2025 - Publications Repository - Gdańsk University of Technology

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Surface Charge Density Spectra: Complex Analysis of the Electrical Double Layer Developed from Measurements of Hexanol Adsorption Kinetics
- Kazimierz Darowicki
- Anna Karólkowska
- Szymon Wysmułek
2025 Journal of Physical Chemistry C
A procedure for deriving surface charge density spectra from differential capacitance data is presented in this study, providing a deeper analysis of the generated charge. A set of simulated differential capacitance spectra was determined for three types of adsorption process control: diffusion control, adsorption control, and mixed control. Based on the differential capacitance curves and spectra, surface charge density spectra were determined. Shapes characteristic of the three types of control of the adsorption process were identified. Using the Dynamic Electrochemical Impedance Spectroscopy (DEIS) technique, the kinetics of hexanol adsorption on a mercury electrode was analyzed. A change in the controlling step of the hexanol adsorption process from diffusion control to adsorption control was observed, based on the relaxation time values and differential capacitance spectra shape. Using a procedure developed on the basis of simulated data, the surface charge density spectra were determined over the entire range of investigated potentials. The developed procedure enabled the separation of the electric double layer (EDL) capacitance from the adsorption pseudocapacitance over a wide potential range. The charges associated with the EDL and generated by increasing pseudocapacitance were determined. The contribution of both charges to the total charge generated with a change in electrode potential varied with the electrode potential.
Sustainability, reliability, and durability of civil engineering structures
- Agnieszka Tomaszewska
- Jacek Szafran
- Bettina Brune
- Krzysztof Wilde
2025 Full text Bulletin of the Polish Academy of Sciences-Technical Sciences
Considering the Bulletin Readers’ interest in civil engineering,the Special Section “Sustainability, reliability, and durability of civil engineering structures” is now presented, with papers that, by studying specific cases, fully embrace all aspects related to the topic, starting from geometry design, determination of load acting on a structure, characteristics of the material for construction purpose, characteristics of structural behaviour under a certain load, identification of structural parameters or model, safety assessment, and finally, comfort of use. Most of the papers included in this Special Section were orally presented during the 29th International Conference “Lightweight Structures in Civil Engineering”, held in December 2023 at the Gdansk University of Technology.
Tailoring oxide nanoparticle exsolution in La0.5Ba0.5-yCo1-xFexO3-δ
- Daria Balcerzak
- Andrés López-García
- Alfonso Carrillo
- Maria Balaguer
- Jose M. Serra
- Truls Norby
- Ragnar Strandbakke
- Maria Gazda
- Sebastian Wachowski
2025 JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
We show that oxide nanoparticles (NPs) exsolve on La0.5Ba0.5-yCo1-xFexO3-δ (x = 0-1, y = 0 or 0.01) in oxidizing conditions. The phenomenon occurs only in Co-containing materials and depends on pO2 and pH2O pressures. Under dry conditions, the smallest NPs average about 30 nm, with 200-300 NPs/µm2 at pO2=5×10-5 atm. For pO2=1 atm, NP size increases to 100-200 nm, and population drops to a few to about 20 NPs/µm2 depending on A-site nonstoichiometry and x. In humid conditions, the smallest NPs around 50 nm, with a peak of 100 NPs/µm2 exsolve for pO2=1. Transmission electron microscopy shows that exsolved NPs in La0.5Ba0.5-yCoO3-δ are Ba-O-rich. We propose defect chemistry models, indicating that exsolution is driven by oxidation reactions forming A-site vacancies, increasing exsolved material with higher pO2. We suggest that adsorbed water under humid conditions blocks nucleation sites, altering observed trends.
