The triplet lifetime of poly(phenyl vinyl ketone). A laser flash photolysis study

The photochemistry of poly(phenyl vinyl ketone) in solution has been examined over a temperature range using nanosecond laser flash photolysis techniques. Experiments were performed at low temperatures to eliminate the interference from biradical signals and allow for the separation in time of the behaviour of quencher-free and quencher-containing polymers. For the former the kinetics of triplet decay in toluene-d₈ lead to log $\text{(}\text{A}\text{s}{}^{\mathrm{?1}}\text{) = 9.90 ± 0.50}$ and E_a = (3.56 ± 0.30) kcal mol^?1 where A is the preexponential factor and E_a the activation energy. The extrapolated triplet lifetime at 20°C is 57 ns.     

Kinetics measurements on a stationary disk electrode in a uniformly rotating fluid (SDERF). II. The electron transfer reaction in the Fe(CN)4−6/Fe(CN)3−6-system

The operation of the SDERF-cell in the study of the electron transfer kinetics of the Fe(CN)^4?₆/Fe(CN)^3?₆-system in 1 M KCl and 1 M KNO₃-solutions at a stationary Pt-disk electrode is reported. The experimental current—overpotential curves are recorded by linear sweep voltammetry and analysed by two different methods using the theoretical relationship derived for a stationary disk electrode placed in a free rotating fluid. Both methods give the same value for the experimental rate constant k*. The effects of the temperature (0° to 40°C) and of the ratio of the rotor radius (r_r) to the electrode radius (r_e)(r_r/r_e = 0.50 to 0.81) have been studied. The activation energy for the redox process in 1 M KCl and 1 M KNO₃ are: E_a = 3.4 ± 0.6 kcal/mol and E_a = 3.7 ± 0.7 kcal/mol respectively, while the k*-values at 25°C are: k* = (5.67 ± 0.41) × 10^?3 cm.s^?1 and k* = (4.53 ± 0.29) × 10^?3 cm.s^?1 respectively. The difference from the standard rate constant k₀ ? 0.100 cm.s^?1 is explained by the effect of the cell-geometry characterized by the G-factor, so that k° = Gk*, where G ? 19 for our cell.     

Synthesis and characterization of epoxy resin of 9,9′-bis-(3,5-dibromo-4-hydroxyphenyl) anthrone-10 and its jute composite

Epoxy resin of 9,9′-bis-(3,5-dibromo-4-hydroxyphenyl) anthrone-10 (EANBr, EEW 490) was synthesized and was characterized by IR and ¹HNMR . EANBr and EPK3251 cured resin (EANBrC) were characterized by DSC and TGA at 10°Cmin^?1 under nitrogen atmosphere. Broad DSC endothermic transitions of EANBr (265.3 °C) and EANBrC (291.4 °C) are due to some physical change and further confirmed by no weight loss in their TG thermograms. EANBr and EANBrC are thermally stable up to 340 °C and 310 °C, respectively. EANBr has followed single step degradation kinetics, while EANBrC has followed two step degradation kinetics. EANBr followed apparently zero order kinetics, while EANBrC followed apparently second order (1.80) and first order (0.89) degradation kinetics, respectively. Ea and A values of EANBrC (299.7 kJmol^?1 and 6.32?×?10²⁰ s^?1) were found higher than that of EANBr (201 kJmol^?1 and 2.45?×?1013 s^?1) due to more rigid nature of EANBrC. The ΔS^* value of the first step degradation of EANBrC (146.3 JK^?1 mol^?1) was found much more than that of EANBr (4.6 JK^?1 mol^?1). Jute – EANBr composite (J-EANBr) was prepared by compression molding technique at 120 °C for 5 h and under 20 Bar pressure. The observed tensile strength, flexural strength, electric strength and volume resistivity of J-EANBr are 24.7 MPa, 19.0 MPa, 1.8 kVmm^?1 and 3.5?×?10¹² ohm cm, respectively. Water absorption in J-EANBr was carried out at 30 ± 2 °C against distilled water, 10% NaCl, 10% HCl, 10% HNO₃, 10% H₂SO₄, 10% NaOH, and 10% KOH and also in boiling water. The equilibrium time and equilibrium water content for J-EANBr in different environments are 384–432 h; 12.7–15.2%, respectively. The observed equilibrium water content and diffusivity trends of J-EANBr are KOH>H₂SO₄>HCl>NaOH>H₂O>NaCl and H₂O>NaCl>NaOH>H₂SO₄>HCl>KOH, respectively. Good thermo-mechanical, electrical properties and excellent hydrolytic stability of J-EANBr may be useful for high temperature applications in diverse fields.     

