviolet spectrophotometry(UV), inductively coupled plasma atomic emission spectrometry(ICP-AES) and X-ray photoelectron spectroscopy(XPS). It is observed that dolomite with different size fractions has depressing effect on hematite flotation using sodium oleate as collector, and dolomite could be the "mineral depressant" of hematite using sodium oleate as collector. The reasons for that are concerned with sodium oleate consumption and the adsorption onto hematite of dissolved species of dolomite.展开更多
Infrared(IR)absorption spectroscopy has been widely used for dynamic characterization of catalysts and mechanism of catalytic reactions.However,due to the strong infrared absorption of heterogeneous catalysts(mainly o...Infrared(IR)absorption spectroscopy has been widely used for dynamic characterization of catalysts and mechanism of catalytic reactions.However,due to the strong infrared absorption of heterogeneous catalysts(mainly oxides,or supported metal and metal oxides,etc.)below 1200 cm^(-1),and the intensity of regular infrared light source rapidly decays at low-wavenumber range,most in-situ infrared spectroscopy studies are limited to the detection of surface adsorbates in the range of 4000-900 cm^(-1).The change of catalytically active component itself(M-O,M-M bond,etc.,1200-50 cm^(-1))during the reaction is hard to be tracked under reaction conditions by in-situ IR.In this work,a home-made in-situ IR reactor was designed and a sample preparing method was developed.With such progresses,the changes of reactants,products,surface adsorbates,and catalysts themselves can be measured under the same reaction conditions with a spectral range of 4000-400 cm^(-1),providing a new opportunity for in-situ characterization of heterogeneous catalysis.CO oxidation on Pd/SiO_(2) and Cu/SiO_(2) catalysts were taken as examples,since both the two catalytic systems were extensively used commercially,and moreover reduction and oxidation of palladium and copper occur during the examined reaction conditions.The characteristic bands of Pd^(2+)-O(670,608 cm^(-1)),Cu^(+)-O(635 cm^(-1))and Cu^(2+)-O(595,535 cm^(-1))were observed by IR,and the changes during CO oxidation reaction were successfully monitored by IR.The oxidation/reduction of palladium and copper were also confirmed by ex-situ XPS.Moreover,Pd^(0) in Pd/SiO_(2) and Cu^(+)in Cu/SiO_(2) were found as the thermal dynamically stable phases under the examined conditions for CO oxidation.展开更多
Carbonaceous catalysts are potential alternatives to metal catalysts. Graphene has been paid much attention for its high surface area and light weight. Here, hydrogenated graphene has been prepared by a simple gamma r...Carbonaceous catalysts are potential alternatives to metal catalysts. Graphene has been paid much attention for its high surface area and light weight. Here, hydrogenated graphene has been prepared by a simple gamma ray irradiation of graphene oxide aqueous suspension at room temperature. Transmission electron microscopic, element analysis, X-ray photoelectron spectroscopy, and UV-Vis spectrophotometer studies verified the hydrogenation of graphene. The as-prepared hydrogenated graphene can be used as a metal-free carbonaceous catalyst for the Fenton-like degradation of organic dye in water.展开更多
Pickling sludge generated during the neutralization of pickling wastewater with calcium hydroxide in stainless steel pickling process was characterized using X-ray fluorescence spectrometry, X-ray diffractometry, scan...Pickling sludge generated during the neutralization of pickling wastewater with calcium hydroxide in stainless steel pickling process was characterized using X-ray fluorescence spectrometry, X-ray diffractometry, scanning electron microscopy, thermogravimetry and differential scanning calorimetry, etc. The major compositions of pickling sludge are CaF2, CaSO4, Me（OH）, （M： Fe, Cr, Ni）, and the content of CaF2 is high in the sludge. The melting point of pickling sludge is about 1350℃ and the viscosity is about 0.14 Pa.s at 1450 ℃, which are comparatively lower than those of normal refining slag. After heat treatment, the contents of sulfur and fluorine in the pickling sludge were reduced, confirming the thermal decomposition of sulfate in the sludge. Fluorine in the sludge is reduced by the gaseous SiF4 and A1F3 generated through the reactions of CaF2 with SiO2 and Al2O3. The preliminary results from the reduction test indicate that the sulfur content in the steel is not affected by the presence of sulfur in the sludge. The recovery of nickel is about 40%, and the chromium content changes marginally due to the protective atmosphere under the reduction condition of chromic oxide. The pickling sludge is a potential auxiliary material for the production of stainless steel.展开更多
