Citrate Method Research Articles

Large Electrocaloric Effect in Lead-Free (Ba0.85Ca0.15)(Zr0.1Ti0.9)O₃ Ceramics Prepared via Citrate Route.

The 1 wt % Li-doped (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 (BCZT-Li) ceramics prepared by the citrate method exhibit improved phase purity, densification and electrical properties, which provide prospective possibility to develop high-performance electrocaloric materials. The electrocaloric effect was evaluated by phenomenological method, and the BCZT-Li ceramics present large electrocaloric temperature change ∆T, especially large electrocaloric responsibility ξ = ∆Tmax/∆Emax, which can be comparable to the largest values reported in the lead-free piezoelectric ceramics. The excellent electrocaloric effect is considered as correlating with the coexistence of polymorphic ferroelectric phases, which are detected by the Raman spectroscopy. The large ξ value accompanied by decreased Curie temperature (around 73 °C) of the BCZT-Li ceramics prepared by the citrate method presents potential applications as the next-generation solid-state cooling devices.

Soot Oxidation Activity of Redox and Non-Redox Metal Oxides Synthesised by EDTA–Citrate Method

In the present study, redox (CeO2, SnO2, Pr6O11 and Mn3O4) and non-redox (Gd2O3, La2O3 ZrO2 and HfO2) metal oxides were successfully synthesised using the EDTA–citrate complexing method and tested for soot oxidation activity. The characterization of the metal oxides is carried out using FTIR, XRD, BET surface area, pore volume analyser, SEM and TEM. The redox nature and metal–oxygen bond information of the metal oxides are obtained from XPS analysis. In redox metal oxides, three critical parameters [lattice oxygen binding energy, reduction temperature and Δr (ionic size difference of the corresponding metal oxide oxidation states)] govern the soot oxidation activity. Among the redox metal oxide samples, Mn3O4 and Pr6O11 samples showed lower binding energy for oxygen (Oβ—529.4, 528.9 eV respectively), lower reduction temperature (Tα—317 and 512 °C respectively) and have smaller Δr value (9 pm and 17 pm respectively). Thus, displayed a better soot oxidation activity (T50 = 484 and 482 °C respectively) than compared to other redox metal oxides. Among the non-redox metal oxides, HfO2 sample displayed higher BET surface area (21.06 m2/g), lattice strain (0.0157), smaller ionic radius (58.2 pm) and higher relative surface oxygen ratio (58%) and thus resulted in a significantly better soot oxidation activity (T50 = 483 °C) than compared to other non-redox metal oxides.

Some Aspects on Synthesis and Characterization of Cobalt Aluminate Spinel Structure

Spinel based aluminates like compounds are found to have various applications as luminescent material, pigment, catalyst, electrodes and so on. Such compounds are observed to be synthesized by various processes like solid state method, sol-gel route, combustion, glycine, citrate methods, microwave assisted processing and others. The spinel compounds synthesized are noted to be identified by phase analysis, FTIR spectral analysis. In some cases, thermal studies of precursors are carried to obtain crystallization zone. Morphological analyses are carried by means of microscopic studies for compounds synthesized by different routes. Some important observations are discussed in brief for the spinel aluminates.

The Karyotype ofPlestiodon anthracinus(Baird, 1850) (Sauria: Scincidae): A Step Toward Solving an Enigma

The cosmopolitan lizard genus Eumeces was first revised in 1936 and consisted of 15 species-groups comprising a total of 50 species. Nine species in North America were later recognized as belonging to the genus Plestiodon and all contained the diploid chromosome number of 26. Modern cladistic techniques indicated that Plestiodon anthracinus (Coal Skink) was near the ancestral form for the fasciatus group. We employed the hypotonic citrate method to study chromosomes of 5 Coal Skink specimens from Louisiana and Arkansas and found them to have a diploid number of 24 (12 macrochromosomes, 12 distinctly smaller chromosomes, all biarmed) and a fundamental number of 48. The diploid number of 24 is probably derived by some chromosome rearrangements in the evolution of Plestiodon and of the Plestiodon anthracinus group.

Selective catalytic oxidation reaction of p-xylene on manganese–iron mixed oxide materials

Mixed manganese iron oxides (Mn/Fe/O) as heterogeneous catalysts were prepared by hydrothermal treatment and citrate methods to be tested in the oxidation of p -xylene (PX) using as oxidation agent molecular oxygen, hydrogen peroxide, and tert -butyl hydroperoxide. Preparation of mixed Mn Fe oxide by the citrate method releases materials with smaller particle size and lower degree of crystallinity as compared with the hydrothermal one, which further leads to a higher activity toward the oxidation of PX. A conversion of PX of 98% and a yield in p -toluic acid of 93% were obtained in the presence of Mn/Fe/O prepared by the citrate method using tert -butyl hydroperoxide as an oxidizing agent. Des oxydes mixtes de manganèse et de fer destinés à être utilisés comme catalyseurs hétérogènes ont été préparés par traitement hydrothermal et par la méthode citrate pour être testés dans l'oxydation du p -xylene, en utilisant comme agent d'oxydation l'oxygène moléculaire, le peroxyde d'hydrogène et l'hydroperoxyde de tert -butyle. La préparation de l'oxyde mixte de Mn Fe par la méthode citrate conduit à des matériaux ayant une taille de particules plus petite et une cristallinité moins importante en comparaison de ceux synthétisés selon l'autre méthode, ce qui a entraîné une activité élevée dans l'oxydation du p -xylène. Une conversion du p -xylene de 85% et une sélectivité vis-à-vis de l'acide p -toluique de 72% ont été obtenues en présence du catalyseur Mn/Fe/O préparé par la méthode citrate, en utilisant comme agent d'oxydation l'hydroperoxyde de tert -butyle.

A mathematical investigation of the Turkevich organizer theory in the citrate method for the synthesis of gold nanoparticles

Gold nanoparticles are commonly manufactured by the citrate reduction method, a synthesis method pioneered by Turkevich et al. (1951). Based on their experimental evidence, Turkevich et al. (1951) advanced the organizer theory, a nucleation-growth synthesis mechanism. Subsequently, Kumar et al. (2007) developed a mathematical model for the description of the synthesis, basing it on such a theory. However, this model has not been thoroughly tested. Recently, contrary to the evidence provided by Turkevich et al. (1951), other mechanistic descriptions of the synthesis, which emphasize the role of the pH of the solution, have been advanced in the literature. In this paper, we investigated the model of Kumar et al. (2007) for different conditions of pH, temperature and initial reactant concentrations. To solve the model, we used the numerical code Parsival, which is used for solving population balance equations. We tested the model for different synthesis conditions studied experimentally by various researchers, for which results are available in the literature. The model poorly predicted the experimental data because the Turkevich organizer theory does not account for the acid-base properties of chloroauric acid and sodium citrate. A new model, with a more accurate mechanistic description of the synthesis and of the chemistry involved, is therefore required.

On A-doping strategy for tuning the TWC catalytic performance of perovskite based catalysts

Several perovskites of the type La1-xAxCo0.5Cu0.5O3 (A=K, Sr, Ba; x=0, 0.25, 0.5) and a Sr-doped understoichiometric one, have been prepared by citrate method aiming at application as noble metals free catalysts for automotive application. The catalysts have been characterized by BET, X-ray diffraction (XRD), Temperature Programmed Reduction (TPR), X-Ray Photoelectron Spectroscopy (XPS), and Scanning Electron Microscopy (SEM) and the effect of A-doping has been investigated. The catalytic activity was studied in model reactions (CO oxidation, CO assisted NO reduction), and in a complex three way catalysts (TWC) mixture approaching automotive exhaust composition at both stoichiometric and O2-limiting conditions and the obtained results are discussed in relation with characterization results. A-doping induces the formation of highly dispersed cubic CuO particles, as observed in the understoichiometric samples. Doping also influences the surface segregation. La segregation is observed in the undoped LaCo0.5Cu0.5O3 sample whereas K is surface segregated in La0.75K0.25Co0.5Cu0.5O3; Co segregates in the Ba-doped perovskite and Sr in the understoichiometric La0.35Sr0.35Co0.5Cu0.5O3. The reducibility (TPR) is altered by A-doping. The reactivity results suggest that in simple CO+O2 and CO+NO mixtures the activation temperature is increased by any doping, but at 400°C the conversion in the CO assisted NO reduction is not significantly different with respect to the one obtained in the undoped catalyst. Activity with a more complex mixture, simulating actual engine exhaust, reveals the interesting activity of the Sr-doped catalysts, that outperform LaCo0.5Cu0.5O3 at both stoichiometric and O2-lean conditions. NO reduction can be achieved at lean O2 conditions, where it is quantitative from 400°C. The possibility to reach similar or better activity by replacing the use of La, which is a Rare Earth Element, by using Sr is particularly interesting. Stability at high temperatures and at fast fluctuations of O2 in inlet stream for 50% Sr-doped catalyst confirms these results.