Ni0.4Co x Cd0.6 − x Fe2O4 ferrites as prepared by autocombustion synthesis

Ni_0.4Co _x Cd_0.6?x Fe₂O₄ ferrites (x = 0.0, 0.2, 0.4, and 0.6) were prepared by autocombustion synthesis and characterized by XRD, SEM, and other physical methods. XRD reveals the formation of spinel structure without any impurity phase. With increasing x, the lattice parameter was found to decrease from 8.60 to 8.37 Å. The FTIR spectra show the presence of tetrahedral site (at 571.12 cm^?1) and octahedral site (at 407.07 cm^?1). SEM images indicated the formation of agglomerated grains with a size of about 4.3 μm. The resistivity of the ferrites was found to decrease from 24.53 to 10.02 × 10⁸ Ω cm while the drift mobility to increase from 2.30 to 4.41 × 10⁸ cm² V^?1 s^?1 with increasing x.     

Differences in catalytic liquefaction kinetics of corn stalk fractions

Biomass-based polyol obtained by chemical liquefaction technology is a potential substitute for polyether or polyester polyol in preparation of degradable polymers. To obtain the favorable biomass-based polyol products, one important emphasis is to reveal the liquefaction kinetics. The liquefaction kinetics of different corn stalk (CS) fractions, i.e. whole CS, ear husk and leaf blade, were investigated in this work. The liquefactions were catalyzed with sulfuric acid at 120–180 °C for 15–90 min. The results indicated that the apparent reaction rate constant (k), apparent activation energy (E), ΔG′, and ΔH′ of liquefaction reactions differed remarkably with different CS fractions. The highest k of 1.8 × 10^?4 s^?1 was obtained from ear husk liquefaction at 120 °C, which was twofold and 2.7-fold higher than those of whole CS and leaf blade, respectively. However, k is not correlated with the stalk heterogeneity at temperature over 120 °C. The calculated E _{ear husk}, E _{whole CS} and E _{leaf blade} were 65.88, 81.64 and 85.23 kJ mol^?1, respectively. ΔG′ and ΔH′ values of ear husk liquefaction reactions were lower than those of the other two fractions. This work was the first comparison of kinetics with different biomass fractions, casting light on the effect of heterogeneity on liquefaction, and suggesting that CS fractions should be given themselves optimum applications in future.     

The influence of the tunnel probability on the anodic oxygen evolution and other redox reactions at oxide covered platinum electrodes

Potentiostatic and galvanostatic pulse measurements were carried out to investigate the anodic oxygen evolution at platinum electrodes in 1N H₂SO₄ in dependence on the oxide layer thickness d and the electrode potential ε. The thickness d (1·5–10 Å) was obtained from cathodic charging curves. Further, the temperature dependence (0°–81°C) was evaluated from Bowden's measurements. Summarizing, the current i_o2 follows the relation, log i = A - (E⁰_a - αFη)/2·3 RT - d/d_o. The experimental activation energy E_o = E^o_a = αFη decreases linearly with increasing overvoltage η. The linear decrease of log i with increasing d, which is given by the term d/d_o, is correlated to the probability of the quantum mechanical tunnel transition of the electron from adsorbed ions, OH^?_ad or O^2?_ad respectively, through the oxide layer to the metal. Similar effects of the oxide layer thickness on the current density were observed in the case of the oxygen evolution at iridium, the CO-oxidation on platinum, and the reduction of Cl^? and Ce⁴⁺ at platinum. In these cases a rate determining electron transfer through the oxide layer is also assumed.     

Ultrasound assisted synthesis of Gd and Nd doped ceria electrolyte for solid oxide fuel cells

In this study, the ceramic powders of Ce_1?xGd_xO_2?x/2 and Ce_1?xNd_xO_2?x/2 (x=0.05, 0.10, 0.15, 0.20 and 0.25) were synthesized by ultrasound assisted co-precipitation method. The ionic conductivity was studied as a function of dopant concentration over the temperature range of 300–800 °C in air, using the impedance spectroscopy. The maximum ionic conductivity, σ_800 °C=4.01×10^?2 Scm^?1 with the activation energy, E_a=0.828 kJmol^?1 and σ_800 °C=3.80×10^?2 Scm^?1 with the activation energy, E_a=0.838 kJmol^?1 were obtained for Ce_0.90Gd_0.10O_1.95 and Ce_0.85Nd_0.15O_1.925 electrolytes, respectively. The average grain size was found to be in the range of 0.3–0.6 μm for gadolinium doped ceria and 0.2–0.4 μm for neodymium doped ceria. The uniformly fine crystallite sizes (average 12–13 nm) of the ultrasound assisted prepared powders enabled sintering of the samples into highly dense (over 95%) ceramic pellets at 1200 °C (5 °C min^?1) for 6 h.     