The aim of this paper is to analyze the change in the active structure of lignite during the process of lowtemperature oxidation by constructing a molecular structure model for lignite. Using quantum computation combi...The aim of this paper is to analyze the change in the active structure of lignite during the process of lowtemperature oxidation by constructing a molecular structure model for lignite. Using quantum computation combined with experimental results of proximate analysis, ultimate analysis, Fourier transform infrared spectroscopy(FTIR) and X-ray photoelectron spectroscopy(XPS), a structural model for the large molecular structure was constructed. By analyzing the bond lengths in the model molecule, the evolution law for the active structure of lignite was predicted for the process of low-temperature oxidation. In low-temperature oxidation,alkanes and hydroxyls are the primary active structures observed in lignite, though ether may also react. These active functional groups react with oxygen to release heat, thereby speeding up the reaction between coal and oxygen. Finally, the content of various functional groups in the process of lignite low-temperature oxidation was analyzed by infrared analysis, and the accuracy of the model was verified.展开更多
The silk sericin is the main residue in silk production and it is found to be a low cost and efficient bio-sorbent. In this study, sericin was characterized with various techniques including SEM （scanning electron mi...The silk sericin is the main residue in silk production and it is found to be a low cost and efficient bio-sorbent. In this study, sericin was characterized with various techniques including SEM （scanning electron micro- scope）, XRD, N2 physisorption, FTIR （Fourier transformed infrared spectroscopy） and XPS （X-ray photoelectron spectroscopy）. The nitrogen content of sericin was ca. 8.5 mmol.g-1 according to elemental analysis. Dye adsorption by sericin biosorbent was investigated with the acid yellow （AY）, methylene blue （MB） and copper （II） phthalocyanine-3,4＇4＂4＇＂-tetrasulfonic acid （CuPc） dyes from water. Sericin displayed large capacity for AY andCuPc adsorption with adsorption capacities of respectively 3.1 and 0.35 mmol.g-1, but it did not adsorbed methyl- ene blue dye. This selectivity is due to the basicity of amide groups in seriein biosorbents.展开更多
We developed a novel approach for the preparation of N-doped TiO2 photocatalysts by calcining ammonium titanium oxalate at different temperatures. The structures of N-TiO2 were characterized by powder X-ray diffractio...We developed a novel approach for the preparation of N-doped TiO2 photocatalysts by calcining ammonium titanium oxalate at different temperatures. The structures of N-TiO2 were characterized by powder X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, N2 adsorption-desorption isotherms, X-ray photoelectron spectroscopy, diffuse reflectance UV-Vis spectroscopy, and scanning electron microscope. The N-doped TiO2 photocatalysts calcined below 700 ℃ are the pure anatase phase but that calcined at 700 ℃ is a mixture of anatase and rutile phases. The doped N locates at the interstitial site of TiO2 which leads to the narrowing of bad gap of pure anatase N-TiO2. Among all photocatalysts, N-TiO2 photocatalysts calcined at 600 and 400 ℃ exhibit the best performance in the photodegradation of methyl orange under the UV light and all-wavelength light illuminations, respectively; however, because of the perfect crystallinity and the existence of anatase-rutile phase junctions, N-TiO2 photocatalyst calcined at 700 ℃ exhibits the highest specific photodegradation rate, i.e., the highest quantum yield, under both the UV light and all-wavelength light illuminations.展开更多
In this manuscript, a series of catalyst SG n-[VVO2-PAMAM-MSA] (SG silica gel, PAMAM polyamidoamine, MSA 5-methyl salicylaldehyde, n=0, 1, 2, 3) was prepared and their structures were fully characterized by Fourier tr...In this manuscript, a series of catalyst SG n-[VVO2-PAMAM-MSA] (SG silica gel, PAMAM polyamidoamine, MSA 5-methyl salicylaldehyde, n=0, 1, 2, 3) was prepared and their structures were fully characterized by Fourier transform-infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and inductive coupled plasma emission spectrometer (ICP) etc. XPS revealed that the metal V and SG n-PAMAM-MSA combined more closely after the formation of Schiff base derivatives. Their catalytic activities for oxidation of dibenzothiophene were evaluated using tert-butyl hydroperoxide as oxidant. The results showed that the catalyst SG 2.0-[VVO2-PAMAM-MSA] presented good catalytic activity and recycling time. Meanwhile, the optimal condition for the catalytic oxidation of SG 2.0-[VVO2-PAMAM-MSA] was also investigated, which showed that when the oxidation temperature was 90 °C, time was 60 min, the O/S was 3:1, and the mass content of catalyst was 1%, the rate of desulfurization could reach 85.2%. Moreover, the catalyst can be recycled several times without significant decline in catalytic activity.展开更多