Technological Considerations of Periodic Repair Works of Concrete Industrial Floors
- Sylwia Świątek-Żołyńska
- Maciej Niedostatkiewicz
2025 Full text Civil and Environmental Engineering Reports
Concrete floors are among the elements in construction facilities whose design requires engineering experience, workmanship requires the maintenance of a technological regime, while during their operation it is necessary to conduct periodic repairs. Concrete floors are most often used as working and communication space in industrial facilities, and very often they are also a functional element in objects that are immovable monuments. Regardless of the place of installation, concrete floors require periodic maintenance works whose scope should each time be individually adapted to the current use of the object. Improper selection of maintenance work technology and incorrect application of technological solutions related to the renovation of floors can cause rapid deterioration of their technical condition, which may lead to the need to take them out of service, which in turn may result in the need to interrupt the use of the building facility, including production facilities of industrial facilities. The paper presents a collection of practical information related to conducting periodic repair work on concrete industrial floors The article is a case study and addresses specific situations related to the loss of serviceability of concrete industrial floors.
Text analytics for co-creation in public sector organizations: a literature review-based research framework
- Nina Rizun
- Aleksandra Revina
- Noella Edelmann
2025 Full text ARTIFICIAL INTELLIGENCE REVIEW
The public sector faces considerable challenges that stem from increasing external and internal demands, the need for diverse and complex services, and citizens’ lack of satisfaction and trust in public sector organisations (PSOs). An alternative to traditional public service delivery is the co-creation of public services. Data analytics has been fueled by the availability of immense amounts of data, including textual data, and techniques to analyze data, so it has immense potential to foster data-driven solutions for the public sector. In the paper, we systematically review the existing literature on the application of Text Analytics (TA) techniques on textual data that can support public service co-creation. In this review, we identify the TA techniques, the public services and the co-creation phase they support, as well as envisioned public values for the stakeholder groups. On the basis of the analysis, we develop a Research Framework that helps to structure the TA-enabled co-creation process in PSOs, increases awareness among public sector organizations and stakeholders on the significant potential of TA in creating value, and provides scholars with some avenues for further research.
The Impact of 8- and 4-Bit Quantization on the Accuracy and Silicon Area Footprint of Tiny Neural Networks
- Paweł Tumialis
- Marcel Skierkowski
- Jakub Przychodny
- Paweł Obszarski
2025 Electronics
In the field of embedded and edge devices, efforts have been made to make deep neural network models smaller due to the limited size of the available memory and the low computational efficiency. Typical model footprints are under 100 KB. However, for some applications, models of this size are too large. In low-voltage sensors, signals must be processed, classified or predicted with an order of magnitude smaller memory. Model downsizing can be performed by limiting the number of model parameters or quantizing their weights. These types of operations have a negative impact on the accuracy of the deep network. This study tested the effect of model downscaling techniques on accuracy. The main idea was to reduce neural network models to 3 k parameters or less. Tests were conducted on three different neural network architectures in the context of three separate research problems, modeling real tasks for small networks. The impact of the reduction in the accuracy of the network depends mainly on its initial size. For a network reduced from 40 k parameters, a decrease in accuracy of 16 percentage points was achieved, and for a network with 20 k parameters, a decrease of 8 points was achieved. To obtain the best results, knowledge distillation and quantization-aware training methods were used for training. Thanks to this, the accuracy of the 4-bit networks did not differ significantly from the 8-bit ones and their results were approximately four percentage points worse than those of the full precision networks. For the fully connected network, synthesis to ASIC (application-specific integrated circuit) was also performed to demonstrate the reduction in the silicon area occupied by the model. The 4-bit quantization limits the silicon area footprint by 90%.
The impact of China’s One-Belt One-Road initiative on international trade and global value chains
- Yuxin Lu
- Joanna Wolszczak-Derlacz
2025 Asia-Pacific Journal of Accounting & Economics
This study examines the potential effects of China’s ‘One-Belt One-Road’initiative (OBOR) on trade flows and global value chain (GVC) connections.The empirical analysis is based on the augmented trade gravity model, which comprises 186 economies and 199 of their partners from 2000 to 2018. We also estimate the gravity model for involvement in GVC (domestic value added in intermediate exports, foreign value added in exports, and one country’s contributed value in another’s total exports). OBOR proves to be positively correlated with international trade and GVC, while some corridors seem to benefit more than others (e.g. China-Pakistan,China-Mongolia-Russian Federation, and Bangladesh-China-India-Myanmar).