Kinetics of aluminium deposition from aluminium chloride—alkali chloride melts

The kinetics of aluminium deposition from NaClAlCl₃ and NaClKClAlCl₃ melts (c_AlCl3 < 0.4 mol%) was studied by linear sweep voltammetry and potential step amperometry. The reduction of AlCl₃ on tungsten and aluminium electrodes was found to be diffusion controlled. The diffusion coefficients of AlCl₃ were: 3.5 × 10^?5 cm² s^?1 at 820°C in NaClAlCl₃, 2.7 × 10^?5cm²s^?1 at 825°C, and 2.1 × 10^?5cm²s^?1 at 705°C in KClNaClAlCl₃. The rate constant for AlCl₃ reduction at these conditions was found to be in the order of 0.2 cm s^?1, in good agreement with extrapolated literature data.     

Fabrication and characterization of MOCVD (In1-xAlx)2O3 (0.1≤x≤0.6) ternary films

A series of (In_1-xAl_x)₂O₃ (0.1 ≤ x ≤ 0.6) films with tunable bandgap were grown on MgO (100) substrates by MOCVD. The influences of chemical compositions and growth temperatures on the film properties were studied systematically. XRD analyses indicated that the film quality degraded from crystalline to amorphous structure as Al concentration (x) increased. The (In_1-xAl_x)₂O₃ films prepared at 700 °C exhibited better film crystallinity than those of the ones grown at 600 °C. The films prepared at 700 °C with x = 0.1–0.3 showed an epitaxial In₂O₃ <111> orientation with the corresponding growth relationship of In₂O₃ (111)∥MgO (100). The film with x = 0.2 exhibited the best crystallinity and the largest grain size of 25.9 nm. The Hall mobilities and resistivities of the films were influenced evidently by Al concentrations. The Hall mobility showed a monotonous decrease from 12 to 1.1 cm²V^?1s^?1 as x increased from 0.1 to 0.6. The lowest resistivity of 9.2 × 10^?3 Ω cm was acquired for the film with x = 0.2. The average transmittances in the visible region for all the films were beyond 83%. The bandgap of the (In_1-xAl_x)₂O₃ films can be regulated in the range of 3.85–4.88 eV by changing Al concentrations from 0.1 to 0.6.     

Liquefaction of partially dried and oxidized coals: 1. Coal drying and oxidation

Belle Ayr subbituminous coal was dried with gases including nitrogen, air, and nitrogen-air mixtures (simulated flue gases) to study the effect of drying on the coal characteristics in preparation for subsequent liquefaction experiments. Drying was carried out in micro-, laboratory- and bench-scale units at temperatures from ambient to 200 °C. The net moisture-free oxygen content of the coal increased with time and temperature to 3 wt%. Volatile oxygen-containing species, other than carbon oxides, that may have been released during drying were not investigated as the objective was to characterize oxidation kinetics and changes in coal properties. Two distinct kinetic regimes of oxygen consumption were observed during drying; an initial high-rate period of E_A?42–55 kJ mol^?1 followed by one of low rate, E_A?13 kJ mol^?1. A Powhatan No. 5 (Pittsburgh seam) bituminous coal, which initially had much lower oxygen content than the Belle Ayr coal (7.9 versus 23.3 wt%), gave analogous drying and oxidation results; however, the maximum net moisture-free oxygen uptake was ≈8 wt%.     

Electrically conductive polymer composites: polymerization of acetylene in polyethylene

Composites of low density polyethylene, LDPE, and polyacetylene, (CH)_x, were prepared by polymerization of acetylene in LDPE films impregnated with a $\text{Ti(OBu)}{}_4\text{Et}{}_3\text{Al}$ Ziegler-Natta catalyst. LDPE films were immersed in a toluene solution of this catalyst at 70°C to accomplish impregnation. Polymerization of acetylene in the LDPE films was carried out at 100°–110°C. The resulting composite films remain flexible and tough upon prolonged air exposure and those containing <ca. 5 wt.% (CH)_x soften upon heating to 120°–160°C. The films can be rendered conductive upon exposure to a 2 wt%. solution of l₂ in pentane. Ultimate conductivities of ca. 10Ω^?1cm^?1 can be obtained. The conductivities of the doped composites decay more slowly as compared with l₂-doped (CH)_x films. The synthetic approach, with some simple modifications, can be used in the construction of many electrically conductive, all-polymer composites having a combination of desirable physical, mechanical and electrical properties.     