Photocatalytic degradation is one of the most promising remediation technologies in terms of advanced oxidation processes(AOPs) for water treatment. In this study, novel graphitic carbon nitride/titanium dioxide(gC3N4...Photocatalytic degradation is one of the most promising remediation technologies in terms of advanced oxidation processes(AOPs) for water treatment. In this study, novel graphitic carbon nitride/titanium dioxide(gC3N4/Ti O2) composites were synthesized by a facile sonication method. The physicochemical properties of the photocatalyst with different mass ratios of g-C3N4 to Ti O2 were investigated by X-ray diffraction(XRD), scanning electron microscope(SEM), transmission electron microscopy(TEM), N2 sorption, Fourier transform infrared spectroscopy(FT-IR), X-ray photoelectron spectroscopy(XPS), and UV–vis DRS. The photocatalytic performances were evaluated by degradation of methylene blue. It was found that g-C3N4/Ti O2 with a mass ratio of 1.5:1 exhibited the best degradation performance. Under UV, the degradation rate of g-C3N4/Ti O2 was 6.92 and 2.65 times higher than g-C3N4 and Ti O2, respectively. While under visible light, the enhancement factors became 9.27(to g-C3N4) and 7.03(to Ti O2). The improved photocatalytic activity was ascribed to the interfacial charge transfer between g-C3N4 and Ti O2. This work suggests that hybridization can produce promising solar materials for environmental remediation.展开更多
The optimization of electrolytes and the material removal mechanisms for Cu electrochemical mechanical planarization(ECMP)at different pH values including 5-methyl-1H-benzotriazole(TTA),hydroxyethylidenediphosphoric a...The optimization of electrolytes and the material removal mechanisms for Cu electrochemical mechanical planarization(ECMP)at different pH values including 5-methyl-1H-benzotriazole(TTA),hydroxyethylidenediphosphoric acid(HEDP),and tribasic ammonium citrate(TAC)were investigated by electrochemical techniques,X-ray photoelectron spectrometer(XPS)analysis,nano-scratch tests,AFM measurements,and polishing of Cu-coated blanket wafers.The experimental results show that the planarization efficiency and the surface quality after ECMP obtained in alkali-based solutions are superior to that in acidic-based solutions,especially at pH=8.The optimal electrolyte compositions(mass fraction)are 6% HEDP,0.3% TTA and 3% TAC at pH=8.The main factor affecting the thickness of the oxide layer formed during ECMP process is the applied potential.The soft layer formation is a major mechanism for electrochemical enhanced mechanical abrasion.The surface topography evolution before and after electrochemical polishing(ECP)illustrates the mechanism of mechanical abrasion accelerating electrochemical dissolution,that is,the residual stress caused by the mechanical wear enhances the electrochemical dissolution rate.This understanding is beneficial for optimization of ECMP processes.展开更多
Bio-oil is a new liquid fuel produced by fast pyrolysis,which is a promising technology to convert bio-mass into liquid. Pyrolytic lignin extracted from bio-oil,a fine powder,contributes to the instability of bio-oil....Bio-oil is a new liquid fuel produced by fast pyrolysis,which is a promising technology to convert bio-mass into liquid. Pyrolytic lignin extracted from bio-oil,a fine powder,contributes to the instability of bio-oil. The paper presents the structural features of three kinds of pyrolytic lignin extracted from bio-oil with different methods(WIF,HMM,and LMM) . The pyrolytic lignin samples are characterized by Fourier transform infrared spectrometer(FTIR) and X-ray photoelectron spectroscopy(XPS) . FTIR data indicate that the three pyrolytic lignin samples have similar functional groups,while the absorption intensity is different,and show characteristic vibra-tions of typical lignocellulosic material groups O H(3340-3380 cm-1) ,C H(2912-2929 cm-1) and C O(1652-1725 cm-1) . Comparison in the region(3340-3380 cm-1) indicates that WIF has more O H stretch groups than HMM and LMM. The carbon spectra are fitted to four peaks:C1,C C or C H,BE 283.5 eV;C2,C OR or C OH,BE 284.5-285.8 eV;C3,C O or HO C OR,BE 286.10-287.10 eV;C4,O C O,BE 287.5-287.7 eV. The absence of C1,C C or C H indicates the dominant polymerization structure of aro-matic carbon in pyrolytic lignin samples. For HMM and WIF,C2a and C2b can not be separated,so there is no free hydroxyl group in the samples. The oxygen peaks are also fitted to four peaks:O1,OH,BE = 530.3 eV;O2,RC O,BE 531.45-531.72 eV;O3,O C O,BE = 532.73-533.74 eV;O4,H2O,BE 535 eV. The absence of O1 and O4 indicates that little hydroxyl groups and adsorbed water are present in the samples.展开更多
Various Au/GO catalysts were prepared by depositing Au nanoparticles on thermally- and chemically-treated graphite oxide （GO） supports using a sol-immobilization method. The surface chemistry and structure of GO sup...Various Au/GO catalysts were prepared by depositing Au nanoparticles on thermally- and chemically-treated graphite oxide （GO） supports using a sol-immobilization method. The surface chemistry and structure of GO supports were characterized by a series of analytical techniques including X-ray photoelectron spectroscopy, temperature-programmed desorption and Raman spectroscopy. The results show that thermal and chemical treatments have large influence on the presence of surface oxygenated groups and the crystalline structure of GO supports. A strong support effect was observed on the catalytic activity of Au/GO catalysts in the liquid phase aerobic oxidation of benzyl alcohol. Compared to the amount and the type of surface oxygen functional groups, the ordered structure of GO supports may play a more important role in determining the catalytic performance of Au/GO catalysts.展开更多