The impact of goat hair as a natural animal fiber on properties of the lightweight cement composite
- Najmeh Hassas
- Farzam Omidi Moaf
- Marzena Kurpińska
- Teresa Bardzińska-Bonenberg
- Justyna Borucka
- Hakim S. Abdelgader
- Rohan Soman
- Mikołaj Miśkiewicz
2025 Scientific Reports
The increasing demand for sustainable and eco-friendly construction materials has prompted the exploration of natural fibers as reinforcement in cement composites. This study investigates the potential of goat hair as a natural fiber reinforcement in lightweight cement composites to enhance mechanical properties and sustainability. The research evaluates goat-hair-reinforced composites’ flexural and compressive strengths at 7 and 28 days after mixing. The results show that the inclusion of goat hair at a rate of 0.4% of cement, as a reinforcing material, leads to a significant increase in flexural and compressive strength. Specifically, flexural strength increased by 2.5% and 21.8%, while compressive strength improved by 5.5% and 21.5% at water-to-cement ratios of 0.4 and 0.5, respectively, compared to the control mixture. The findings demonstrate the effectiveness of goat hair in improving mechanical performance while reducing the environmental footprint of construction materials. This study highlights the need for further exploration of natural fibers in sustainable construction practices, focusing on optimizing mechanical performance and eco-friendly materials for broader applications.
The influence of brace to chord rotational connection stiffness on stability of the truss
- Marcin Krajewski
2025 Bulletin of the Polish Academy of Sciences-Technical Sciences
The paper is devoted to the numerical analysis of the roof truss subjected to upward wind loading and braced at the tensioned top chord. The linear buckling analysis were performed for the beam and shell model of the structure. As the result the influence of rotational connection stiffness between the brace and the top chord on the truss stability was appointed. The biaxial strength testing machine was used to conduct the experimental tests of the rotational connection stiffness between selected steel profiles. The results in the form of measured structural displacements and rotations were presented. The static nonlinear analysis results performed for the shell model of the structural connection were compared to the results obtained on the experimental set-up.
The influence of chitosan's molecular weight, concentration, and dissolution method on the properties of electrophoretically deposited coatings on the Ti13Nb13Zr alloy surface
- Łukasz Pawłowski
- Szymon Mania
- Adrianna Banach-Kopeć
- Karol Staszczyk
- Aleksandra Mirowska
- Aleksandra Mielewczyk-Gryń
- Robert Tylingo
2025 MATERIALS CHEMISTRY AND PHYSICS
In this study, the effects of molecular weight (high, medium, and low), concentration (0.1 and 0.5 %) and dissolution method (in a rarely used hydroxyacetic acid and utilizing a novel CO2 saturation) of chitosan on the microstructure, chemical composition, wettability, surface roughness, adhesion, corrosion resistance and antibacterial activity of chitosan coatings electrophoretically deposited (10 V, 1 min) on β titanium alloy Ti13Nb13Zr were investigated. Microstructural analysis showed that low molecular weight chitosan at low concentrations formed uniform coatings while increasing these parameters resulted in uneven coatings with agglomerates. Energy-dispersive X-ray and Fourier transform infrared spectroscopy analyses confirmed the presence of chitosan on all coated samples. Higher concentrations of chitosan yielded thicker coatings. Wettability tests confirmed hydrophilic properties for all samples, with contact angles around 70°. Surface roughness varied with chitosan concentration, showing increased roughness for higher concentrations. Adhesion tests showed the highest critical load for high molecular weight chitosan coatings with a concentration of 0.1 %. Corrosion tests revealed that low molecular weight chitosan coatings provided the best protection. Antimicrobial assays showed that chitosan coatings prepared using acid dissolution had strong bactericidal activity against both Gram-positive and Gram-negative bacteria, while those prepared using CO2 saturation showed limited bacteriostatic activity. These findings suggest that chitosan coatings, especially those prepared using acid dissolution, hold promise for biomedical applications requiring corrosion resistance and antibacterial properties.