Pt@Ag and Pd@Ag core/shell nanoparticles for catalytic degradation of Congo red in aqueous solution

Platinum/silver (Pt@Ag) and palladium/silver (Pd@Ag) core/shell NPs have been synthesized in two steps reaction using the citrate method. The progress of nanoparticle formation was followed by the UV/Vis spectroscopy. Transmission electron microscopy revealed spherical shaped core/shell nanoparticles with average particle diameter 32.17nm for Pt@Ag and 8.8nm for Pd@Ag. The core/shell NPs were further characterized by FT-IR and XRD. Reductive degradation of the Congo red dye was chosen to demonstrate the excellent catalytic activity of these core/shell nanostructures. The nanocatalysts act as electron mediators for the transfer of electrons from the reducing agent (NaBH4) to the dye molecules. Effect of reaction parameters such as nanocatalyst dose, dye and NaBH4 concentrations on the dye degradation was investigated. A comparison between the catalytic activities of both nanocatalysts was made to realize which of them the best in catalytic performance. Pd@Ag was the higher in catalytic activity over Pt@Ag. Such greater activity is originated from the smaller particle size and larger surface area. Pd@Ag nanocatalyst was catalytically stable through four subsequent reaction runs under the utilized reaction conditions. These findings can thus be considered as possible economical alternative for environmental safety against water pollution by dyes.

Synthesis of nonspherical nanoparticles by reducing silver neodecanoate extract with benzyl alcohol

A method for synthesizing nonspherical silver nanoparticles by reducing liquid extract of silver neodecanoate in benzyl alcohol has been developed. The method is simple and does not require the use of polyvinylpyrrolidone, sodium citrate or special methods using pre-synthesized seeds. The obtained particles have been investigated by the methods of electron microscopy, X-ray diffraction, and differential-thermogravimetric analysis. It has been found that triangular and hexagonal plates, as well as particles of pentagonal form and polyhedrons, are formed as a result of the reduction. The sizes of the obtained plates, depending on the synthesis conditions, vary from 80 nm to 2 μm. The method is promising for the industrial production of silver nano- and microplates.

Double Layered CeO2-Co3O4-CuO Based Anode for Direct Utilisation of Methane or Ethanol in SOFC

Solid oxide fuel cells have been subject of many developments especially concerning alternative fuels such as hydrocarbons and alcohols, mainly because these devices can convert chemical potential into electricity with high efficiencies. In addition, the direct utilisation of hydrocarbons or alcohols as fuels increases the feasibility of SOFC market penetration. However, issues such as coking and clogging by carbon formation must be overcome before the technology can be safely delivered to final consumers. Therefore, the aim of this work was to develop an anode material capable of using methane or ethanol as fuels directly into the cell without any pre-reforming which could prevent carbon to deactivate the anode material. A bimetallic Ceria-based electrocatalyst was thus prepared using Cobalt and Copper oxides to enhance catalytic activity and electrical conductivity. Two different compositions were produced, a Cerium-rich composition with the molar proportion of Ce:Co:Cu – 2:1:1 and a Cobalt-rich one, Ce:Co:Cu – 1:2:1. The electrocatalyst powder was synthesised by the amorphous citrate method and characterised by X-Ray diffraction (XRD), Rietveld refinement, and temperature-programmed reduction (TPR). The powders produced were pelletised, sintered, and then submitted to Van der Pauw 4-probe DC conductivity tests. ScCeSZr electrolyte-supported cells were produced with a Lanthanum Strontium-doped manganite cathode screen printed onto the electrolyte. The anode was comprised with a double layer of the aforesaid compositions and a Sc10Ce1Zr + CeO2 inner layer that provided more stability between the electrolyte and the anode. The cell was tested under hydrogen as fuel and oxygen as oxidant from 750 to 850 ˚C, and then with anhydrous methane and ethanol separately as fuels at 850 ˚C. After operation, the cell was submitted to Raman spectroscopy to assess any evidence of carbon deposition through the anode microstructure. Moreover, scanning electron microscopy was conducted to evaluate the anode morphology and conditions concerning its microstructure. XRD spectra showed that the desired bimetallic CeO2-Co3O4-CuO oxide was formed and Rietveld refinement indicated that the formation of solid solutions did not occur. TPR demonstrated the ability of both compositions to absorb hydrogen by reducing its oxides as expected. DC conductivity tests presented suitable values since the tests were taken over the oxidised sample. The cell could operate in hydrogen, methane or ethanol as fuels showing maximum power densities of approximately 400, 100 and 160 mW.cm–2, respectively, at 850 ˚C. Raman spectroscopy was performed over several spots on the cell during post-mortem analysis and no evidence of carbon deposition was found on the anode. SEM images showed a homogenous microstructure concerning surface morphology and pore distribution. Finally, it was found that the bimetallic electrocatalyst anode could utilise hydrocarbon fuels directly without pre-reforming and produce a reasonable power density with no evidence of carbon coking which shows that this material configuration is promising as anode for carbonaceous fuels.