Optical microscopy, and scanning electron microscopy in conjunction with energy dispersed X-ray spectrometry （SEM-EDX）, have been used to study the minerals and the concentrations of 12 trace elements in the No.14 c...Optical microscopy, and scanning electron microscopy in conjunction with energy dispersed X-ray spectrometry （SEM-EDX）, have been used to study the minerals and the concentrations of 12 trace elements in the No.14 coal from the Huolinhe mine, Inner Mongolia China. The distribution, affinity and removability of the trace elements were studied by float-sink experiments and petrological methods. A high mineral content, dominated by clay minerals, was found in the No.14 coal from the Huolinhe mine. The concentrations of As, Sb and Hg are relatively high compared to the average values for Chinese coals. As, Cr, Hg, Li, Mn, Pb are mainly associated with the minerals while Cd, Co, Ni, Sb, and Se are evenly distributed between the minerals and the organic matter. Be and Ba are mainly distributed in the minerals with a minor proportion in the organic matter. Most elements have a low organic affinity, although Sb, Se, Co, Cd, Ni are closely integrated with the organic matter. High theoretical removabilities are indicated for most trace elements. So it may be possible to lower the concentrations of trace elements during coal preparation.展开更多
The geometric and electronic structures of several possible adsorption configurations of the pyrazine(C4H4N2)molecule covalently attached to Si(100)surface,which is of vital importance in fabricating functional nano-d...The geometric and electronic structures of several possible adsorption configurations of the pyrazine(C4H4N2)molecule covalently attached to Si(100)surface,which is of vital importance in fabricating functional nano-devices,have been investigated using X-ray spectroscopies.The Carbon K-shell(1s)X-ray photoelectron spectroscopy(XPS)and near-edge X-ray absorption fine structure(NEXAFS)spectroscopy of predicted adsorbed structures have been simulated by density functional theory with cluster model calculations.Both XPS and NEXAFS spectra demonstrate the structural dependence on different adsorption configurations.In contrast to the XPS spectra,it is found that the NEXAFS spectra exhibiting conspicuous dependence on the structures of all the studied pyrazine/Si(100)systems can be well utilized for structural identification.In addition,according to the classification of carbon atoms,the spectral components of carbon atoms in different chemical environments have been investigated in the NEXAFS spectra as well.展开更多
The dissolution mechanism of hemimorphite in NH3-（NH4）2SO4-H2O system at 298.15 K was investigated by X-ray powder diffraction （XRD）, scanning electron microscopy （SEM）, Fourier transform infrared spectroscopy ...The dissolution mechanism of hemimorphite in NH3-（NH4）2SO4-H2O system at 298.15 K was investigated by X-ray powder diffraction （XRD）, scanning electron microscopy （SEM）, Fourier transform infrared spectroscopy （FTIR） and X-ray photoelectron spectroscopy （XPS） analysis. The results show that hemimorphite is soluble in NH3-（NH4）2SO4-H2O system and its residue exists in the form of an amorphous SiO2 layer on the hemimorphite surface. The XPS data also indicate that the Si 2p3/2 and O ls spectra of the hemimorphite are broadened and shift to higher binding energies and their binding energies are closer to silica with an increase of total ammonia and time. Solubility of hemimorphite in NH3-（NH4）2SO4-H2O system was measured by means of isothermal solution method at 298.15 K based on the study of the dissolution mechanism of hemimorphite. The results show that the solubility of zinc in solution increases firstly and then decreases with the increase of cr（NH3） （total ammonia concentration） at different NH3/NH4^＋ ratios. The solubility of silicon in solution decreases from 0.0334 mol/kg in ct（NH3）-4.1245 mol/kg NH3-（NH4）2SO4-H2O solution to 0.0046 mol/kg in cT（NH3）=7.6035 mol/kg NH3-（NH4）2SO4-H2O solution.展开更多
文摘HAXPES （hard X-ray photoelectron spectroscopy） is a powerful emerging instrument in surface analysis. It extended the photoelectron energy range up to 15,000 eV and opened the possibility to study much thicker films, buried layers and bulk electronic properties. In order to study these features, data for the electron IMFP （inelastic mean free path） at these energies is needed. To date, only calculated IMFP are available at energies above 5,000 eV and therefore experimental validation of these calculations are essential. In this paper, a new approach for using the HAXPES spectra is presented. This approach, treats the attenuated part of the electron spectrum as a whole to calculating the average electron energy loss. This average electron energy loss is the result of inelastic collisions in the material and hence, carry with it information about the electron transport poses. Carbon layers with thicknesses between 20 and 75 nanometer deposited over copper substrate were used to test this approach at the Spanish beam-line （Spline） in the ESRF （European synchrotron radiation facility）. The measured results showed good agreement with the predictions of the multiple inelastic scattering theory. In addition, an algorithm for the experimental evaluation of electron IMFP, using the measured energy loss, is proposed.