The influence of selected metal oxides and laser modification on the surfaces of titanium alloys – Bibliometric and systematic review
- Dominika Kwidzińska
- Magdalena Jażdżewska
- Dariusz Fydrych
2025 OPTICS AND LASER TECHNOLOGY
Manufacturing of oxide coatings (ZnO, ZrO2 , CuO) and laser processing are methods for modifying the surface of titanium and its alloys. It is particularly useful in implantology, where these techniques allow for proper connection of the implant to human tissue. The article consists of two complementary parts: a bibliographic review and a literature survey. The results of a bibliographic analysis conducted for a set of 429 publications indexed in the Web of Science (WOS) database regarding laser treatment of titanium and its alloys were pre sented. Using WOS, VOSviewer and Biblioshiny tools a comprehensive view of the development and dynamics of changes in the considered topics was determined and summarized. The most frequently discussed topics are aimed at determining structure–property relationships (microstructure, mechanical properties and corrosion resistance). The most active research centers and teams (from China, Poland, Germany, France) and journals (Surface Coatings Technology, Applied Surface Science, Materials) and the relationship between them are demonstrated. A systematic review of the literature shows that the surface properties of titanium are influenced by both the selected oxide and the method used to coat its surface. Literature analysis also indicated that a promising direction of research is to generate the synergy effect through processes using different surface modification methods. The ultimate goal of the article is not only the determination of gaps in the state of knowledge but also the identification of gaps requiring special research attention in future scientific works.
The Laser Processing of the Stainless-Steel Surface Layer of a Heat Exchanger Membrane in Order to Enhance Its Heat Transfer Coefficient
- Ewa Kozłowska
- Marek Szkodo
- Tomasz Muszyński
- Paulina Adamska
2025 Coatings
Research on temperature regulation is essential for ensuring thermal comfort and optimizing machine performance. Effective cooling systems are critical in industrial processes and everyday electronic devices in order to prevent overheating. Laser-modified heat exchangers can enhance heat dissipation without increasing weight, addressing the need for energy-efficient solutions in the market. The main aim of this experimental research was to establish an efficient method for altering the surface layer of AISI 316L stainless steel with laser pulses and to determine the effectiveness of the laser alterations to the surface layer in the context of intensifying the convective heat transfer. A series of laser-texturing processes was performed on the surface layer of AISI 316L steel using a Nd: YAG pulse laser. Selected samples were subjected to a series of measurements using a recuperator-type heat exchanger. Based on the measurements’ results, the heat transfer coefficients, α, obtained from the modified surfaces were determined. The results were compared with other data from the existing literature and those obtained from unmodified reference samples. The intensification of the convective heat transfer was achieved for 43% of the modifications conducted with a pulsed laser. The highest observed average increase in the heat transfer coefficient, α, was 16.53%. However, the effective intensification of the convective heat transfer, in some cases, was only observed for a certain range of temperatures or flow dynamics parameters.