A kinetic study of the isothermal degradation process of Lexan® using the conventional and Weibull kinetic analysis

The degradation process of commercial grade Lexan® was investigated by thermogravimetric technique under isothermal experimental conditions at four different operating temperatures: 375 °C, 387.5 °C, 400 °C and 425 °C. The kinetic triplet (E _a , A, f(α)) was determined using conventional and Weibull kinetic analysis. The applied kinetic procedure shows that the investigated degradation process can be described by two-parameter autocatalytic ?esták–Berggren (SB) reaction model. It was established that the degradation process of Lexan® can be described by the following kinetic triplet: E _a? =?158.3 kJ mol^?1, A?=?8.80?×?10⁹ min^?1 and f(α)?=?α ^0.33 (1???α)^1.62. It was established that the operating temperature has an influence on the values of SB reaction orders (m and n) (0.27?m?n??1, represent the composite value from a complex degradation reaction and can not compare with the dissociation energy of the weak bonds in bisphenol-A polycarbonate. Also, it was concluded that the Weibull shape parameter (β) shows that the considered process occurs under the same reaction mechanism, independently on operating temperature (T), i.e. the change of rate-limiting step does not occur (β?ddf) of apparent activation energies for considered degradation process. On the other hand, it was shown that the experimentally evaluated density distribution function of apparent activation energies represents the intermediate case between the calculated density distribution functions at 375 °C and 425 °C.     

Annealing effect on temperature coefficient of resistivity in La1−xSrxMnO3 ceramics

We investigated annealing effects of La_1?xSr_xMnO₃ (x = 0–0.6) on electrical resistivity and the temperature coefficient of resistivity (TCR). The annealed samples’ resistivity was lower than those of non-annealed samples. For example, annealing changed the resistivity of x = 0.3 at 25 °C from 4.50 × 10^?5 to 3.71 × 10^?5 Ω m. Remarkable difference in TCR was observed after annealing, for x = 0.3, 0.45, and 0.5. For x = 0.3, the TCR after annealing was 4000 ppm/°C, which was 1250 ppm/°C greater than that before annealing. We investigated (1) crystal phase, (2) Mn average valence, (3) Mott insulator–metal transition temperature, and (4) microstructure. The microstructure was remarkably varied for annealed x = 0.3 and 0.5. The average grain size of the x = 0.3 increased from 1.60 up to 2.38 μm. Results show that annealing affects resistivity and TCR because of grain growth during annealing.     

Linear sweep voltammetry of manganate(VII), manganate(VI), and manganate(V) in alkaline media

Electrochemical reactions were assigned to the voltammetric waves obtained in alkaline KMnO₄ and K₂MnO₄ solutions. Plots of i_p (AC°ν^{$\text{1}\text{2}$})^?1 and i_api_cp^?1 νs log ν indicate that at slow potential scan rates in MnO^?₄ solutions ranging from 0·07 to 0·19 F in NaOH the first step in MnO^?₄ reduction is a l-electron reversible charge transfer with no coupled chemical reaction; at fast scan rates (? V s^?1 the process becomes quasi-reversible. The standard rate constant and the activation energy for the MnO^?₄/MnO^2?₄ charge transfer step were estimated. Plots of i_p (AC°ν^{$\text{1}\text{2}$})^?1 and i_api_cp^?1 νs log ν indicate that in 4·O F KOH and at potential scan rates between 0·005 and 2·V s^?1 the reduction of MNO^2?₄ to MnO^3?₄ is a reversible charge transfer with no coupled chemical reaction. The diffusion coefficients of MnO^?₄ and MnO^2?₄ in alkaline solutions are reported.     