Low temperature sintering and nonlinear dielectric properties of Li2O doped Ba0.6Sr0.4TiO3 ceramics derived from the citrate method

A nominal composition of Ba0.6Sr0.4TiO3 + 0.5 wt. % Li2O ceramic specimen was prepared from the citrate method. The addition of Li2O was found to be effective to reduce the sintering temperature of Ba0.6Sr0.4TiO3 ceramics, which was attributed to the formation of transient liquid phase. The ceramic specimen sintered at 900 °C showed a fine-grained microstructure with considerable densification and attained the relative density of 97%. The diffusion of Li2O into Ba0.6Sr0.4TiO3 lattice was found to have an evident effect on the dielectric properties of the ceramics. The specimen exhibited a dielectric constant of 1997 and a dielectric loss 0.67% at 10 kHz and zero bias-field together with a tenability of 27.8% and a FOM of 41 at 10 kHz and 30 kV/cm.

Deposition of NiO on 3 mol% yttria-stabilized zirconia and Sr0.96Y0.04TiO3 materials by impregnation method

The main purpose of this work was the synthesis of composite materials by deposition of nickel oxide on 3 mol% yttria-stabilized zirconia (3 mol% Y2O3–97 mol% ZrO2–YSZ) and Sr0.96Y0.04TiO3 (4 mol% Y-doped strontium titanate—SYTO) supports. Yttria-stabilized zirconia and yttrium-doped strontium titanate were obtained by modified citrate method. The deposition of nickel oxide was performed by impregnation method. All materials were impregnated with proper amount of nickel(II) nitrate aqueous solution to receive the 1 and 5 mass% of nickel in the final composite. The temperature-programmed reduction (TPR) was applied to analyze the reduction mechanism of deposited NiO. Three forms of nickel oxide: non-stoichiometric NiO1+x, hexagonal and cubic are postulated on the base of the TPR profiles and analysis of bonds length in nickel oxides structures. Moreover, TPR analysis shows that support strongly affects the reduction mechanism as a consequence of various interactions between NiO and YSZ/SYTO. In the case of YSZ, the nickel oxide reveals the tendency to deposit on the support surface, while using SYTO as the support, nickel oxide exhibits significant ability to react with doped strontium titanate and what is more important nickel incorporates into Sr0.96Y0.04TiO3 structure.

A comparative study of physical properties in Fe3O4 nanoparticles prepared by coprecipitation and citrate methods

AbstractMagnetite exhibits unique structural, electronic, and magnetic properties in extreme conditions that are of great research interest. In this work, the effects of preparation technique on X‐ray peak broadening, magnetic and elastic moduli properties of Fe3O4 nanoparticles prepared by coprecipitation (FcP‐NPs) and citrate (FC‐NPs) methods have been investigated. The structural characterization of the samples is evidence for a cubic structure with Fd‐3m space group. The Williamson‐Hall analysis was used to study crystallite sizes and lattice strain of the samples and also stress and energy density. In addition, the crystallite sizes are compared with the particle sizes and the magnetic core sizes obtained from TEM and VSM methods, respectively. In addition, the cation distribution obtained from calculated inversion parameter indicate that in the smaller particles, more amount of Fe2+ on the tetrahedral sites can be related to higher stress induced in the FcP‐NPs compared to the FC‐NPs. The saturation magnetization of the FcP‐NPs is almost two times bigger than the saturation magnetization of the FC‐NPs. It could be attributed to the decrease in the negative interaction on the octahedral site and also the magnetic moment on the tetrahedral site of the FcP‐NPs. The increase in force constants of the FC‐NPs determined by infrared spectra analysis compared to FcP‐NPs suggests the strengthening of their interatomic bonding. The values of shear and longitudinal wave velocities obtained from force constants have been used to determine the values of Young's modulus, rigidity modulus, bulk modulus, and Debye temperature. By comparison of the elastic results of FC‐NPs with the FcP‐NPs, we can observe that the elastic properties of the F‐NPs have been improved by synthesis method, while Poisson's ratio almost remains constant. In addition, using the values of the compliance sij obtained from elastic stiffness constants, the values of Young's modulus and Poisson's ratio along the oriented direction [hkl] have been calculated for the samples.