The role of nanomaterials in tailoring electromembrane extraction performance: A review
- Wajid Ali Khan
- Muhammad Balal Arain
- Stig Pedersen-Bjergaard
- Hameed Ul Haq
- Roberto Castro Munoz
- Grzegorz Boczkaj
2025 TALANTA.The International Journal of Pure and Applied Analytical Chemistry
Electromembrane extraction (EME) is a membrane-based miniaturized microextraction technique used to extract ionized analytes from complex mixtures. EME extracts can be analyzed using all major analytical instrumental techniques. The major advantages of EME include short extraction time, low consumption of organic solvents and chemicals, high extraction capability, high selectivity, and efficient sample cleanup. Numerous modifications to EME, such as the use of microfluidic devices, green solvents, biobased renewable membranes, and hyphenation with other separation techniques, have increased the selectivity and sensitivity of EME. Furthermore, nanomaterials have been used to improve the efficiency, selectivity, and stability of EME systems. Various nanomaterials have been proposed for the modification of EME-based separation systems. The larger surface area, high porosity, and various interactions with the target analytes are the most important properties of nanomaterials and nanocomposites in improving the figures of merit of EME. Nanomaterials have mainly been used to modify the chemical composition of the liquid membrane in EME, but modifications of the polymeric support membrane and the electrodes have also been reported. Therefore, this review highlights the transformative role of nanomaterials in EME, focusing on their application in enhancing extraction efficiency, selectivity, and stability. Key advancements include modifying supported liquid membranes (SLMs), membrane decoration, and optimizing electrode performance. The review also critically examines challenges, such as pore blockage and electrolysis-induced instability, offering insights into future directions for nanomaterial-enhanced EME. Despite of the numerous benefits of nanomaterials, their environmental toxicity cannot be overlooked and should be carefully examined for each new case. A bio-based and biopolymer-based nanomaterials in future EME studies can significantly address these issues while remaining aligned with green chemistry principles. Artificial intelligence-based models should be applied to predict effective nanomaterials in EME, thus significantly reduce chemical costs and consumption while also increasing the greenness level of developed EME approaches. Finally, long-term stability of new developed solutions should be an obligatory part of each new research in this field.
The solvent-assisted dispersive solid-phase extraction method revisited. Application for the determination of anionic surfactants
- Serhii Zaruba
- Patrycja Makoś-Chełstowska
- Vasil Andruch
2025 Advances in Sample Preparation
A new approach in solvent-assisted dispersive solid-phase extraction (SA-DSPE) procedure using a supercooled liquid was developed. It demonstrates the first use of a supercooled liquid in this technique, in particular, and in chemical analysis in general. Moreover, to the best of our knowledge, this is the first work devoted to the determination of the total concentration of anionic surfactants (as LAS, Linear alkylbenzene sulfonate) using a micro-SPE technique. The method is based on the formation of an ion pair between astraphloxine (cationic dye) and an anionic surfactants, with subsequent extraction of the ion pair formed onto a benzophenone sorbent generated in situ after injection of its 5 % solution in an acetone:water 80:20 v/v mixture into an aqueous sample. The resulting turbidness was sedimented by centrifugation. The addition of a few crystals of benzophenone then leads to the solidification of a supercooled solution of the sorbent, which facilitates the separation. Afterwards, the bulk of the aqueous phase was easily decanted, and the resulting sediment was dissolved with 500 μL of acetone; absorbance measurements were carried out in a semi-microcuvette. The calibration plot was linear up to 0.5 µmol L−1 of sodium dodecylbenzene sulfonate (SDBS). The LOD and LOQ, were 9.0 and 30 nmol L-1 of SDBS, respectively. The developed procedure was applied for the determination of anionic surfactants in various real water samples.
The strategies of nutrient removal compounds from wastewater by using aquatic plants in the Green deal implementation
- Larysa Sablii
- Veronika Zhukova
- Jakub Drewnowski
2025 Full text Desalination and Water Treatment
The aim of the study was to determine the efficiency of wastewater treatment from nitrogen compounds - ammonium, nitrite, nitrate, and phosphate - using Lemna minor and Spirogyra sp. in the context of the strategies toward Green Deal Implementation. Meanwhile, the various biological treatment methods of nutrients according to the value-added and application prospects were also discussed as a future solution in the Circular Economy Model. The complementary effect of Lemna minor and other higher aquatic plants, in particular Spirogyra sp. was established. The efficiency of nitrate removal for 7 days was 86.4 %, andphosphate removal was 78 %. The concentration of NO3 - ions after treatment was 6.8 mg/dm3, and phosphate (P2O5) 2.2 mg/dm3. It was noted that the simultaneous use of an increased dose of duckweed Lemna minor and the algae Spirogyra sp. significantly increases the efficiency of nitrate removal from the experimental samples, and the efficiency of phosphate removal did not change compared to the experiment without the use of the algae Spirogyra sp. and with the use of a double dose of duckweed. Under these conditions, the nitrate removal efficiency for a duration of 7 days was 92 % and the phosphate removal efficiency was 80 %. The concentration of NO3 - ions after treatment was 4 mg/ dm3, and phosphate (P2O5) 2 mg/dm3.
The tensile strength of different methods of anterior cruciate ligament graft end stitches in an animal model
- Marcin Dembski
- Patryk Kawa
- Jakub Tarnawski
- Marcin Ceynowa
- Krzysztof Żerdzicki
- Paweł Kłosowski
2025 KNEE
Background: There are several methods for stitching graft ends in anterior cruciate liga-ment reconstructive surgery. The tendon-suture construct should be able to withstand ten-sioning until the graft is stabilized with an implant. Methods: In this biomechanical study, 40 porcine lower extremity tendons ends were stitched with No. 2 suture, secured to the grips of the Zwick-Roell testing machine and tested for load at failure and type of failure (tendon v/s suture thread). The applied force was linear, the results are given in Newtons (N) as a mean. The Mann-Whitney U test was used for statistical analysis. The following constructs were compared: a whipstitch of each tendon end individually with 3, 4, and 5 passes through the tendon, a whipstitch of both tendon ends folded together and a tendon end knot without stitching. Results: All specimens survived the minimum tensile load of 80 N. The load at failure for whipstitch with 3,4 and 5 passes were 175 N, 211 N and 254 N respectively. The load at failure was greater for individual whipstitch than for both ends folded together (261 N v/s 152 N). The mean load at failure for braided graft was 209 N. The braided graft slips off the tendon before failure leading to uneven strength distribution during tensioning. Conclusion: Increasing number of suture passes resulted in higher load at failure. Individual tendon ends whipstitched with 5 passes was the strongest construct. All of the investigated techniques are sufficient to withstand the suggested optimal graft tension of 80 N.
Theoretical design of nanocatalysts based on (Fe2O3)n clusters for hydrogen production from ammonia
- Sapajan Ibragimov
- Andrey Lyalin
- Sonu Kumar
- Yuriko Ono
- Tetsuya Taketsugu
- Maciej Bobrowski
2025 Full text JOURNAL OF CHEMICAL PHYSICS
The catalytic activities of high-spin small Fe(III) oxides have been investigated for efficient hydrogen production through ammonia decomposition, using the artificial force induced reaction method within the framework of density functional theory with the B3LYP hybrid exchange–correlation functional. Our results reveal that the adsorption free energy of NH3 on (Fe2O3 )n (n = 1–4) decreases with increasing cluster size up to n = 3, followed by a slight increase at n = 4. The strongest NH3 adsorption energy, 28.55 kcal/mol, was found for Fe2O3 , where NH3 interacts with a two-coordinated Fe site, forming an Fe–N bond with a length of 2.11 Å. A comparative analysis of NH3 dehydrogenation and H2 formation on various Fe(III) oxide sizes identifies the rate-determining steps for each reaction. We found that the rate-determining step for the full NH3 dehydrogenation on (Fe2 O3 )n (n = 1–4) is size-dependent, with the NH* → N* + H* reaction acting as the limiting step for n = 1–3. In addition, our findings indicate that H2 formation is favored following the partial decomposition of NH3 on Fe(III) oxides.
Thermal affection on hydrogen diffusion in different structures of nickel alloy
- Pasquale Cavaliere
- Behzad Sadeghi
- Chen Zhenghan
- Alicja Stanisławska
2025 Multidiscipline Modeling in Materials and Structures
Purpose Based on previous research, we choose nickel alloy 718 as the research material and use finite element analysis (FEA) to simulate the hydrogen diffusion in lattice, grain, boundary grain and dislocation in different thermal loads, aiming to understand the intricate mechanisms underlying hydrogen diffusion in nickel-based alloys, which will contribute to driving progress in the field of hydrogen diffusion for understanding and management HE. Design/methodology/approach In this research, we focus on nickel alloy 718, creating a numerical model with traps to simulate the hydrogen diffusion in lattice, grain, boundary grain and dislocation with different thermal loads, by FEA. Findings The results demonstrated that traps improve the hydrogen saturation in materials, and because of thermal saturation and heat flux, higher temperatures decrease the hydrogen solubility and increase hydrogen diffusion velocity, which can decrease hydrogen saturation. Originality/value Based on our previous research and publications, we developed a finite element model to define the hydrogen trapping in different microstructural features of nickel-based superalloys. The model is very complex with a very large number of elements capable of obtaining very affordable results.