Potentiometric and polarographic studies of cadmium(II) complexes with tetraethylenepentamineheptaacetic acid

Stability constants for cadmium(II) complexes with tetraethylenepentamineheptaacetic acid (TPHA, H₇L) were determined by the pH titration method. In an aqueous solution (μ = 0.1), three complex species, CdH₂L, CdHL and CdL are confirmed. The structure of uninuclear complexes are discussed. The formation constants of the complexes stated above have been calculated as follows (at 25 ± 0.1°C): log K_CdL = 15.35, log K_CdHL = 13.33 and log K_CdH2L = 7.89. The polarographic behaviour of the cadmium(II) in the presence of TPHA was studied over the pH range 3–5. Mechanisms of the electrode processes were elucidated and electrochemical kinetic parameters were evaluated from dependence of the half-wave potentials on the hydrogen ion and TPHA concentration. In the presence of an excess of TPHA, the wave B is assigned to the irreversible reductions of the complex, CdH₂L^3? (pH range 3–4) or CdHL^4? (pH range 4–5). The electrode reaction can be written:

and

Where k_e (the rate constant) = 2.3 × 10^?2 cm s^?1 and k′_e = 1.59 × 10^?4 cm s^?1. The other polarographic methods were also used in the elucidation of the electrode process.     

Characterization of aluminum gallium oxide films grown by pulsed laser deposition

Aluminum gallium oxide (AGO) films were prepared on conventional c-plane sapphire by pulsed laser deposition (PLD). In the current PLD-AGO studies, target composition or growth temperature is usually the main deposition variable, and the other growth conditions are fixed. This would make it difficult to fully understand the theory and characterization of AGO films. In this study, several growth parameters such as target composition, gas atmosphere, laser repetition frequency, growth pressure, and substrate temperature (T_s) were all modulated to realize and optimize the AGO growth. When the (Al_xGa_1-x)₂O₃ target with the Al content larger than 20?at% was used, a serious target poisoning phenomenon occurred, leading to the extremely unstable growth rate. In comparison to the AGO film grown with argon atmosphere, the higher transparency was reached in the film prepared with oxygen atmosphere due to the relative abundance of oxygen. Because of the homogeneous oxygen reduction, the AGO film with the higher crystal quality was obtained at a higher laser repetition frequency. With an increment of growth pressure, the Al content of AGO film was increased. The growth of AGO film at the higher T_s would cause the higher bandgap value, smoother surface, and growth rate degradation. Additionally, the crystal quality of AGO film can be also improved both by increasing the growth pressure and T_s. The better characterization can be reached in the AGO film grown using the (Al_0.05Ga_0.95)₂O₃ target with oxygen atmosphere at the working pressure of 2?×?10^?1 Torr, the laser repetition frequency of 10?Hz, and the T_s of 800?°C. When the metal-semiconductor-metal photodetector fabricated with this AGO active layer, the best performance including the photocurrent of 7.56?×?10^?8 A, dark current of 1.59?×?10^–12 A, and photo/dark current ratio of 4.76?×?10⁴ (@5?V and 240?nm) were achieved.     

Evaluation of mixed‐conducting lanthanum‐strontium‐cobaltite ceramic membrane for oxygen separation

In this study, La_0.4Sr_0.6CoO_3‐δ (LSC) oxide was synthesized via an EDTA‐citrate complexing process and its application as a mixed‐conducting ceramic membrane for oxygen separation was systematically investigated. The phase structure of the powder and microstructure of the membrane were characterized by XRD and SEM, respectively. The optimum condition for membrane sintering was developed based on SEM and four‐probe DC electrical conductivity characterizations. The oxygen permeation fluxes at various temperatures and oxygen partial pressure gradients were measured by gas chromatography method. Fundamental equations of oxygen permeation and transport resistance through mixed conducting membrane were developed. The oxygen bulk diffusion coefficient (D_v) and surface exchange coefficient (K_ex) for LSC membrane were derived by model regression. The importance of surface exchange kinetics at each side of the membrane on oxygen permeation flux under different oxygen partial pressure gradients and temperatures were quantitatively distinguished from the oxygen bulk diffusion. The maximum oxygen flux achieved based on 1.6‐mm‐thick La_0.4Sr_0.6CoO_3‐δ membrane was ～4.0 × 10^?7 mol cm^?2 s^?1at 950°C. However, calculation results show theoretical oxygen fluxes as high as 2.98 × 10^?5 mol cm^?2 s^?1 through a 5‐μm‐thick LSC membrane with ideal surface modification when operating at 950°C for air separation. © 2009 American Institute of Chemical Engineers AIChE J, 2009     

Effect of radiation dose on the thermal degradation of poly(ethylene terephthalate) fabric