COx-free hydrogen production via decomposition of ammonia over Cu–Zn-based heterogeneous catalysts and their activity/stability

Cu–Zn mixed metal oxides were synthesized with a modified citrate method, supported on an Al2O3 substrate, and tested for ammonia decomposition process to attain a high-purity hydrogen generation for fuel cells. Alumina-supported catalytic materials prepared by wet impregnation technique exhibited the highest surface copper species dispersion along with an increase in distributed acidic and basic sites. TPD studies using NH3 and CO2 revealed the presence of the Lewis and Brønsted acidity and basicity. SEM demonstrated a uniform particle distribution and morphology, regardless of Cu/Zn ratio. Cu/ZnO/Al2O3 exhibited a superior conversion activity when compared to neat Cu–Zn, which may be due to an improved Cu–Zn synergistic effect, a smaller average bimetallic nanoparticle size, and moderate acid–base characteristics. TEM micrographs confirmed the round-shaped metallic particles, ranging up to 7nm in diameter and comprising both active copper oxide phases (Cu1+ and Cu2+), further investigated by EELS spectroscopy, as well as by XPS analysis. With reactions resulting in an effective first-order turnover (rate-determining step limitation), the apparent activation energies of (50–80)±5kJmol−1 were estimated in between 450 and 600°C which is in agreement with other commercial catalysts. All fabricated bi-functional catalysts exhibited a high long-term stability and hydrogen productivity; nonetheless, comprised no critical scarce raw resources (e.g. platinum-group metals), which is appealing for emerging chemically-bonded H2 storage and release be it in relation to production only (electrolysis) or with consumption (regenerative fuel cells).

Modification of Co/Cu nanoferrites properties via Gd3+/Er3+doping

Pure nanoparticles of the rare earth-substituted cobalt and copper ferrites with general formula Me Gd0.025 Er0.05 Fe1.925 O4 (Me = Co, Cu) were prepared by the chemical citrate method. X-ray diffraction, field emission scanning electron microscopy, BET analysis are utilized to study the effect of rare earth substitution and its impact on the physical properties of the investigated samples. Rare earth-doped cobalt shows type IV isotherm suggesting mesopore structure with its hysteresis loop. The estimated crystallite sizes are found in the range of 21.49 and 36.11 nm for the doped Co and Cu samples, respectively. The magnetic properties of rare earth-substituted cobalt and copper ferrites showed a definite hysteresis loop at room temperature. An increase in coercivity and a decrease in saturation magnetization were detected. This can be explained in view of weaker nature of the Re3+–Fe3+ interaction compared to Fe3+–Fe3+ interaction. Greater than 1.13-fold increase in coercivity (Hc = 2184 Oe) was observed in doped cobalt nanoferrite samples compared to copper (Hc = 1936 Oe). It was found that the decreasing in temperature leads to great improvement in the magnetic properties of the investigated samples. As the magnetic recording performance of the magnetic samples is improved for well-crystallized samples with nano-structural, the effect of rare earth substitution seems to be particularly valuable in this regard.

Effects of Composition on Dielectric Properties of (Ba,Ca)(Zr,Ti)O3 Ceramics for Energy Storage Capacitors

Ba1−xCaxZr0.2Ti0.8O3 (x = 0, 0.05, 0.10) and Ba0.95Ca0.05ZryTi1−yO3 (y = 0.20, 0.25, 0.30) ceramics have been prepared by a citrate method and their structure, energy storage density, ferroelectric phase transition behavior, and dielectric nonlinearity investigated. All specimens showed cubic perovskite structure at room temperature. The energy storage density of the specimens at given electric field of 120 kV/cm was similar at around 0.40 J/cm3. In contrast, the degree of relaxor behavior of the specimens varied with changing A- or B-site composition. Compared with increasing calcium content at A-site, increasing zirconium content at B-site more readily induced pronounced relaxor behavior. The dielectric constant of the specimens under bias electric field dropped to a common level at high field. Fitting the nonlinear dielectric response under bias field using a multipolarization mechanism model resolved the contributions of various polarization mechanisms. It turned out that the extrinsic contribution of polar nanoregions faded out within the low-field range, with intrinsic lattice phonon polarization governing the overall dielectric response at high field. Moreover, characteristic parameters of the polarization mechanisms were determined from the fitting. Based on these fitting results, the differing composition dependence of the energy storage density and relaxor behavior were explained.