文摘Nd2O3 doped BaTiO3ceramics（the additive content was respectively 0.001, 0.002, 0.003, 0.005, 0.01 molar ratio）were prepared by Sol-Gel method to study their dielectric characteristics and electric conductivities through X-ray photoelectron spectrum （XPS）. The results showed that the dielectric characteristics of Nd2O3 doped BaTiO3 ceramics were improved by doping. When Nd2O3 content was 0.003 mol, the results were even better, the dielectric constant was increased, the dielectric loss was decreased, the Curie-temperature （Tc） was 110 ℃, and the frequency characteristic was also good. The resistivity of Nd2O3 doped BaTiO3 ceramics was lower than that of pure BaTiO3 ceramics, when Nd2O3 content was 0.001 mol,the resistivity was （2.364×）108 Ω·m, the smallest. The grain resistance of Nd2O3 doped BaTiO3 ceramics exhibited NTC effect, but the grain boundary resistance showed PTC effect, and the grain boundary resistance was larger than that of the grain resistance, so the PTC effect originated from the grain boundary. The analysis of the element binding energy through X-ray photoelectron spectrum were indicated that the quantivalence of Ba2+and Ti4+in Nd2O3 doped BaTiO3 ceramics was variable, and resulted in the improvement of the conductibility of BaTiO3 ceramics.
基金Supported by the National Natural Science Foundation of China(51090384)
文摘Antibacterial activity of boron-doped TiO2(B/TiO2) nano-materials under visible light irradiation and in the dark was investigated. A simple sol-gel method was used to synthesize TiO2 nano-materials. X-ray diffraction pattern of B/TiO2 nano-materials represents the diffraction peaks relating to the crystal planes of TiO2(anatase and rutile). X-ray photoelectron spectroscopy result shows that part of boron ions incorporates into TiO2 lattice to form a possible chemical environment like Ti O B and the rest exist in the form of B2O3. The study on antibacterial effect of B/TiO2 nano-materials on fungal Candida albicans(ATCC10231), Gram-negative Escherichia coli(ATCC25922) and Gram-positive Staphylococcus aureus(ATCC6538) shows that the antibacterial action is more significant on Candida albicans than on Escherichia coli and Staphylococcus aureus. Under visible light irradiation, the antibacterial activity is superior to that in the dark.
基金Project(51374079)supported by the National Natural Science Foundation of ChinaProject(KKSY201521031)supported by Talent Cultivation Foundation of Kunming University of Science and Technology,ChinaProject(2015Y067)supported by Foundation of Yunnan Educational Committee,China
文摘The effect of dolomite with different particle size fractions on hematite flotation was studied using sodium oleate as collector at p H of about 9. The effect mechanism of dolomite on hematite flotation was investigated by means of solution chemistry, ultraviolet spectrophotometry(UV), inductively coupled plasma atomic emission spectrometry(ICP-AES) and X-ray photoelectron spectroscopy(XPS). It is observed that dolomite with different size fractions has depressing effect on hematite flotation using sodium oleate as collector, and dolomite could be the "mineral depressant" of hematite using sodium oleate as collector. The reasons for that are concerned with sodium oleate consumption and the adsorption onto hematite of dissolved species of dolomite.
文摘Infrared(IR)absorption spectroscopy has been widely used for dynamic characterization of catalysts and mechanism of catalytic reactions.However,due to the strong infrared absorption of heterogeneous catalysts(mainly oxides,or supported metal and metal oxides,etc.)below 1200 cm^(-1),and the intensity of regular infrared light source rapidly decays at low-wavenumber range,most in-situ infrared spectroscopy studies are limited to the detection of surface adsorbates in the range of 4000-900 cm^(-1).The change of catalytically active component itself(M-O,M-M bond,etc.,1200-50 cm^(-1))during the reaction is hard to be tracked under reaction conditions by in-situ IR.In this work,a home-made in-situ IR reactor was designed and a sample preparing method was developed.With such progresses,the changes of reactants,products,surface adsorbates,and catalysts themselves can be measured under the same reaction conditions with a spectral range of 4000-400 cm^(-1),providing a new opportunity for in-situ characterization of heterogeneous catalysis.CO oxidation on Pd/SiO_(2) and Cu/SiO_(2) catalysts were taken as examples,since both the two catalytic systems were extensively used commercially,and moreover reduction and oxidation of palladium and copper occur during the examined reaction conditions.The characteristic bands of Pd^(2+)-O(670,608 cm^(-1)),Cu^(+)-O(635 cm^(-1))and Cu^(2+)-O(595,535 cm^(-1))were observed by IR,and the changes during CO oxidation reaction were successfully monitored by IR.The oxidation/reduction of palladium and copper were also confirmed by ex-situ XPS.Moreover,Pd^(0) in Pd/SiO_(2) and Cu^(+)in Cu/SiO_(2) were found as the thermal dynamically stable phases under the examined conditions for CO oxidation.
文摘Carbonaceous catalysts are potential alternatives to metal catalysts. Graphene has been paid much attention for its high surface area and light weight. Here, hydrogenated graphene has been prepared by a simple gamma ray irradiation of graphene oxide aqueous suspension at room temperature. Transmission electron microscopic, element analysis, X-ray photoelectron spectroscopy, and UV-Vis spectrophotometer studies verified the hydrogenation of graphene. The as-prepared hydrogenated graphene can be used as a metal-free carbonaceous catalyst for the Fenton-like degradation of organic dye in water.
基金Project(2010JM7010)supported by the Natural Science Foundation of Shaanxi Province,ChinaProject supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,Ministry of Education,ChinaProject supported by the Technology Foundation for Selected Overseas Chinese Scholars,Department of Human Resources and Social Security of Shaanxi Province,China
文摘Pickling sludge generated during the neutralization of pickling wastewater with calcium hydroxide in stainless steel pickling process was characterized using X-ray fluorescence spectrometry, X-ray diffractometry, scanning electron microscopy, thermogravimetry and differential scanning calorimetry, etc. The major compositions of pickling sludge are CaF2, CaSO4, Me（OH）, （M： Fe, Cr, Ni）, and the content of CaF2 is high in the sludge. The melting point of pickling sludge is about 1350℃ and the viscosity is about 0.14 Pa.s at 1450 ℃, which are comparatively lower than those of normal refining slag. After heat treatment, the contents of sulfur and fluorine in the pickling sludge were reduced, confirming the thermal decomposition of sulfate in the sludge. Fluorine in the sludge is reduced by the gaseous SiF4 and A1F3 generated through the reactions of CaF2 with SiO2 and Al2O3. The preliminary results from the reduction test indicate that the sulfur content in the steel is not affected by the presence of sulfur in the sludge. The recovery of nickel is about 40%, and the chromium content changes marginally due to the protective atmosphere under the reduction condition of chromic oxide. The pickling sludge is a potential auxiliary material for the production of stainless steel.
基金Supported by the Fundamental Research Funds for the Central Universities(2017XKQY066)
文摘The aim of this paper is to analyze the change in the active structure of lignite during the process of lowtemperature oxidation by constructing a molecular structure model for lignite. Using quantum computation combined with experimental results of proximate analysis, ultimate analysis, Fourier transform infrared spectroscopy(FTIR) and X-ray photoelectron spectroscopy(XPS), a structural model for the large molecular structure was constructed. By analyzing the bond lengths in the model molecule, the evolution law for the active structure of lignite was predicted for the process of low-temperature oxidation. In low-temperature oxidation,alkanes and hydroxyls are the primary active structures observed in lignite, though ether may also react. These active functional groups react with oxygen to release heat, thereby speeding up the reaction between coal and oxygen. Finally, the content of various functional groups in the process of lignite low-temperature oxidation was analyzed by infrared analysis, and the accuracy of the model was verified.
基金Supported by the Hong Kong Research Grant Council(605009)the Hong Kong Innovation Technology Fund(ITS/108/09FP)the Environment and Conservation Fund(ECWW11EG02)
文摘The silk sericin is the main residue in silk production and it is found to be a low cost and efficient bio-sorbent. In this study, sericin was characterized with various techniques including SEM （scanning electron micro- scope）, XRD, N2 physisorption, FTIR （Fourier transformed infrared spectroscopy） and XPS （X-ray photoelectron spectroscopy）. The nitrogen content of sericin was ca. 8.5 mmol.g-1 according to elemental analysis. Dye adsorption by sericin biosorbent was investigated with the acid yellow （AY）, methylene blue （MB） and copper （II） phthalocyanine-3,4＇4＂4＇＂-tetrasulfonic acid （CuPc） dyes from water. Sericin displayed large capacity for AY andCuPc adsorption with adsorption capacities of respectively 3.1 and 0.35 mmol.g-1, but it did not adsorbed methyl- ene blue dye. This selectivity is due to the basicity of amide groups in seriein biosorbents.
基金ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China （No.20773113）, the Solar Energy Project of Chinese Academy of Sciences, the Ministry of Education program for PCSIRT （No.IRT0756）, and the Max Planck Gesellschaft of Chinese Academy of Sciences partner group.
文摘We developed a novel approach for the preparation of N-doped TiO2 photocatalysts by calcining ammonium titanium oxalate at different temperatures. The structures of N-TiO2 were characterized by powder X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, N2 adsorption-desorption isotherms, X-ray photoelectron spectroscopy, diffuse reflectance UV-Vis spectroscopy, and scanning electron microscope. The N-doped TiO2 photocatalysts calcined below 700 ℃ are the pure anatase phase but that calcined at 700 ℃ is a mixture of anatase and rutile phases. The doped N locates at the interstitial site of TiO2 which leads to the narrowing of bad gap of pure anatase N-TiO2. Among all photocatalysts, N-TiO2 photocatalysts calcined at 600 and 400 ℃ exhibit the best performance in the photodegradation of methyl orange under the UV light and all-wavelength light illuminations, respectively; however, because of the perfect crystallinity and the existence of anatase-rutile phase junctions, N-TiO2 photocatalyst calcined at 700 ℃ exhibits the highest specific photodegradation rate, i.e., the highest quantum yield, under both the UV light and all-wavelength light illuminations.
基金Supported by the National Natural Science Foundation of China （20901063） the Natural Science Foundation of Hubei Province （2011CDB221）
文摘In this manuscript, a series of catalyst SG n-[VVO2-PAMAM-MSA] (SG silica gel, PAMAM polyamidoamine, MSA 5-methyl salicylaldehyde, n=0, 1, 2, 3) was prepared and their structures were fully characterized by Fourier transform-infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and inductive coupled plasma emission spectrometer (ICP) etc. XPS revealed that the metal V and SG n-PAMAM-MSA combined more closely after the formation of Schiff base derivatives. Their catalytic activities for oxidation of dibenzothiophene were evaluated using tert-butyl hydroperoxide as oxidant. The results showed that the catalyst SG 2.0-[VVO2-PAMAM-MSA] presented good catalytic activity and recycling time. Meanwhile, the optimal condition for the catalytic oxidation of SG 2.0-[VVO2-PAMAM-MSA] was also investigated, which showed that when the oxidation temperature was 90 °C, time was 60 min, the O/S was 3:1, and the mass content of catalyst was 1%, the rate of desulfurization could reach 85.2%. Moreover, the catalyst can be recycled several times without significant decline in catalytic activity.
基金Supported by the Innovative Research Team Program by the Ministry of Education of China(IRT13070)the Nature Science Foundation of Jiangsu Province(BK2012423,BK20130925)the Opening Project of State Key Laboratory of Materials-Oriented Chemical Engineering of China(KL13-02)
文摘Photocatalytic degradation is one of the most promising remediation technologies in terms of advanced oxidation processes(AOPs) for water treatment. In this study, novel graphitic carbon nitride/titanium dioxide(gC3N4/Ti O2) composites were synthesized by a facile sonication method. The physicochemical properties of the photocatalyst with different mass ratios of g-C3N4 to Ti O2 were investigated by X-ray diffraction(XRD), scanning electron microscope(SEM), transmission electron microscopy(TEM), N2 sorption, Fourier transform infrared spectroscopy(FT-IR), X-ray photoelectron spectroscopy(XPS), and UV–vis DRS. The photocatalytic performances were evaluated by degradation of methylene blue. It was found that g-C3N4/Ti O2 with a mass ratio of 1.5:1 exhibited the best degradation performance. Under UV, the degradation rate of g-C3N4/Ti O2 was 6.92 and 2.65 times higher than g-C3N4 and Ti O2, respectively. While under visible light, the enhancement factors became 9.27(to g-C3N4) and 7.03(to Ti O2). The improved photocatalytic activity was ascribed to the interfacial charge transfer between g-C3N4 and Ti O2. This work suggests that hybridization can produce promising solar materials for environmental remediation.
基金Project(50975058)supported by the National Science Foundation of China
文摘The optimization of electrolytes and the material removal mechanisms for Cu electrochemical mechanical planarization(ECMP)at different pH values including 5-methyl-1H-benzotriazole(TTA),hydroxyethylidenediphosphoric acid(HEDP),and tribasic ammonium citrate(TAC)were investigated by electrochemical techniques,X-ray photoelectron spectrometer(XPS)analysis,nano-scratch tests,AFM measurements,and polishing of Cu-coated blanket wafers.The experimental results show that the planarization efficiency and the surface quality after ECMP obtained in alkali-based solutions are superior to that in acidic-based solutions,especially at pH=8.The optimal electrolyte compositions(mass fraction)are 6% HEDP,0.3% TTA and 3% TAC at pH=8.The main factor affecting the thickness of the oxide layer formed during ECMP process is the applied potential.The soft layer formation is a major mechanism for electrochemical enhanced mechanical abrasion.The surface topography evolution before and after electrochemical polishing(ECP)illustrates the mechanism of mechanical abrasion accelerating electrochemical dissolution,that is,the residual stress caused by the mechanical wear enhances the electrochemical dissolution rate.This understanding is beneficial for optimization of ECMP processes.
基金Supported by State Key Development Program for Basic Research of China(2007CB210208)National Science and Technology Major Project of China(2008ZX07101)China Scholarship Council(CSC),Natural Science and Engineering Research Council of Canada(NSERC),BIOCAP,and Canadian Funding for Innovations(CFI)
文摘Bio-oil is a new liquid fuel produced by fast pyrolysis,which is a promising technology to convert bio-mass into liquid. Pyrolytic lignin extracted from bio-oil,a fine powder,contributes to the instability of bio-oil. The paper presents the structural features of three kinds of pyrolytic lignin extracted from bio-oil with different methods(WIF,HMM,and LMM) . The pyrolytic lignin samples are characterized by Fourier transform infrared spectrometer(FTIR) and X-ray photoelectron spectroscopy(XPS) . FTIR data indicate that the three pyrolytic lignin samples have similar functional groups,while the absorption intensity is different,and show characteristic vibra-tions of typical lignocellulosic material groups O H(3340-3380 cm-1) ,C H(2912-2929 cm-1) and C O(1652-1725 cm-1) . Comparison in the region(3340-3380 cm-1) indicates that WIF has more O H stretch groups than HMM and LMM. The carbon spectra are fitted to four peaks:C1,C C or C H,BE 283.5 eV;C2,C OR or C OH,BE 284.5-285.8 eV;C3,C O or HO C OR,BE 286.10-287.10 eV;C4,O C O,BE 287.5-287.7 eV. The absence of C1,C C or C H indicates the dominant polymerization structure of aro-matic carbon in pyrolytic lignin samples. For HMM and WIF,C2a and C2b can not be separated,so there is no free hydroxyl group in the samples. The oxygen peaks are also fitted to four peaks:O1,OH,BE = 530.3 eV;O2,RC O,BE 531.45-531.72 eV;O3,O C O,BE = 532.73-533.74 eV;O4,H2O,BE 535 eV. The absence of O1 and O4 indicates that little hydroxyl groups and adsorbed water are present in the samples.