The effect of radiation dose (10–30 kGy) on the thermal decomposition of poly(ethylene terephthalate) was studied using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and X‐ray diffraction (XRD) analysis. The TGA and DSC were carried out in a flowing nitrogen atmosphere at heating rates of 5 and 30°C/min for TGA and 10°C/min for DSC. The degradation process was composed of three overlapping stages. The second stage, at which a rapid degradation occurs, was studied in detail. The process was found to follow a second‐order kinetics and was independent of radiation dose or heating rate. The reaction rate constant (k) was found to depend on the heating rate and iradiation dose. The apparent activation energy (Q) and the logarithm of the preexponential rate constant (log A) were found to decrease linearly with the increase in dose at rates of 3.32 kJ mol^?1 kGy^?1 and 0.177 s^?1 kGy^?1 with intercepts of 249 kJ/mol and 12.26 s^?1 for Q and log A of unirradiated fabric, respectively. A direct relationship was found between the percentage decrease in Q and log A and the percentage decrease in the temperature corresponding to 50% conversion (T_50%) for samples irradiated at different doses. It was found that a decrease in T_50% by 1% resulted in a decrease in Q and log A by 1.855 and 2.1%, respectively. Changes in Q and log A resulting from radiation, mechanical and thermal treatments, or their combinations can be predicted from the shift in T_50%. The history of the fibers substantially affected the thermal properties. DSC and XRD studies revealed changes in the fabric crystallinity. DSC measurements indicated a linear increase in heat of fusion with dose increase at a rate of 0.855 kJ kg^?1 kGy^?1. XRD analysis confirmed structural changes, rearrangement by plane rotations, and formation of compact crystalline lattice with patterns characterizing irradiated samples. An attempt to explain the dependency of the apparent activation energy on dose was given. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3710–3720, 2004     

Thermal-stability of electric field-induced strain and energy storage density in Nb-doped BNKT-ST piezoceramics

In this work, the relationship between the structural mechanisms and macroscopic electrical properties of the Nb-modified 0.96(Bi_0.5Na_0.84K_0.16TiO₃)–0.04SrTiO₃ (BNKT–ST) system were elucidated by using temperature dependent and in situ synchrotron X-ray diffraction (XRD) techniques. For the composition x?=?0.0175, a large-signal piezoelectric coefficient (S_max/E_max?=?d₃₃*) of 735 pm?V^?1 at 6?kV mm^?1 was observed at room temperature. Interestingly, at a higher temperature of 110?°C, the sample still showed a large d₃₃* of 570 pm V^?1. Furthermore, the temperature-invariant electrostrictive coefficient for this sample was found to be 0.0285?m⁴?C^?2 over the temperature range of 25–170?°C. Moreover, the energy density for x?=?0.030 sample was ～1.0?J?cm^?3 with an energy storage efficiency of ?70% in the temperature range of 25–135?°C. These results suggest that the synthesized Nb-modified BNKT–ST system is promising for the design of ceramic actuators as well as capacitor applications.     

High CO2 resistance of indium-doped cobalt-free 60 wt.%Ce0.9Pr0.1O2-δ-40 wt.%Pr0.6Sr0.4Fe1-xInxO3-δ oxygen transport membranes

The oxygen transport membrane (OTM) has huge application prospects in gas separation and carbon neutralization based on oxygen enriched combustion. In this paper, the family 60 wt.%Ce_0.9Pr_0.1O_2-δ-40 wt.%Pr_0.6Sr_0.4Fe_1-xIn_xO_3-δ (CPO-PSF_1-xI_xO, x = 0.01, 0.025, 0.05, 0.075, 0.1) cobalt-free dual-phase MIEC OTMs doped with indium have been successfully prepared by Pechini method. The phase structure, surface morphology, element distribution, oxygen permeability, and long-term operation stability of these OTMs are systematically explored. Among these OTMs, the champion oxygen permeable flux of CPO-PSF_0.99I_0.01O reaches 1.07 mL min^?1·cm^?2 and 0.80 mL min^?1·cm^?2 at 1000 °C under air/He gradient and air/CO₂ gradient. Meanwhile, CPO-PSF_0.99I_0.01O maintains the value of 0.80 mL min^?1·cm^?2 steadily at 1000 °C for 100 h when pure CO₂ as the sweep gas. The surface element distribution and phase structure of the OTMs after long-term oxygen permeability reaction are investigated by XRD, SEM combining with EDS, where the spent membranes retain the same structure and component as the fresh membranes, demonstrating that the In-doped OTMs have an excellent CO₂ tolerance. Suitable indium substitution for iron of these OTMs not only improves the oxygen permeability, but also maintains the long-term reaction stability of the material.