Thermoelectric and electrical properties of triple-conducting multicomponent oxides based on substituted barium cerate-zirconate
- Martyna Czudec
- Daniel Jaworski
- Jagoda Budnik
- Aleksandra Mielewczyk-Gryń
- Tamilarasan Subramani
- Maria Gazda
- Alexandra Navrotsky
- Tadeusz Miruszewski
2025 Full text DALTON TRANSACTIONS
Multicomponent oxides often have exceptional thermal stability and interesting electronic properties. The present work presents the thermoelectric and electrical properties of the Ba(Zr0.2Hf0.2Sn0.2Ti0.2Fe0.2)O3−δ and Ba(Zr0.1Hf0.1Sn0.1Ti0.1Co0.1Ce0.1Bi0.1Fe0.1Y0.1Zn0.1)O3−δ multicomponent perovskites. Single-phase cubic perovskites were synthesized using the solid-state reaction method. They were characterized using X-ray diffraction, drop-solution calorimetry, and thermogravimetry methods. The total electrical conduc tivity and Seebeck coefficient measurements were performed in dry and wet air at temperatures between 600 and 1050 K. It was found that Ba(Zr0.1Hf0.1Sn0.1Ti0.1Co0.1Ce0.1Bi0.1Fe0.1Y0.1Zn0.1)O3−δ is thermo dynamically less stable than Ba(Zr0.2Hf0.2Sn0.2Ti0.2Fe0.2)O3−δ. Moreover, this oxide incorporates a higher amount of water and exhibits higher conductivity and lower Seebeck coefficient. Charge transport in both perovskites can be assigned to the small-polaron hopping process via electron holes. An interesting temperature dependence of the Seebeck coefficient was found and, at temperatures above 750 K, related to hopping between energetically inequivalent states
Thermoelectric and electrical transport properties of mixed-conducting multicomponent oxides based on Ba(Zr,Ce)O3-δ
- Konrad Kuc
- Martyna Czudec
- Daniel Jaworski
- Jagoda Budnik
- Aleksandra Mielewczyk-Gryń
- Maria Gazda
- Tadeusz Miruszewski
2025 JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
In this work, the chosen physicochemical properties of single-phase multicomponent oxides BaTi1/8Fe1/8Co1/8Y1/8Zr1/8Sn1/8Ce1/8Hf1/8O3-δ and BaTi1/9Fe1/9Co1/9Y1/9Zr1/9Sn1/9Ce1/9 Hf1/9Bi1/9O3-δ were studied. The microstructure of the compounds strongly depended on the presence of bismuth in the structure. The electrical transport studies showed a level of electrical conductivity of ∼10−3 - 10−2 S/cm in the temperature range 673–1073 K. Electrical conductivity was thermally activated and the dominant conduction mechanism was the hopping of small polarons. Moreover, total electrical conductivity changes in the dry and humidified atmosphere at lower temperatures due to the presence of protonic defects in the structure. Thermoelectric measurements showed a relatively high value of the Seebeck coefficient for studied ceramics. Its values ranged between 50 and 250 μV/K depending on the sample and temperature. The Seebeck coefficient sign was positive, meaning that electron holes and/or oxygen vacancies were predominant charge carriers in oxidizing atmospheres. Additionally, the Seebeck coefficient was found to be different in the humidified atmosphere which indicates an influence of protonic defects on thermoelectric transport. The obtained power factor Pf turned out to be low and dependent on the presence of protonic defects in the structure. This indicates, that the efficiency of the MOs-based operating thermoelectric generators can be controlled by changing the partial pressure of water vapor