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Gdańsk University of Technology

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Publications from the year 2021

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  • Testing of Software for the Planning of a Linear Object GNSS Measurement Campaign under Simulated Conditions
    • Sławomir Figiel
    • Cezary Specht
    • Marek Moszyński
    • Andrzej Stateczny
    • Mariusz Specht
    2021 Full text ENERGIES

    The precision of a linear object measurement using satellite techniques is determined by the number and the relative position of the visible satellites by the receiver. The status of the visible constellation is described by DOP. The obtained geometric coefficient values are dependent on many variables. When determining these values, field obstacles at the receiver location and satellite positions changing with time must be taken into account. Carrying out a series of surveys as part of a linear object GNSS measurement campaign requires the optimisation problem to be solved. The manner of the inspection vehicle’s movement should be determined in such a way that the surveys are taken only within the pre-defined time frames and that the geometric coefficient values obtained at subsequent points of the route are as low as possible. The purpose of this article is to develop a software for the planning of a linear object GNSS measurement campaign to implemented in motion and taking into account the terrain model and its coverage. Additionally, it was determined how much the developed program improves DOP values on the planned route under simulated conditions. This software has no equivalent elsewhere in the world, as the current solutions for the planning of a GNSS measurement campaign, e.g., Trimble GNSS Planning, GNSS Mission Planning, or GPS Navigation Toolbox, allow the satellite constellation geometry to be analysed exclusively for specific coordinates and at a specific time. Analysis of the obtained simulation test results indicates that the campaign implementation in accordance with the pre-determined schedule significantly improves the quality of the recorded GNSS data. This is particularly noticeable when determining the position using the GPS and GLONASS satellite constellations at the same time. During the tests conducted on the road along a three-kilometre-long route in Gdańsk, the average value of the obtained PDOP decreased by 22.17% thanks to using the software to plan a linear object GNSS measurement campaign. The largest drop in the geometric coefficient values was noted for an area characterised by a very large number of field obstacles. Under these conditions, the PDOP value decreased by approx. 25%. In areas characterised by a small number of field obstacles (single trees in the vicinity of the track, clusters of trees and buildings located along the track), the changes in the PDOP were slightly smaller and amounted to several percent.

  • Testing of the longest span soil-steel bridge in Europe – new quality in measurements
    • Mikołaj Miśkiewicz
    • Bartosz Sobczyk
    • Paweł Tysiąc
    2021

    The article describes interdisciplinary and comprehensive diagnostic tests of final bridge inspection and acceptance proposed for a soil – steel bridge made of corrugated sheets, being the European span length record holder (25.74 m). As an effect of an original concept a detailed and precise information about the structure response was collected. The load test design was based on the nonlinear numerical simulations performed by means of FEM. The in-situ measurements were done with aid of: inductive sensors, optical total station, terrestrial laser scanner. The results produced by terrestrial laser scanning were used to build a precise image of structure deformation in 3D space during the tests. The precision of laser mapping was additionally significantly increased by means of image tracing (vectorization) and calibration of results through parallel verification of the collected data with the values coming from optic total station and inductive sensors. Thus, new quality in measurements is introduced.

  • Testing Stability of Digital Filters Using Optimization Methods with Phase Analysis
    • Damian Trofimowicz
    • Tomasz Stefański
    2021 Full text ENERGIES

    In this paper, novel methods for the evaluation of digital-filter stability are investigated. The methods are based on phase analysis of a complex function in the characteristic equation of a digital filter. It allows for evaluating stability when a characteristic equation is not based on a polynomial. The operation of these methods relies on sampling the unit circle on the complex plane and extracting the phase quadrant of a function value for each sample. By calculating function-phase quadrants, regions in the immediate vicinity of unstable roots (i.e., zeros), called candidate regions, are determined. In these regions, both real and imaginary parts of complex-function values change signs. Then, the candidate regions are explored. When the sizes of the candidate regions are reduced below an assumed accuracy, then filter instability is verified with the use of discrete Cauchy’s argument principle. Three different algorithms of the unit-circle sampling are benchmarked, i.e., global complex roots and poles finding (GRPF) algorithm, multimodal genetic algorithm with phase analysis (MGA-WPA), and multimodal particle swarm optimization with phase analysis (MPSO-WPA). The algorithms are compared in four benchmarks for integer- and fractional-order digital filters and systems. Each algorithm demonstrates slightly different properties. GRPF is very fast and efficient; however, it requires an initial number of nodes large enough to detect all the roots. MPSO-WPA prevents missing roots due to the usage of stochastic space exploration by subsequent swarms. MGA-WPA converges very effectively by generating a small number of individuals and by limiting the final population size. The conducted research leads to the conclusion that stochastic methods such as MGA-WPA and MPSO-WPA are more likely to detect system instability, especially when they are run multiple times. If the computing time is not vitally important for a user, MPSO-WPA is the right choice, because it significantly prevents missing roots.

  • The adaptive spatio-temporal clustering method in classifying direct labor costs for the manufacturing industry
    • Mateusz Kalinowski
    • Jakub Baran
    • Paweł Weichbroth
    2021 Full text

    Employee productivity is critical to the profitability of not only the manufacturing industry. By capturing employee locations using recent advanced tracking devices, one can analyze and evaluate the time spent during a workday of each individual. However, over time, the quantity of the collected data becomes a burden, and decreases the capabilities of efficient classification of direct labor costs. However, the results obtained from performed experiments show that the existing clustering methods have failed to deliver satisfactory results by taking advantage of spatial data. In contrast to this, the adaptive spatio-temporal clustering (ASTC) method introduced in this paper utilizes both spatial and time data, as well as prior data concerning the position and working status of deployed machines inside a factory. The results show that our method outperforms the bucket of three well-known methods, namely DBSCAN, HDBSCAN and OPTICS. Moreover, in a series of experiments, we also validate the underlying assumptions and design of the ASTC method, as well as its efficiency and scalability. The application of the method can help manufacturing companies analyze and evaluate employees, including the productive times of day and most productive locations.

  • The added value of using the HEPA PAT for physical activity policy monitoring: a four-country comparison
    • Peter Gelius
    • Sven Messing
    • Sarah Forberger
    • Jeroen Lakerveld
    • Fiona Mansergh
    • Wanda Wendel-Vos
    • Joanna Żukowska
    • Catherine Woods
    2021 Full text Health Research Policy and Systems

    Background Public policy is increasingly recognized as an important component of physical activity promotion. This paper reports on the current status of physical activity policy development and implementation in four European countries based on the Health-Enhancing Physical Activity Policy Audit Tool (HEPA PAT) developed by WHO. It compares the findings to previous studies and discusses the general utility of this tool and its unique features in relation to other instruments. Methods The study was conducted as part of the Policy Evaluation Network (www.jpi-pen.eu) in Germany, Ireland, the Netherlands and Poland. Data collection built upon information obtained via the EU Physical Activity Monitoring Framework survey, additional desk research and expert opinion. Data analysis employed Howlett’s policy cycle framework to map and compare national physical activity policies in the four countries. Results In all countries under study, policy agenda-setting is influenced by prevalence data from national health monitoring systems, and the sport and/or health sector takes the lead in policy formulation. Key policy documents were located mainly in the health sector but also in sport, urban design and transport. Physical activity programmes implemented to meet policy objectives usually cover a broad range of target groups, but currently only a small selection of major policies are evaluated for effectiveness. National experts made several suggestions to other countries wishing to establish physical activity policies, e.g. regarding cross-sectoral support and coordination, comprehensive national action plans, and monitoring/surveillance. Conclusions This study provides a detailed overview of physical activity policies in the four countries. Results show that national governments are already very active in the field but that there is room for improvement in a number of areas, e.g. regarding the contribution of sectors beyond sport and health. Using the HEPA PAT simultaneously in four countries also showed that procedures and timelines have to be adapted to national contexts. Overall, the instrument can make an important contribution to understanding and informing physical activity policy, especially when used as an add-on to regular monitoring tools like the EU HEPA Monitoring Framework.

  • The Analysis of Cross-Polarisation Discrimination for Body Area Networks in Cylindrical Metallic Environment
    • Andrzej Ambroziak
    • Krzysztof Cwalina
    • Piotr Rajchowski
    2021

    The analysis of cross-polarisation discrimination for Body Area Networks in an untypical environment of cylindrical metallic room has been performed in the paper. This analysis was done based on the measurements carried out for dynamic narrowband off-body channels operating at the frequency of 2.45 GHz. The results have shown that there is a strong dependence of the depolarisation effect on the existence of direct component in the radio channel.

  • The assessment of metrological properties of segmental orifice based on simulations and experiments
    • Anna Golijanek-Jędrzejczyk
    • Andrzej Mrowiec
    • Robert Hanus
    • Marcin Zych
    • Marcin Heronimczak
    • Dariusz Świsulski
    2021 Full text MEASUREMENT

    Segmental orifices are often used to measure flows of heterogeneous mixtures, especially in flow meters in the power industry, for example. The orifice (with module m= 0.25) was installed in a stainless-steel pipe with internal diameter of 50 mm, placed in a hydraulic water system. The research was performed for Reynolds numbers ranging from 9,000 to 17,000. The flow characteristics of this orifice obtained based on simulation in SolidWorks Flow Simulation 2014 and experimental data were compared with standard-based calculations. It was determined that relative differences between the obtained flow characteristics did not exceed 1.5% for the experiment and 5.1% for the simulation. The article also presents the results of estimated uncertainty for mass flow measurement qm using the analytical method and the Monte Carlo simulations. The results for both methods proved that the relative expanded uncertainty Urel(qm) does not exceed 1.8% for the tested orifice.

  • The bile salt content of human bile impacts on simulated intestinal proteolysis of β-lactoglobulin
    • Dorota Dulko
    • Robert Staroń
    • Lukasz Krupa
    • Neil Rigby
    • Alan Mackie
    • Krzysztof Gutkowski
    • Andrzej Wasik
    • Adam Macierzanka
    2021 Full text FOOD RESEARCH INTERNATIONAL

    The gastrointestinal hydrolysis of food proteins has been portrayed in scientific literature to predominantly depend on the activity and specificity of proteolytic enzymes. Human bile has not been considered to facilitate proteolysis in the small intestine, but rather to assist in intestinal lipolysis. However, human bile can potentially influence proteins that are largely resistant to gastric digestion, and which are mainly hydrolysed after they have been transferred to the small intestine. We used purified and food-grade bovine milk β-lactoglobulin (βLg) to assess the impact of bile salts (BS) on the in vitro gastrointestinal digestion of this protein. Quantitative analysis showed that the proteolysis rate increased significantly with increasing BS concentration. The effect was consistent regardless of whether individual BS or real human bile samples, varying in BS concentrations, were used. The total BS content of bile was more important than its BS composition in facilitating the proteolysis of βlg. We also show that the impact of human bile observed during the digestion of purified βLg and βLg-rich whey protein isolate can be closely replicated by the use of individual BS mixed with phosphatidylcholine. This could validate simple BS/phosphatidylcholine mixtures as human-relevant substitutes of difficult-to-obtain human bile for in vitro proteolysis studies.

  • The cement-bone bond is weaker than cement-cement bond in cement-in-cement revision arthroplasty. A comparative biomechanical study
    • Marcin Ceynowa
    • Krzysztof Żerdzicki
    • Paweł Kłosowski
    • Maciej Zrodowski
    • Rafał Pankowski
    • Marek Rocławski
    • Tomasz Mazurek
    2021 Full text PLOS ONE

    This study compares the strength of the native bone-cement bond and the old-new cement bond under cyclic loading, using third generation cementing technique, rasping and contamination of the surface of the old cement with biological tissue. The possible advantages of additional drilling of the cement surface is also taken into account. Femoral heads from 21 patients who underwent a total hip arthroplasty performed for hip arthritis were used to prepare bone-cement samples. The following groups of samples were prepared. A bone— cement sample and a composite sample of a 6 weeks old cement part attached to new cement were tested 24 hours after preparation to avoid bone decay. Additionally, a uniform cement sample was prepared as control (6 weeks polymerization time) and 2 groups of cement-cement samples with and without anchoring drill hole on its surface, where the old cement polymerized for 6 weeks before preparing composite samples and then another 6 weeks after preparation. The uniaxial cyclic tension-compression tests were carried out using the Zwick-Roell Z020 testing machine. The uniform cement sample had the highest ultimate force of all specimens (n = 15; Rm = 3149 N). The composite cement sample (n = 15; Rm = 902 N) had higher ultimate force as the bone-cement sample (n = 31; Rm = 284 N; p <0.001). There were no significant differences between composite samples with 24 hours (n = 15; Rm = 902 N) and 6 weeks polymerization periods (n = 22; Rm = 890 N; p = 0.93). The composite cement samples with drill hole (n = 16; Rm = 607 N) were weaker than those without it (n = 22; Rm = 890 N; p < 0.001). This study shows that the bond between the old and new cement was stronger than the bond between cement and bone. This suggests that it is better to leave the cement that is not loosened from the bone and perform cement in cement revision, than compromising bone stock by removal of the old cement with the resulting weaker cement-bone interface. The results support performing cement-in-cement revision arthroplasty The drill holes in the old cement mantle decrease cement binding strength and are not recommended in this type of surgery.

  • The Chemical and Biological Properties of Nanohydroxyapatite Coatings with Antibacterial Nanometals, Obtained in the Electrophoretic Process on the Ti13Zr13Nb Alloy
    • Michał Bartmański
    • Łukasz Pawłowski
    • Anna Belcarz
    • Agata Przekora
    • Grazyna Ginalska
    • Gabriel Strugała
    • Bartłomiej Cieślik
    • Anna Pałubicka
    • Andrzej Zieliński
    2021 Full text INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    The risk of an early inflammation after implantation surgery of titanium implants has caused the development of different antimicrobial measures. The present research is aimed at characterizing the effects of nanosilver and nanocopper dispersed in the nanohydroxyapatite coatings, deposited on the Ti13Zr13Nb alloy, and on the chemical and biological properties of the coatings.The one-stage deposition process was performed by the electrophoretic method at different contents of nanomaterials in suspension. The surface topography of the coatings was examined with scanning electron microscopy. The wettability was expressed as the water contact angle. The corrosion behavior was characterized by the potentiodynamic technique. The release rate of copper and silver into the simulated body fluid was investigated by atomic absorption spectrometry. The antibacterial efficiency was evaluated as the survivability and adhesion of the bacteria and the growth of the biofilm. The cytotoxicity was assessed for osteoblasts. The results demonstrate that silver and copper increase the corrosion resistance and hydrophilicity. Both elements together effectively kill bacteria and inhibit biofilm growth but appear to be toxic for osteoblasts. The obtained results show that the nanohydroxyapatite coatings doped with nanosilver and nanocopper in a one-stage electrophoretic process can be valuable for antibacterial coatings.

  • The Cluster Organization. Analyzing the Development of Cooperative Relationships
    • Anna Lis
    • Adrian Lis
    2021

    Cluster organizations are becoming more and more popular, both in developing and developed countries. Considering the development of cluster policy and the related dynamic growth of cluster initiatives in the world, the lack of sufficient knowledge on the development of cooperation in cluster organizations inhibits their development and, in many cases, causes their complete disintegration. 　 The book provides new important elements to the current system of knowledge, filling in cognitive and research gaps in the scientific literature on problems related to cooperation in cluster organizations. The most valuable features for the reader concern the epistemological, methodological, and application aspects. The new element includes a theoretical concept, which refers to the trajectory of development of cooperative relationships in cluster organizations that facilitates the understanding and explanation of mechanisms responsible for cooperation in such organizations. 　 The concept also has great practical advantages, especially for people implementing the idea of "clustering": coordinators, facilitators, and members of cluster organizations as well as politicians and public authorities are responsible for shaping and implementing the cluster policy. It will be of value to researchers, academics, and students in fields with an interest in organizational studies, management of innovation and technology, strategic management, industrial economics, and economic geography.

  • THE COMPOSITION MODULATION EFFECT IN GaInPAs SOLID SOLUTIONS AS A MANIFESTATION OF ENERGY RESONANCE AFTER MATERIAL'S SPINODAL DECOMPOSITION
    • Pavel Moskvin
    • S.i. Skurativskyi
    • O.a. Gromovyi
    • Wojciech Sadowski
    2021 Full text Journal of Physical Studies

    The Cahn-Hilliard model concepts are extended to describe the spinodal decomposition of Ga$_x$In$_{1-x}$P$_y$As$_{1-y}$ solid solutions grown on the InP substrate. The energy of elastic deformation of the thin layer of a solid solution was calculated on the assumption of its coherent conjugation with the massive InP substrate. The excess energy of component mixing in the solid phase was modeled in accordance with the simple solution model, when the simultaneous substitution of components in the metal and metalloid sub lattices of the sphalerite structure is incorporated. The system of differential equations describing variations of the composition of a semiconductor solid solution after its spinodal decomposition was solved numerically under various thermodynamic conditions.

  • The Concept of Accuracy Analysis of the Vertical Displacements Gained from the Hydrostatic Levelling Systems’ Measurements
    • Waldemar Kamiński
    2021 Full text SENSORS

    Abstract: Nowadays, hydrostatic levelling is a widely used method for the vertical displacements’ determinations of objects such as bridges, viaducts, wharfs, tunnels, high buildings, historical buildings, special engineering objects (e.g., synchrotron), sports and entertainment halls. The measurements’ sensors implemented in the hydrostatic levelling systems (HLSs) consist of the reference sensor (RS) and sensors located on the controlled points (CPs). The reference sensor is the one that is placed at the point that (in theoretical assumptions) is not a subject to vertical displacements and the displacements of controlled points are determined according to its height. The hydrostatic levelling rule comes from the Bernoulli’s law. While using the Bernoulli’s principle in hydrostatic levelling, the following components have to be taken into account: atmospheric pressure, force of gravity, density of liquid used in sensors places at CPs. The parameters mentioned above are determined with some mean errors that influence on the accuracy assessment of vertical displacements. In the subject’s literature, there are some works describing the individual accuracy analyses of the components mentioned above. In this paper, the author proposes the concept of comprehensive determination of mean error of vertical displacement (of each CPs), calculated from the mean errors’ values of components dedicated for specific HLS. The formulas of covariances’ matrix were derived and they enable to make the accuracy assessment of the calculations’ results. The author also presented the subject of modelling of vertical displacements’ gained values. The dependences, enabling to conduct the statistic tests of received model’s parameters, were implemented. The conducted tests make it possible to verify the correctness of used theoretical models of the examined object treated as the rigid body. The practical analyses were conducted for two simulated variants of sensors’ connections in HLS. Variant no. I is the sensors’ serial connection. Variant no. II relies on the connection of each CPs with the reference sensor. The calculations’ results show that more detailed value estimations of the vertical displacements can be obtained using variant no. II.

  • The concept of suspended urban rail vehicle
    • Mateusz Kuczyk
    • Piotr Jędrzejewski
    • Paweł Załuski
    2021 Full text Pojazdy Szynowe

    Niniejsza publikacja została poświęcona szczegółowemu opisowi proponowanej przez autorów koncepcji podwieszanego pojazdu szynowego. W pierwszej kolejności przeanalizowano istniejące rozwiązania, wraz ze wskazaniem ich podstawowych wad i zalet. Następnie opisano proponowaną konstrukcję w zakresie: budowy wagonu, sposobu jego zawieszenia oraz prowadzenia po zadanym torze ruchu. Artykuł ten powstał na podstawie pracy dyplomowej pt. „Koncepcja wagonu silnikowego kolei podwieszanej”, na wydziale Mechanicznym Politechniki Gdańskiej.

  • The Conceptual Research over Low-Switching Modulation Strategy for Matrix Converters with the Coupled Reactors
    • Paweł Szczepankowski
    • Jarosław Łuszcz
    • Aleksander Usoltsev
    • Natalia Strzelecka
    • Enrique Romero-Cadaval
    2021 Full text ENERGIES

    In this paper, different Pulse Width Modulation (PWM) strategies for operating with a low-switching frequency, a topology that combines Conventional Matrix Converters (CMCs), and Coupled Reactors (CRs) are presented and discussed. The principles of the proposed strategies are first discussed by a conceptual analysis and later validated by simulation. The paper shows how the combination of CMCs and CRs could be of special interest for sharing the current among these converters’ modules, being possible to scale this solution to be a modular system. Therefore, the use of coupled reactors allows one to implement phase shifters that give the solution the ability to generate a stair-case load voltage with the desired power quality even the matrix converters are operated with a low-switching frequency close to the grid frequency. The papers also address how the volume and weight of the coupled reactors decrease with the growth of the fundamental output frequency, making this solution especially appropriate for high power applications that are supplied at high AC frequencies (for example, in airport terminals, where a supply of 400 Hz is required).

  • The construction of suspended rail vehicle bogie
    • Mateusz Kuczyk
    • Piotr Jędrzejewski
    • Paweł Załuski
    2021 Full text Pojazdy Szynowe

    Niniejsza publikacja została poświęcona szczegółowemu opisowi wózka, przeznaczonego do wykorzystania w proponowanej przez autorów koncepcji podwieszanego pojazdu szynowego. W pierwszej kolejności skrótowo opisano rzeczony pojazd, ze szczególnym naciskiem na parametry determinujące konstrukcję wózków. Następnie zostały omówione zastosowane rozwiązania konstrukcyjne w zakresie budowy poszczególnych podzespołów wózka, takich jak: zestawy kołowe, rama, dwustopniowe usprężynowanie, układ napędowy i hamulcowy. Artykuł ten powstał na podstawie pracy dyplomowej pt. „Koncepcja wagonu silnikowego kolei podwieszanej”, na wydziale Mechanicznym Politechniki Gdańskiej.

  • The description of non-linear interactions of wave and non-wave modes in a non-adiabatic plasma flow
    • