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1.
Yin Liu Zhiguo Yi Jian‐jun Li Tai Qiu Fan‐fei Min Ming‐xu Zhang 《Journal of the American Ceramic Society》2013,96(1):151-156
Nanocrystalline Ni1?xZnxFe2O4 (0 ≤ x ≤ 1.0) powder with grain size of 30 nm was prepared using the spraying‐coprecipitation method. The obtained nanocrystalline Ni1?xZnxFe2O4 powder was sintered using conventional and microwave sintering techniques. The results show that the microstructure and magnetic properties of the sintered samples are obviously improved by microwave sintering of nanocrystalline Ni1?xZnxFe2O4 ferrite powder. The initial permeability of Ni1?xZnxFe2O4 ferrite increases with the increase in zinc concentration, although its resonance frequencies shift from high frequency to low frequency. The maximum initial permeability for microwave‐sintered Ni0.4Zn0.6Fe2O4 ceramic obtained at the temperature of 1170°C for 30 min reaches up to 360.9, and its resonance frequency is ~10 MHz. It may be attributed to the nanocrystalline Ni1?xZnxFe2O4 raw powder as well as the microwave sintering process, which results in a synergistic effect on improvement of the microstructure and magnetic properties. 相似文献
2.
Arunachalam Sendilkumar Peram Delli Babu Muthuvel Manivel Raja Varimalla Raghavendra Reddy Ajay Gupta Sanyadanam Srinath 《Journal of the American Ceramic Society》2013,96(9):2973-2978
Crystal structure and cation distribution of nanocrystalline SrFe1?xTixO3?δ (0 ≤ x ≤ 0.3) synthesized by combined high‐energy ball milling and solid‐state reactions are investigated using Neutron powder diffraction and Mössbauer spectroscopy. Ti doping stabilizes the single phase tetragonal structure with I4/mmm space group up to x = 0.3. The neutron and Mössbauer data confirm that Fe exists in three different sites both crystallographically as well as magnetically in all the four compositions. The cation distribution at various sites is established through Rietveld refinement. 相似文献
3.
The structure, electrical conduction, thermal expansion and electrochemical properties of the La0.6Sr0.4Co0.2Fe0.8O3–δ + La2NiO4+δ (LSCF‐LNO) composite cathodes were investigated with regard to the volume fraction of the LNO composition. No chemical reaction product between the two constituent phases was found for the composite cathodes sintered at 1,400 °C for 10 h within the sensitivity of the XRD. Compared to the performance of the LSCF cathode, the LNO composition in the composite cathode plays a role in deteriorating both electrical conductivity and electrochemical properties, however, improving the thermal expansion properties. The trade‐off between electrical conducting and thermal expansion classifies the composite cathode containing 30 volume percent (vol.%) LNO as the optimum composition. For characterizing cathode performance in a single cell, a slurry spin coating technique was employed to prepare a porous cathode layer as well as a YSZ/Ce0.8Sm0.2O3–δ (SDC) electrolyte. The optimum conditions for fabricating the YSZ/SDC electrolyte were investigated. The resulting single cell with 70 vol.% LSCF‐30 vol.%LNO (LSCF‐LNO30) cathode shows a power density of 497 mW cm–2 at 800 °C, which is lower than that of the cell with a LSCF cathode, but still within the limits acceptable for practical applications. 相似文献
4.
Jonathan M. Polfus Wen Xing Marit Riktor Martin F. Sunding Paul Inge Dahl Sidsel M. Hanetho Tommy Mokkelbost Yngve Larring Marie‐Laure Fontaine Rune Bredesen 《Journal of the American Ceramic Society》2016,99(3):1071-1078
Dense symmetric membranes of CaTi0.85?xFe0.15MnxO3?δ (x = 0.1, 0.15, 0.25, 0.4) are investigated in order to determine the optimal Mn dopant content with respect to highest O2 flux. O2 permeation measurements are performed as function of temperature between 700°C–1000°C and as function of the feed side ranging between 0.01 and 1 bar. X‐ray photoelectron spectroscopy is utilized to elucidate the charge state of Mn, and synchrotron radiation X‐ray powder diffraction (SR‐XPD) is employed to investigate the structure symmetry and cell volume of the perovskite phase at temperatures up to 800°C. The highest O2 permeability is found for x = 0.25 over the whole temperature and ranges, followed by x = 0.4 above 850°C. The O2 permeability for x = 0.25 reaches 0.01 mL(STP) min?1 cm?1 at 925°C with 0.21 bar feed side and Ar sweep gas. X‐ray photoelectron spectroscopy indicates that the charge state of Mn changes from approx. +3 to +4 when x > 0.1, which implies that Mn mainly improves electronic conductivity for x > 0.1. The cell volume is found to decrease linearly with Mn content, which coincides with an increase in the activation energy of O2 permeability. These results are consistent with the interpretation of the temperature and dependency of O2 permeation. The sintering behavior and thermal expansion properties are investigated by dilatometry, which show improved sinterability with increasing Mn content and that the thermal expansion coefficient decreases from 12.4 to 11.9 × 10?6 K?1 for x = 0 and x = 0.25, respectively. 相似文献
5.
6.
Comparative Study of Silver Nanoparticles Coated and Uncoated NiO–Fe2O3–CaO–SiO2–P2O5 Ferromagnetic Bioactive Ceramics
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Vikas Anand Kanwarjit Singh Kulwinder Kaur Harpreet Kaur Gaurav Bhatia Sukhdev Singh Daljit Singh Arora 《Journal of the American Ceramic Society》2016,99(11):3632-3638
Bioactive ferromagnetic ceramics of system xNiO–(3?x)Fe2O3–52CaO–30SiO2–15P2O5, (x = 0, 3 mol%) have been prepared in the laboratory using sol–gel technique. Silver nanoparticles coating has been undertaken on the surface of synthesized samples. Comparative study of silver nanoparticles coated and uncoated samples has been undertaken with the help of transmission electron microscopy, X‐ray diffraction (XRD), degradation, drug delivery, hemolysis, antimicrobial, and cell culture studies. XRD patterns indicate the growth of hydroxyl apatite layer on the surface of coated as well as uncoated samples. Ferromagnetic properties of samples have been investigated with the help of vibrating sample magnetometer technique. Samples have shown good response as drug carriers under normal conditions as well as under the influence of magnetic field. Drug release mechanism and mesoporus nature of samples have been investigated with the help of Brunauer–Emmett–Teller technique. Nonreactivity of samples (coated and uncoated) with red blood cells and white blood cells show nontoxic nature of the samples. Coated samples have shown better antimicrobial properties against six different microorganisms, including some resistive strain like methicillin‐resistant Staphylococcus aureus with minimum inhibitory concentration of 0.05 mg/ml as compared to uncoated samples. It has been observed that samples also provide a healthy environment for the growth of MG 63 cell lines. It has been noticed that presence of silver nanoparticles on the surface of samples improve degradation and antimicrobial properties. 相似文献
7.
The high‐temperature solid oxide electrolysis cell (SOEC) is one of the most promising devices for hydrogen mass production. To make SOEC suitable from an economical point of view, each component of the SOEC has to be optimized. At this level, the optimization of the oxygen electrode is of particular interest since it contributes to a large extent to the cell polarization resistance. The present paper is focused on an alternative oxygen electrode of Zr0.84Y0.16O2–δ‐Sr2Fe1.5Mo0.5O6–δ (YSZ‐SFM). YSZ‐SFM composite oxygen electrodes were fabricated by impregnating the YSZ matrix with SFM, and the ion‐impregnated YSZ‐SFM composite oxygen electrodes showed excellent performance. For a voltage of 1.2 V, the electrolysis current was 223 mA cm−2, 327 mA cm−2 and 310 mA cm−2 at 750 °C for the YSZ‐SFM10, YSZ‐SFM20, and YSZ‐SFM30 oxygen electrode, respectively. A hydrogen production rate as high as 11.46 NL h−1 has been achieved for the SOEC with the YSZ‐SFM20 electrode at 750 °C. The results demonstrate that YSZ‐SFM fabricated by impregnating the YSZ matrix with SFM is a promising composite electrode for the SOEC. 相似文献
8.
Acceptor‐doped BaTiO3 powders of formula: BaTi1?xHoxO3?x/2?δ/2: x = 0.0001, 0.001, 0.01, 0.03, and 0.07, were prepared by sol‐gel synthesis, fired at 800°C–1500°C and either quenched or slow‐cooled to room temperature. Electrical properties of ceramics depended on firing conditions, Ho content, and cooling rate. Pellets of all x values fired at 800°C–1000°C were insulating and, from the presence of OH bands in the IR spectra, charge balance appeared to involve co‐doping of Ho3+ and H+ ions without necessity for oxygen vacancy creation. At higher firing temperatures, OH bands were absent. Pellets fired at 1400°C in air and slow cooled were insulating for both low x (0.0001) and high x (0.07) but at intermediate x (0.001 and 0.01) passed through a resistivity minimum of 20–30 Ω cm at room temperature, attributed to the presence of Ti3+ ions; it is suggested that, for these dilute Ho contents, each oxygen vacancy is charge compensated by one Ho3+ and one Ti3+ ion. At higher x, charge compensation is by Ho3+ ions and samples are insulating. A second, more general mechanism to generate Ti3+ ions, and a modest level of semiconductivity, involves reversible oxygen loss at high temperatures. 相似文献
9.
Structural elucidation and iron oxidation states in situ formed β‐Ca3(PO4)2/α‐Fe2O3 composites
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Ponnusamy Nandha Kumar Sandeep K. Mishra Sanjeevi Kannan 《Journal of the American Ceramic Society》2017,100(8):3746-3756
A detailed structural analysis on the in situ synthesized β‐Ca3(PO4)2/α‐Fe2O3 composites is demonstrated. Compositional ratios, the influence and occupancy of iron at the β‐Ca3(PO4)2 lattice, oxidation state of iron in the composites are derived from analytical techniques involving XRD, FT‐IR, Raman, refinement of the powder X‐ray diffraction and X‐ray photoelectron spectroscopy. Iron exists in the Fe3+ state throughout the investigated systems and favors its occupancy at the Ca2+(5) site of β‐Ca3(PO4)2 until critical limit, and thereafter crystallizes as α‐Fe2O3 at ambient conditions. Fe3+ occupancy at the β‐Ca3(PO4)2 lattice yields a Ca9Fe(PO4)7 structure that is isostructural with its counterpart. A strong rise in the soft ferromagnetic behavior of β‐Ca3(PO4)2/α‐Fe2O3 composites is obvious that depends on the content of α‐Fe2O3 in the composites. Overall, the diverse level of iron inclusions at the calcium phosphate system with a Ca/P ratio of 1.5 yields a structurally stable β‐Ca3(PO4)2/α‐Fe2O3 composites with assorted compositional ratios. 相似文献
10.
Ce0.8Y0.2O2–δ (YDC) was infiltrated into a BaCo0.7Fe0.2Nb0.1O3–δ (BCFN) cathode of intermediate temperature sold oxide full cells (IT‐SOFCs) in order to decrease its cathodic polarization resistance. BCFN and YDC infiltrated BCFN electrodes were fabricated on dense Ce0.8Gd0.2O2–δ (GDC) thin pellets to form symmetrical cells. The electrochemical impedance spectra of the symmetrical cells were investigated in this present study. Firstly, the thickness of BCFN electrodes was optimized, and controlled at 30 µm for further study. The effects of infiltrated YDC amount and firing temperature on electrode polarization resistance were studied. The symmetrical cells infiltrated with 30 μL YDC solution and fired at 900 °C exhibited the lowest electrode polarization resistance in all samples. It was suggested that infiltration of YDC resulted in more active sites and prolonged TPBs in electrodes, improving the surface oxygen exchange, and finally improved the electrode performance. 相似文献
11.
Structural and Piezoelectric Properties of (1−x)Pb(Zr1−yTiy)O3–xPb(Zn0.4Ni0.6)1/3Nb2/3O3 Ceramics Near Triple Point
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Joon Hur Jong‐Hyun Kim Tae‐Gon Lee In‐Tae Seo Dae‐Hyeon Kim Sahn Nahm Chong‐Yun Kang 《Journal of the American Ceramic Society》2015,98(9):2887-2893
The crystal structure and piezoelectric properties of (1?x)Pb(Zr1?yTiy)O3‐xPb(Zn0.4Ni0.6)1/3Nb2/3O3 [(1?x)PZ1?yTy‐xPZNN] ceramics were investigated. The 0.665PZ0.45T0.55‐0.335PZNN ceramic has the triple point composition, where the rhombohedral, pseudocubic, and tetragonal structures coexist. Maximum d33 and kp values of 770 pC/N and 0.69, respectively, were observed from this specimen; it also exhibited a large εT33/εo value of 3250. Although the maximum d33 value was obtained from the triple point composition specimen, its g33 and d33 × g33 values were relatively small because of its large εT33/εo value. However, the 0.665PZ0.46T0.54‐0.335PZNN ceramic, which has a rhombohedral structure, exhibited a large g33 value of 43 × 10?3 Vm/N and a d33 × g33 value of 27 000 × 10?15 m2/N. Therefore, this ceramic is a good candidate for multilayer actuators and piezoelectric energy harvesters. 相似文献
12.
Electrochemical Performance of PrBaCo2O5+δ and Sm0.5Sr0.5CoO3−δ Infiltrated Ce0.9Gd0.1O1.95 Cathodes
Cathodes with PrBaCo2O5+δ (PBC) and Sm0.5Sr0.5CoO3−δ (SSC) infiltrated on Ce0.9Gd0.1O1.95 (CGO) backbones are prepared using metal nitrates as precursors and ethanol as wetting agent. Electrochemical impedance spectra (EIS) are measured from cathode/CGO/cathode symmetrical cells in 400–650 °C under humidified air. The results indicate that interfacial area specific resistance (ASR) value decreases and then increases with infiltrate loading and minimum values occur at 50 wt.% loading (relative to sum of infiltrate and backbone) for both PBC and SSC infiltrates. ASR values of PBC infiltrated cathodes are lower than that of corresponding SSC infiltrated cathodes in general, and in particular ASR values as low as 1.36 × 10−2 and 2.27 × 10−2 Ω cm2 are obtained at 650 °C in air for 50 wt.% PBC and 50 wt.% SSC infiltrated cathodes, respectively. Conductivity values of CGO electrolyte increase with infiltrate loading and agree with the reported values when the loading reaches 50 wt.%. 相似文献
13.
Electrophoretic Deposition Kinetics and Characterization of Ni–La1.95Ca0.05Zr2O7−δ Particulate Thin Films
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Debasish Das Quazi Arif Islam Rajendra N. Basu 《Journal of the American Ceramic Society》2016,99(9):2937-2946
Suspensions of NiO–La1.95Ca0.05Zr2O7?δ (NiO–LCZ) composite material have been prepared in isopropanol medium using iodine and acetylacetone as dispersants. The effect of iodine concentration on suspension stability, electrical conductivity, and suspension pH are studied in detail to optimize the suspension chemistry. Electrophoretic deposition has been successfully conducted on conducting substrate (steel plate) to fabricate NiO–LCZ thin particulate films. Deposition kinetics have been studied in detail to optimize the process parameters. Good quality particulate films of such composite on steel plates are obtained at an applied voltage of 60 V for 3 min. The optimized suspension chemistry and process parameters thus obtained are then used to fabricate NiO–LCZ composite films onto nonconducting porous ceramic substrate by placing a conducting plate at the reverse side of the porous substrate. The deposited films along with the ceramic substrates are co‐fired at 1400°C for 6 h in reducing atmosphere (5% hydrogen in argon) to produce a good quality dense Ni–LCZ film of thickness ~40 μm. The hydrogen permeation flux of the developed cermet membrane has been measured and it reveals that Ni–LCZ could be used as a potential membrane for hydrogen separation at high temperature. 相似文献
14.
As anode‐support materials for solid oxide fuel cells, porous LaNbO4–NiO–Y2O3 stabilized ZrO2 (YSZ) composites (LNY), containing 0, 5, 10, 15, and 20 wt% of LaNbO4 and designated as 0LNO, 5LNO, 10LNO, 15LNO, and 20LNO, respectively, are prepared by tape casting and sintering. They are investigated for their microstructure and mechanical, electrical and thermal expansion properties. The porosity of as‐sintered LNY is around 30%, and that of reduced LNY cermets decreases from 47% for reduced 0LNO to 43% for reduced 20LNO. The fracture strength (σf) of LNY is higher than that of the reduced form; however, both of them are not rather sensitive to the amount of LaNbO4, depending on crack‐originating flaws in the specimens. The fracture toughness (KIC) of LNY increases with LaNbO4 content and is 1.87 MPa·m1/2 for 20LNO, which is more than 20% increase from that of 0LNO; however the KIC for reduced LNY is higher than that of LNY, and decreases with increasing LaNbO4 content due to the decreased amount of ductile metallic Ni phase. The conductivity of reduced LNY depends on Ni content and is higher than 289 S/cm at temperatures below 900°C. The coefficient of thermal expansion (CTE) of both LNY and reduced LNY is in the range between 12.4 and 11.4 × 10?6 K?1; which is closely matched with that of YSZ electrolyte. 相似文献
15.
Oxygen Nonstoichiometry and Thermodynamic Explanation of Large Oxygen‐Deficient Ruddlesden–Popper Oxides LaxSr3−xFe2O7−δ
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Yihan Ling Fang Wang Yusuke Okamoto Takashi Nakamura Koji Amezawa 《Journal of the American Ceramic Society》2016,99(11):3792-3801
The oxygen nonstoichiometry of large oxygen‐deficient Ruddlesden–Popper oxides LaxSr3?xFe2O7?δ (LSFO7‐x) (x = 0, 0.25, 0.5) was measured by the high‐temperature gravimetry and the coulometric titration. In the composition series, the P(O2) dependencies exhibited typical plateaus at δ = (2?[])/2. Meanwhile, La0.5Sr2.5Fe2O7?δ showed the smallest oxygen nonstoichiometry and was the most thermochemically stable compound against P(O2), temperature, and the La content. Based on the defect equilibrium model and the statistical thermodynamic calculation derived oxygen nonstoichiometric data, the substitution of La for Sr‐site can promote the forward reaction of oxygen incorporation, the backward reaction of the disproportionation of the charge carriers, and oxygen redistribution between the O1 and O3 sites, resulting in the reduction of oxygen‐deficient and the lower decomposition P(O2). The obtained thermodynamic quantities of the partial molar enthalpy of oxygen, , and the partial molar entropy of oxygen, , calculated from the statistical thermodynamic calculation are in good agreement with those using the Gibbs–Helmholtz equation. 相似文献
16.
Defective Y2O3−x–driven anomalous photocatalytic enhancement using Y2O3−x–TiO2−x nanorod composite composition spreads
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Neon Vicente Bacarro Rosell III Yen‐Ting Chen Kao‐Shuo Chang 《Journal of the American Ceramic Society》2017,100(12):5548-5560
Synergistic photocatalysis is reported, using the optimal amounts of oxygen vacancies of high‐k materials and nanoarchitecture maneuvering by employing a combinatorial sputtering approach. The highlights include (i) the successful fabrication of samples using combinatorial sputtering; (ii) a systematic investigation of the coupling effect between Y2O3?x and TiO2?x; (iii) elucidating charge carrier transport through current‐voltage (I‐V) and capacitance‐voltage (C‐V) characterizations; and (iv) providing an alternative application for high‐dielectric constant (high‐k) materials in photocatalysis. The simple yet effective composition spread technique rapidly determined that Sample 6 (4 at% Y2O3?x‐96 at% TiO2?x, TiO2?x‐rich on the Y2O3?x–TiO2?x nanorod composite composition spread) exhibited the highest photocatalytic efficiency (i.e., approximately 3.4 times and 1.4 times higher than that of P25 and pure TiO2?x nanorods, respectively). The predominant factor was determined to be electron migration along defective Y2O3?x nanorods to the sample surface. The extracted mobility was discovered to be an order of magnitude greater than that of pure TiO2?x. The photoelectrochemical stability and reusability were also demonstrated. 相似文献
17.
Larissa H. Oliveira Elaine C. Paris Waldir Avansi Miguel A. Ramirez Valmor R. Mastelaro Elson Longo José A. Varela 《Journal of the American Ceramic Society》2013,96(1):209-217
Ca1+xCu3 ? xTi4O12 powders were synthesized by a conventional solid‐state reaction. X‐ray diffraction (XRD) was performed to verify the formation of cubic CaCu3Ti4O12 (CCTO) and orthorhombic CaTiO3 (CTO) phases at long range. Rietveld refinements indicate that excess Ca atoms added to the Ca1 ? xCu3 ? xTi4O12 (x = 1.0) composition segregated in a CaTiO3 secondary phase suggesting that solubility limit of Ca atoms in the CaCu3Ti4O12 lattice was reached for this system. The FE‐SEM images show that the Ca1+xCu3 ? xTi4O12 (0 < x < 3) powders are composed of several agglomerated particles with irregular morphology. X‐ray absorption near‐edge structure spectroscopy (XANES) spectra indicated [TiO5Voz]‐[TiO6] complex clusters in the CaCu3Ti4O12 structure which can be associated with oxygen vacancies (Voz = Vox, Vo?, and Vo??) whereas in the CaTiO3 powder, this analysis indicated [TiO6]–[TiO6] complex clusters in the structure. Ultraviolet‐visible (UV–vis) spectra and photoluminescence (PL) measurements for the analyzed systems revealed structural defects such as oxygen vacancies, distortions, and/or strains in CaCu3Ti4O12 and CaTiO3 lattices, respectively. 相似文献
18.
Almost complete peritectic reaction in YBa2(Cu1−xFex)3O7−δ crystallization involving nanosized primary phase
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Gehai Du Haochen Li Hui Xiang Ghulam Hussain Yan Liu Xiangxiang Cui Pavel Diko Xin Yao Zhiqiang Zou 《Journal of the American Ceramic Society》2017,100(5):1804-1813
Study on peritectic reaction is a matter of significant importance in materials science, which generally involves in the solidification of most functional oxide materials, for example, the YBa2Cu3O7?δ (Y123) superconductor could be grown via a reaction of Y2BaCuO5 (Y211) + Liquid→Y123. Due to its crystallization characteristic, the growth of those materials does not entirely proceed, which severely impedes the development of industrialized process. Thus the realization of a complete peritectic reaction is an interesting issue for both theory and experiment. Here, we report an almost complete peritectic reaction occurring in the growth of YBa2(Cu1?xFex)3O7?δ crystals using modified melt‐growth. Our findings remarkably show that Y211 almost fully reacted with liquid to generate Y123, remaining approximately 1 vol%, evidently lower than that in the normal case. The nature of this unconventional phenomenon is clarified that the Fe‐doping elevates the nucleation barrier in the peritectic melting of Y123 and causes a massive homogeneous nucleation catastrophe, leading to nanosized and dispersive Y211 particles, which readily and almost fully dissolve in the subsequent peritectic solidification of Y123. Most importantly, the new conception derived from this work is promising for reviving other functional materials, which are disregarded due to their incomplete peritectic reactions. 相似文献
19.
Magdy W. Rophael Laila B. Khalil Mounir A. Malati 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1991,51(1):71-79
The superconductivity of the ceramic solid YBa2Cu3O7 ? δ, prepared by heating Y2O3, BaCO3 and CuO at 920°C for 22 h, was checked by the Meissner effect. Chemical analysis established the formula of the compound prepared. A thermostated aqueous suspension of the superconductor, treated with a solution of H2O2, produced oxygen, whose volume was measured at intervals in a gas burette. From the initial rates of the first-order reaction at different temperatures, the activation enthalpy and entropy were 16 kJ mol?1 and ?210 J K?1 mol?1 respectively. The rates of gas evolution were similar to those obtained when a MnO2 sample was used as a catalyst. Neither the superconductor nor its semiconductor phase photocatalysed the decomposition of KMnO4 solution. Evidence of the catalysed decomposition of N2H+5 by the superconductor is presented. 相似文献
20.
Jianguo Deng Yuxing Peng Chuanlan He Xingping Long Pei Li Albert S C Chan 《Polymer International》2003,52(7):1182-1187
Magnetic and conducting Fe3O4–polypyrrole nanoparticles with core‐shell structure were prepared in the presence of Fe3O4 magnetic fluid in aqueous solution containing sodium dodecylbenzenesulfonate (NaDS) as a surfactant and dopant. Both the conductivity and magnetization of the composites depend strongly on the Fe3O4 content and the doping degree. With increase of Fe3O4 content in the composite, the conductivity at room temperature decreases, but the saturated magnetization and coercive force increase. Transmission electron microscopy (TEM) images of Fe3O4 and Fe3O4–polypyrrole particles show almost spherical particles with diameters ranging from 20 to 30 and 30 to 40 nm, respectively. The thermal stability of Fe3O4–polypyrrole composites is higher than that of pure polypyrrole. Studies of IR, UV–visible and X‐ray photoelectron spectroscopy (XPS) spectra suggest that the increased thermal stability may be due to interactions between Fe3O4 particles and polypyrrole backbone. Copyright © 2003 Society of Chemical Industry 相似文献