Perovskite-based catalysts for tar removal by steam reforming: Effect of the presence of hydrogen sulfide

One of the greatest problems in biomass gasification processes is the conditioning of the produced synthesis gas, which contains various contaminants, including tar and hydrogen sulfide. Nickel catalysts, designed for steam reforming of aliphatic hydrocarbons (natural gas and nafta), are usually deactivated by coke deposition and sulfur poisoning. In this work, nickel and/or manganese catalysts derived from perovskites were prepared by the citrate method and characterized by X-ray diffraction, N2 physisorption and temperature programmed reduction. The catalysts were evaluated in the steam reforming of toluene, used as tar model compound, in the absence of H2S at 700 °C and in the presence of 50 ppm H2S at 800 °C. LaNi0.5Mn0.5O3 catalyst showed higher activity and stability in the absence of H2S. LaMnO3 catalyst, although less active in the absence of H2S, showed increased stability in the presence of H2S, with conversion of about 60%. H2 production was only observed in the absence of H2S.

Particle size dependence of the magnetic and magneto-caloric properties of HoCrO3

Magnetic and magneto-caloric properties of polycrystalline powder samples of HoCrO3 with four different particle sizes are reported here. The samples were prepared by citrate method and were annealed at 700, 900, 1100, and 1300 °C to yield average particle sizes of 60 nm, 190 nm, 320 nm, and 425 nm, respectively, as determined by the analysis of X-ray diffraction patterns and images obtained by scanning electron microscopy. Additional structural characterization was done using Raman spectroscopy. Measurements of the magnetization of the samples were done from 5 K to 300 K in magnetic fields up to 70 kOe. Analysis of the temperature dependence of the paramagnetic susceptibility in terms of the modified Curie-Weiss law, including the Dzyaloshinsky-Moriya (DM) interaction, show small but systematic changes in the Néel temperature TNCr of Cr3+ ions, exchange constant J, and the DM interaction with variation in particle size. However, below TNCr the largest size-dependent effects are observed at 5 K, and the measured magnitudes of coercivity field HC are 1930, 2500, 4660, and 7790 Oe for the 60 nm, 190 nm, 320 nm, and 425 nm size particles, respectively, which can be interpreted by a single domain model. Enhancement of the particle size gives about a fourfold increase in the magnitude of the energy product, HC * MS, where MS is the saturation magnetization. However, as the particle size rises, an opposite trend is observed in the max magnetic entropy (ΔSM = 8.73, 7.22, 7.77, and 6.70 J/kg K) and the refrigerant capacity (RC = 388, 354, 330, and 310 J/kg) for the 60 nm, 190 nm, 320 nm, and 425 nm size particles, respectively. These results suggest ways to optimize the properties of HoCrO3 for applications in magnetic storage and magnetic refrigeration.

A Mathematical Investigation of the Turkevich Organizer Theory in the Citrate Method for the Synthesis of Gold Nanoparticles

A Mathematical Investigation of the Turkevich Organizer Theory in the Citrate Method for the Synthesis of Gold Nanoparticles

Structural and redox features of La0.7Bi0.3Mn1−xCoxO3 nanoperovskites for ethane combustion and CO oxidation

AbstractIn this work, structural and catalytic properties of La0.7Bi0.3Mn1−xCoxO3 nanocatalysts with x=0.00, 0.25, 0.50, 0.75, and 1.00 prepared by citrate method are investigated. The structural characterization using X'Pert package and Fullprof program is an evidence for structural phase transition. The values of refined unit cell volume obtained from the Rietveld analysis show decreasing and increasing tendencies for values of x≤0.5 and x>0.5, respectively. The catalytic performance tests of the catalysts show that the samples x=0.00 and 0.25 have lower temperature of CO oxidation and C2H6 combustion, respectively.