基金This work was supported by the Natural Science Foundation of Anhui Province （No.11040606M39） and the Fundamental Research Funds for the Central Universities.
文摘Various Au/GO catalysts were prepared by depositing Au nanoparticles on thermally- and chemically-treated graphite oxide （GO） supports using a sol-immobilization method. The surface chemistry and structure of GO supports were characterized by a series of analytical techniques including X-ray photoelectron spectroscopy, temperature-programmed desorption and Raman spectroscopy. The results show that thermal and chemical treatments have large influence on the presence of surface oxygenated groups and the crystalline structure of GO supports. A strong support effect was observed on the catalytic activity of Au/GO catalysts in the liquid phase aerobic oxidation of benzyl alcohol. Compared to the amount and the type of surface oxygen functional groups, the ordered structure of GO supports may play a more important role in determining the catalytic performance of Au/GO catalysts.
文摘Optical microscopy, and scanning electron microscopy in conjunction with energy dispersed X-ray spectrometry （SEM-EDX）, have been used to study the minerals and the concentrations of 12 trace elements in the No.14 coal from the Huolinhe mine, Inner Mongolia China. The distribution, affinity and removability of the trace elements were studied by float-sink experiments and petrological methods. A high mineral content, dominated by clay minerals, was found in the No.14 coal from the Huolinhe mine. The concentrations of As, Sb and Hg are relatively high compared to the average values for Chinese coals. As, Cr, Hg, Li, Mn, Pb are mainly associated with the minerals while Cd, Co, Ni, Sb, and Se are evenly distributed between the minerals and the organic matter. Be and Ba are mainly distributed in the minerals with a minor proportion in the organic matter. Most elements have a low organic affinity, although Sb, Se, Co, Cd, Ni are closely integrated with the organic matter. High theoretical removabilities are indicated for most trace elements. So it may be possible to lower the concentrations of trace elements during coal preparation.
基金the National Natural Science Foundation of China(No.11874242,No.11804196,No.11804197)support provided by China Scholarship Council(CSC)for Yong Ma to Royal Institute of Technology(KTH)is acknowledgedsupport of the Taishan Scholar Project of Shandong Province。
文摘The geometric and electronic structures of several possible adsorption configurations of the pyrazine(C4H4N2)molecule covalently attached to Si(100)surface,which is of vital importance in fabricating functional nano-devices,have been investigated using X-ray spectroscopies.The Carbon K-shell(1s)X-ray photoelectron spectroscopy(XPS)and near-edge X-ray absorption fine structure(NEXAFS)spectroscopy of predicted adsorbed structures have been simulated by density functional theory with cluster model calculations.Both XPS and NEXAFS spectra demonstrate the structural dependence on different adsorption configurations.In contrast to the XPS spectra,it is found that the NEXAFS spectra exhibiting conspicuous dependence on the structures of all the studied pyrazine/Si(100)systems can be well utilized for structural identification.In addition,according to the classification of carbon atoms,the spectral components of carbon atoms in different chemical environments have been investigated in the NEXAFS spectra as well.
基金Projects(511340071) supported by the National Natural Science Foundation of China
文摘The dissolution mechanism of hemimorphite in NH3-（NH4）2SO4-H2O system at 298.15 K was investigated by X-ray powder diffraction （XRD）, scanning electron microscopy （SEM）, Fourier transform infrared spectroscopy （FTIR） and X-ray photoelectron spectroscopy （XPS） analysis. The results show that hemimorphite is soluble in NH3-（NH4）2SO4-H2O system and its residue exists in the form of an amorphous SiO2 layer on the hemimorphite surface. The XPS data also indicate that the Si 2p3/2 and O ls spectra of the hemimorphite are broadened and shift to higher binding energies and their binding energies are closer to silica with an increase of total ammonia and time. Solubility of hemimorphite in NH3-（NH4）2SO4-H2O system was measured by means of isothermal solution method at 298.15 K based on the study of the dissolution mechanism of hemimorphite. The results show that the solubility of zinc in solution increases firstly and then decreases with the increase of cr（NH3） （total ammonia concentration） at different NH3/NH4^＋ ratios. The solubility of silicon in solution decreases from 0.0334 mol/kg in ct（NH3）-4.1245 mol/kg NH3-（NH4）2SO4-H2O solution to 0.0046 mol/kg in cT（NH3）=7.6035 mol/kg NH3-（NH4）2SO4-H2O solution.
