Sol-gel Combustion Synthesis Research Articles

Improving cycling performance and high rate capability of LiNi0.5Mn0.3Co0.2O2 cathode materials by sol-gel combustion synthesis

The layered LiNi0.5Mn0.2Co0.2O2 (NMC532) material displays capacity loss and poor rate performance even though it is a widely used cathode in commercial Li-ion batteries (LIBs). In this work, the structural and electrochemical performance of the NMC532 cathode were optimized using the fuel-to-oxidizer ratio assisted sol-gel combustion synthesis (SCS). It was shown that the fuel-to-oxidizer ratio markedly influenced the exothermicity of the combustion reaction which affected the crystal structure, morphology, and electrochemical performance of the final NCM532 materials. The fuel lean (FL) composition produced NMC532 cathode materials with the biggest crystallite and particle sizes, less cation mixing degree and better layered structure compared with the fuel stoichiometric (FS) and fuel rich (FR) compositions. The FL cell presented an initial discharge capacity of 180 mAh g−1 and the highest capacity retention of 92.2 % when it was cycled at 0.1 C between 2.5 and 4.4 V. Also, the FL cell displayed exceptional rate capability with the average capacities reaching 180, 178, 175, and 173 mAh/g at current densities of 1 C, 3 C, 5 C, and 10 C, respectively between 3.0 and 4.6 V. The EIS tests and dQ/dV plots showed that the FL cell both had the least impedance and polarization. The superior electrochemical performance of the FL material was ascribed to its optimized structural properties. Furthermore, the electrochemical results also show the influence of voltage window and current density on the performance of the NMC532 cathode materials.

Soft sol–gel combustion synthesis: A potential route for functional nanocomposites of copper-based mixed valent oxides and cermet

The high reaction rate in the sol–gel combustion synthesis (SCS) often restricts precise control over the composition of mixed valent oxides in a single step. The current study overcomes this limitation by employing melamine—that forms a hydrogel with Cu(II)—as a novel fuel in the combustion synthesis. As opposed to the conventional SCS approach, the current synthesis occurs in a mild and controlled way under oxygen-lean conditions,wherein at and above 300 °C of calcination, a red-hot coke is found to form and persist for hours and hence termed as ‘soft sol–gel combustion synthesis’ (SSCS). Such a controlled synthesis is shown to be pivotal in obtaining a copper-based mixed-valent oxide/cermet nanocomposite system, comprising tunable levels of g-C3N4, in a single step. The phase compositions of the nanocomposites are modulated by varying calcination parameters like temperature and duration. These nanocomposites are thoroughly characterized for their microstructural, morphological, elemental, bandgap, and optical properties.Unique compositions are synthesized from the blend of Cu(II)–melamine complex gel with ZIF-8, in which formulations comprising different proportions of ZnO, CuO, Cu2O, metallic Cu and g-C3N4 have been obtained. Such multicomponent formulations post ball-milling exhibit notable photocatalytic activity in degrading organic pollutants and show high antibacterial efficacy against Escherichia coli under dark-light dual-mode conditions. Additionally, the SSCS approach has also been demonstrated for its versatility by synthesizing nickel-based cermet, which opens up numerous avenues for developing exotic material compositions for diverse applications in the realms of energy and environment.

Sol-gel combustion synthesis and near-infrared luminescence of Ni2+-doped MgAl2O4 spinel phosphor

Near-infrared phosphor converted light-emitting diode (NIR pc-LED) has many advantages over traditional NIR light sources, and has broad application prospects in night vision surveillance, non-destructive testing, bioimaging, and other fields. Phosphors are typically synthesized by the high-temperature solid-phase method as chunks or large granules, which need to be ground to small particles for practical application. This process introduces surface defects and reduces the luminous efficiency of phosphors. In this work, near-infrared phosphors composed of spinel MgAl2O4:Ni2+ with particle size less than 100 nm was synthesized in high-purity by sol-gel combustion method using nitrate salts with citric acid were used as raw materials. Under 365 nm excitation, MgAl2O4:Ni2+ phosphors emit broadband near-infrared luminescence of 1000–1600 nm with a width at half maximum of 237 nm. The optimal Ni2+ doping concentration was determined to be 1.5 mol% and the optimal sintering temperature was 1200 °C. The thermal activation energy of this phosphor was found to be 0.409 eV and the phosphor had good luminescence thermal stability. An NIR pc-LED device was assembled from the phosphor and commercially available near-ultraviolet LED, which showed a current-dependent increased of NIR luminescence up to 160 mA and an efficiency drop appeared with further increase of the current, suggesting a thermal dependent quenching may have occurred. On the other hand, the output of NIR luminescence increased nearly linearly with the increased of current when a 360 nm laser diode was used as the excitation light source, indicating the NIR phosphor has a very high fluorescence saturation threshold. Our study provides the utility for the sol-gel method in the preparation and the potential application of the nanoscale NIR-II phosphor materials.

Europium-doped strontium gadolinium oxide phosphor: Investigating structural and photoluminescence characteristics via sol-gel combustion synthesis

SrGd2O4 phosphors doped with Eu3+ were successfully synthesized through a sol-gel combustion method, covering a range of dopant concentrations from 0.25 mol% to 3 mol%. The structural analysis of these phosphor materials was comprehensively conducted utilizing various techniques, including X-ray powder diffraction analysis (XRD), Energy Dispersive X-ray (EDX), and Fourier-transform infrared spectroscopy (FTIR). In addition to unveiling the structural characteristics, these analyses provide valuable insights into the compositional aspects, enhancing our understanding of the synthesized SrGd2O4:Eu3+ phosphors across different doping levels. XRD analysis findings validate the successful generation of the intended SrGd2O4 host, demonstrating orthorhombic system structures consistent with JPCD card number 98-019-3592. FTIR analyses conducted on the phosphor samples not only identify bending modes but also reveal intricate details about small vibration bonds within the material. When excited by the 349 nm laser, SrGd2O4:xEu3+ phosphors exhibit distinct photoluminescence (PL) properties like red emission at 614 nm from Eu3+. From the emission spectra, one can clearly observe that Eu3+ with an ionic radius close to the Gd3+ ion preferentially occupies the symmetry sites of the host lattice. The optimal doping concentration was determined to be 0.5 mol%, as revealed by the data in our study. Additionally, a deeper understanding of the luminescence quenching mechanism was attained, pinpointing the involvement of dipole-dipole (d-d) energy transfer in this intriguing phenomenon. This optimal concentration not only enhances the material's properties but also underscores the pivotal role of d-d interactions in governing the luminescence behavior within the doped system.

Green mediated sol-gel auto combustion and solution combustion synthesis of calcium magnesium aluminate (CMA) nanoparticles: Modified carbon paste and nickel mesh electrodes for supercapacitor and sensor applications

Calcium Magnesium Aluminate (CMA) nanomaterials (NMs) were designed using a density functional theory (DFT) based materials project. Sol-gel and combustion techniques were used to prepare CMA nanoparticles and compared with characteristics and electrochemical studies with different electrodes like modified carbon paste and nickel mesh in this article. Structural characterizations using X-ray Diffraction (XRD) and Fourier Transform Infrared (FTIR) spectra were performed. Morphological characterizations using Scanning Electron Microscopy (SEM) and High-resolution Transmission Electron Microscopy (TEM) were carried out. Modified carbon paste electrodes and nickel mesh electrodes were developed using CMA NMs via sol-gel and combustion method, its electrochemical techniques such as Cyclic Voltammetry (CV), Linear Sweep Voltammetry (LSV) were compared for the sensitive detection of biomonitoring samples (i.e. uric acid, creatinine, ascorbic acid, riboflavin) and environmental contaminants (i.e. Lead nitrate and Cadmium nitrate). Specific capacitance (Csp) was calculated using CV curves for both modified carbon paste and nickel mesh electrodes found that, prepared nickel mesh electrodes by CMA NMs via sol-gel method exhibits comparatively maximum Csp value. Nickel mesh electrodes were further analysed galvanometric charge-discharge process via sol-gel and combustion technique. This report paves the way for tri-metal aluminate (CMA) design and development for electrochemical applications such as supercapacitors and sensors for the detection of various analytes.

Introducing Materials Science: Experimenting with Magnetic Nanomaterials in the Undergraduate Chemistry Laboratory.

Materials science research has expanded significantly in recent years; a multidisciplinary field, home to an ever-growing number of chemists. However, our general chemistry degree courses have not changed to reflect the rise in interest in this topic. In this paper, we propose a laboratory experiment for the undergraduate chemistry practical course, which may serve as a hands-on introduction to this field. The experiment involves the synthesis and characterization of magnetic materials via commonly employed techniques in materials science. Students begin by producing three metal ferrite spinels using a sol-gel combustion synthesis. They must then characterize the differing magnetic properties across their three samples using a magnetic susceptibility balance. In the second part of the experiment, students must create a ferrofluid via coprecipitation, from which they may observe the phenomenon of "spiking" in response to an external magnet. Additional data such as X-ray diffraction (XRD) patterns and transmission electron microscopy (TEM) images corresponding to these materials are also provided, and students are tasked with the interpretation of these data in their writeup report. Upon completion, students should gain a new-found understanding of materials science and its fundamental overlap with chemistry.

Sol–Gel Combustion Synthesis and Study the High Frequency Dielectric Properties of Copper Ferrite Nanoparticles

Sol–Gel Combustion Synthesis and Study the High Frequency Dielectric Properties of Copper Ferrite Nanoparticles

A simple and fast strategy for rare earth doped phosphors prepared by 980 nm laser thermal effect

The phosphors synthesize by the sol-gel method show low cost and good homogeneity, but it also requires furnace annealing at high-temperatures. This report uses a 980 nm laser annealing strategy to replace the furnace annealing in the sol-gel combustion synthesis. The fast laser annealing can improve the preparation efficiency of rare earth doped phosphor. Er3+/Li+ co-doped Y2O3 nanocrystals are synthesized by laser annealing strategy. The structures and spectral properties of the phosphors prepared by laser annealing are studied. The phosphors prepared by laser annealing have the same crystal structure and spectral properties as those organized by furnace annealing. In addition, phosphors can be heated into crystals using a high-power 980 nm laser. Under 980 nm excitation, the crystal prepared by laser annealing shows a much stronger fluorescence intensity than phosphors.

Sol–gel combustion synthesis and photocatalytic dye degradation studies of rare earth element Ce substituted Mn–Zn ferrite nanoparticles

This paper reports the impacts of cerium (Ce) substitution on morphological, magnetic and structural characteristics of Mn0.5Zn0.5CexFe2-xO4 (x = 0.0, 0.3 and 0.5) ferrites nanoparticles (NPs) prepared via sol gel combustion method. The crystalline structure, magnetic and morphological features were examined by powder X-ray diffraction, vibrating sample magnetometer and scanning electron microscope analyser individually. Magnetic hysteresis (M−H) loops of samples were determined to examine the magnetic properties of synthesized samples. Magnetic measurement shows that samples exhibit ferromagnetic behaviour at room temperature (RT). The magnetic properties are described in terms of cation substitution and grain size effect. The various concentration of synthesized photocatalyst such as Mn0.5Zn0.5Fe2O4, Mn0.5Zn0.5Ce0.3Fe1.7O4 and Mn0.5Zn0.5Ce0.5Fe1.5O4 NPs were analysed under visible light irradiation by the degradation of an aqueous solution of Congo red and Reactive Orange 16 dyes and the sample Mn0.5Zn0.5Ce0.3Fe1.7O4 NPs showed higher degradation percentage 97.25% and 98.42% respectively, than other compositions at 120 min with enhanced visible light absorption range. These performances expose that these nanomaterials are appropriate for high frequency applications.

Optimization of sol-gel combustion synthesis for calcium looping CO2 sorbents, part Ⅰ: Effects of sol-gel preparation and combustion conditions

The sol-gel combustion synthesis is a superior method to prepare high-performance CaO-based sorbent which is applicable for flue gas decarbonization and thermochemical energy storage. To optimize this synthesis, this study investigated different preparation variables in the sol-gel formation process and combustion process. The effects of these variables on the cyclic CO2 sorption performance, micromorphology, and physical parameters of the prepared pure CaO sorbents were studied. First, worse cyclic performance was shown when the H2O/Ca2+ molar ratio was over 100:1, and the optimal ratio was 80:1. Second, the citric acid/calcium nitrate ratio influenced the formation of the complex as well as the gas production and adiabatic flame temperature in the combustion process, and the optimal molar ratio was 1:1. Third, the NH4NO3 and Ca-based precipitate would be produced when the pH value of the precursor solution was over 3. The optimal pH value was 2, and the carbonation conversion of the prepared sorbent reached 99% in the 2nd cycle within the 10 min carbonation at 650 °C under 15% volume CO2. After 20 cycles, the conversion was 70.4%. Fourth, a higher heating rate facilitated better cyclic performance and the optimal heating rate was 10 °C/min. Finally, a higher initial ignition temperature accelerated grain growth and particles agglomeration of the combustion product, and the optimal temperature was 300 °C.

Optimization of sol–gel combustion synthesis of calcium looping CO2 sorbents, Part Ⅱ: Effects of thermal activation conditions

This work is the extension of part Ⅰ. The last procedure in the technical route of sol–gel combustion synthesis for CaO sorbents preparation, i.e. the thermal activation process was studied. The effects of the relevant preparation parameters including temperature, duration, and heating rate on the cyclic CO2 sorption performance, micromorphology, pore size distribution, and physical parameters of the prepared pure CaO sorbents were investigated. Results were obtained that high temperature (>950 ℃), long duration (>1 h), and low heating rate (<2 ℃/min) in the thermal activation process accelerated the formation of a stable structure in CaO sorbents. Accordingly, the sorbent showed low initial conversion, an opposite increasing trend in the first several cycles, and high cyclic stability. The optimal thermal activation condition was 850 ℃ for 5 min without heating rate. Furthermore, by integrating the optimization results of the whole technical route, the optimal CaO sorbent was prepared, which showed excellent performance. With the cyclic condition of 10 minutes of carbonation at 650 ℃ under 15% volume CO2 and 10 minutes of calcination at 850 ℃ under 100% volume N2, its carbonation conversion varied from 98.2% to 52.1% through 50 cycles. An average enhancement of 21.8% in 50 cycles was obtained compared to the sorbent before optimization and the average enhancement was 168.3% compared to CaCO3. Moreover, the pH value of the precursor solution was the most influential factor among the preparation variables.

Synthesis of pure phase SmFeO3 orthoferrites via self-propagating sol-gel combustion synthesis and study of Ce doping effect on their ferroelectric properties

SmFeO3 (SFO) is a highly challenging rear earth orthoferrites system for future modern spintronics applications and data storage devices due to its outstanding dielectric and ferroelectric properties, among other RFeO3 members. In the present attempt, Ce doped SFO system with compositions Sm1-xCexFeO3 (where x = 0.02 to 1) is explored to reveal its structural and ferroelectrics behavior in view to check its suitability for data storage applications. The systems were synthesized by a sol-gel method based on glycine gel reaction. The structural features of the as-synthesized samples are fitted by Rietveld refinement of x-ray diffraction patterns, which confirms an orthorhombic phase with pbnm space group. Temperature driven ferroelectric properties of Sm1-xCexFeO3 (where x = 0.02 to 1) were studied. Ce doped SmFeO3 indicates a reduction in losses and leakage current by Ce doping, suggesting that it is a promising material to explore as room temperature multiferroics.

Magnetic properties of mesoporous hematite/alumina nanocomposite and evaluation for biomedical applications

A porous hematite/alumina nanocomposite is produced by sol-gel combustion synthesis. The XRPD, Raman and FTIR methods show the presence of α-Fe2O3 phase while SEM, TEM, EDS and BET techniques further reveal the formation of porous ellipsoid-like nanostructure of hematite nanoparticles coated by amorphous alumina. Hematite nanoparticles have a size of ~40 nm whereas the porous hematite/alumina nanocomposite particles are ~100 nm in size with characteristic pores of ~7 nm. The M(H) at 300 K exhibits coercivity HC = 293 Oe and magnetization MS = 2.71 emu/g and at 5 K HC = 1150 Oe and MS = 9.25 emu/g. The M(T) under H = 100 Oe shows a bifurcation between ZFC/FC magnetization curves at all measurement temperatures Tirr>350 K (irreversibility temperature) and blocking temperature at TB ~ 305 K. Unexpectedly, the M(T) measurements under H = 10 kOe reveal the suppressed Morin transition at TM = 225 K. The analysis of the results and data from the literature reveal that the porous surface structure of hematite induces the atypical magnetic properties. A magnetic resonance imaging (MRI) properties show the transverse relaxivity rate (r2) of 0.44 mM−1s−1 at 7 T and 1.06 mM−1s−1 at 15.2 T. The investigated nanocomposite particles could be useful in biomedical applications due to their low cytotoxicity and porous nanostructure.

Sol-Gel Combustion Synthesis, Crystal Structure and Luminescence of Cr3+ and Mn4+ Ions in Nanocrystalline SrAl4O7

A series of strontium dialuminate SrAl4O7 nanopowders with the grossite-type structure doped with chromium and manganese ions were synthesized by the combined sol–gel solution combustion method with use of two different strontium salts. The Cr3+ and Mn4+ ions concentrations were varied from 0.05 to 5 at.%. Evolution of phase composition, crystal structure, and microstructural parameters of the nanocrystalline materials depending on the synthesis conditions, temperature of thermal treatment, and dopant content were investigated by the X-ray powder diffraction and the scanning electron microscopy techniques. Photoluminescent properties of SrAl4O7 nanophosphors activated with Cr3+ and Mn4+ ions were studied at room temperature. The samples exhibit typical photoluminescence in the deep-red spectral region, corresponding to d-d transitions in Cr3+ or Mn4+ ions. The intensity of this deep-red emission is dependent on the dopant concentration and annealing temperature. Features of the formation of octahedral surroundings around Cr3+ or Mn4+ ions are discussed.

Electromagnetic wave absorption properties of Pr1-xBaxMnO3 ceramics prepared by a sol–gel combustion method

Manganese-based rare-earth perovskite oxides with excellent dielectric loss and effective magnetic loss have attracted considerable attention as microwave-absorbing materials. Herein, irregular spherical particles of Pr1-xBaxMnO3 (x = 0, 0.02, 0.04, 0.06) were successfully designed and fabricated by a sol–gel combustion method. The Ba2+ doping amount played a dominant role in adjusting the electromagnetic (EM) functions of the PrMnO3 ceramics. X-ray diffraction and refinement results illustrated that Ba2+ doping had no effect on the main phase of PrMnO3, but it caused lattice distortion and led to changes in the lattice constant of the material. The magnetisation curves did not reach saturation, and the materials had low coercivity at room temperature. Fluctuations in the Mn4+/Mn3+ ratio due to oxygen vacancies decreased owing to the addition of Ba2+, as demonstrated by the X-ray photoelectron spectroscopy analysis. It was observed that the absorption of electromagnetic wave (EMW) energy could be effectively controlled by adjusting the Ba2+ content. The Pr0.98Ba0.02MnO3 sample exhibited the best EMW absorption ability; the minimum reflection loss (RLmin) was -46.45 dB (absorption rate of 99.99%), and the matching thickness was 3.7 mm. The maximum bandwidth of the Pr0.98Ba0.02MnO3 sample was 6.16 GHz, while the thickness of the absorbing coating was only 2.5 mm. When d = 5.5 mm, Pr0.94Ba0.06MnO3 achieved an RL of -18.97 dB at 5.04 GHz (C band). This shows that Pr0.94Ba0.06MnO3 also has good microwave absorption ability in the low-frequency C band, and its RL peak conformed to the nλ/4 cancellation law at a given thickness. The results show that the low-cost sol–gel combustion synthesis process and lightweight, wideband, and strong absorption ability of Pr1-xBaxMnO3 make it a promising candidate for microwave absorbers.

Sol-gel combustion synthesis of merwinite and its biomedical applications

The multidisciplinary attribute of biomaterials requires scientists to contrive and concoct the material, engineers to design and fabricate the prosthesis, and physicians to swot the response of natural tissues on artificial biomaterials implanted in the body. In this present experiment, energy efficient sol–gel combustion method has been adopted for the preparation of merwinite using citric acid as a reducing agent. Nitric acid played dual role as catalyst and oxidizer during gelation and combustion respectively. The XRD analysis confirmed that single phasic merwinite phase formation was achieved at 1000 °C without any secondary phase impurities. The bioactivity investigation of merwinite showed the deposition of hydroxyapatite on day three itself over the surface of the immersed scaffold in the physiological medium.

Evaluating the Activity and Stability of Perovskite LaMO3-Based Pt Catalysts in the Aqueous Phase Reforming of Glycerol

The aqueous phase reforming of glycerol, to hydrogen, alkanes and liquid phase dehydration/dehydrogenation products, was studied over a series of 1 wt% Pt/LaMO3 (where M = Al, Cr, Mn, Fe, Co, Ni) catalysts and compared to a standard 1 wt% Pt/γ-Al2O3 catalyst. The sol–gel combustion synthesis of lanthanum-based perovskites LaMO3 produced pure phase perovskites with surface areas of 8–18 m2g−1. Glycerol conversions were higher than the Pt/γ-Al2O3 (10%) for several perovskite supported catalysts, with the highest being for Pt/LaNiO3 (19%). Perovskite-based catalysts showed reduced alkane formation and significantly increased lactic acid formation compared to the standard catalyst. However, most of the perovskite materials undergo phase separation to LaCO3OH and respective M site oxides with Pt particle migration. The exception being the LaCrO3 support which was found to remain structurally stable. Catalytic performance remained stable over several cycles, for catalysts M = Al, Cr and Ni, despite phase separation of some of these materials. Materials where M site leaching into solution was observed (M = Mn and Co), were found to be catalytically unstable, which was hypothesised to be due to significant loss in support surface area and uncontrolled migration of Pt to the remaining support surface. In the case of Pt/LaNiO3 alloying between the exsoluted Ni and Pt was observed post reaction.

Influence of fuels in the sol-gel combustion synthesis of Li2MnO3 positive electrode material for Li-ion battery

The capacities of Li2MnO3 depend on the method of synthesis and synthesis conditions. The influence of the nature of fuel and fuel compositions on the sol-gel combustion synthesis (SCS) of Li2MnO3 and the concomitant effect on their electrochemical performance are reported. The use of glycine, citric acid fuels and their mixtures in the fuel stoichiometric compositions resulted in a violent reaction leading to loss of powders. Therefore, the fuel-rich (FR) composition that allows for better complexation of the metals in solution and doesn't result in any violent reaction is recommended in the SCS of Li2MnO3 and other ceramic oxides. The glycine FR composition produced Li2MnO3 with the poorest electrochemical performance that was ascribed to its rough morphology. The citric acid FR Li2MnO3 sample (C-FR) delivered the most comprehensive electrochemical performance considering its increasing discharge capacities with an increase in the current density, its suppression of the charge transfer resistance after the rate capability test, and good rate performance. The improved electrochemical performances of C-FR were attributed mainly to its large particle size and well-developed crystallites. The results show that the SCS of C-FR Li2MnO3 sample could be further optimized to exploit better electrochemical properties of this material.

Sol-gel combustion synthesis and characterization of CoCr2O4 ceramic powder used as color solar absorber pigment

A facile citric acid assisted sol-gel combustion method was performed to synthesize cobalt chromite (CoCr2O4) ceramic pigment. The effect of the annealing temperature on structure, morphologies, and optical properties of the prepared CoCr2O4 pigments were systematically studied by thermogravimetry, differential thermal analysis, X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM). The results show that CoCr2O4 spinel crystal was achieved after heat treatment of the as-burnt powder at a relatively low temperature (400 °C) and the average crystallite size of the CoCr2O4 pigment increased with the annealing temperature. Furthermore, on the CIE parameters of CoCr2O4 pigment, a* and b* values became much more negative with the annealing temperature due to much more Co2+ ions located in tetrahedral sites and much more Cr3+ ions located in octahedral sites. Finally, the measured solar absorptance indicates that this ceramic pigment is expected to fabricate the color paint coating for solar absorber application.

Evaluation of the Microstructure and the Electrochemical Properties of Ce0.8(1−x)Gd0.2(1−x)CuxO[1.9(1−x)+x] Electrolytes for IT-SOFCs

The influence of copper addition (0.5–2 mol%) on the crystal structure, densification microstructure, and electrochemical properties of Ce0.8Gd0.2O1.9 synthesized in a one-step sol–gel combustion synthesis route has been studied. It has been found that Cu is very active as sintering aids, with a significative reduction of GDC firing temperature. A reduction of 500 °C with a small amount of copper (0.5 mol%) was observed achieving dense bodies with considerable ionic conductivities. Rietveld refined was used to investigate the crystal structure while relative density and microstructural examination were performed in the sintering temperature range of 1000–1200 °C after dilatometer analysis. High dense bodies were fabricated at the lowest sintering temperature, which promotes the formation of Ce0.8(1−x)Gd0.2(1−x)CuxO[1.9(1−x)+x] solid solution and the absence of secondary phase Cu-rich or the segregation or copper at the grain boundary. As compared to the pure GDC an improvement of total conductivity was achieved with a maximum for the highest copper content of 2.23·10−3–9.19·10−2 S cm−1 in the temperature range of 200–800 °C.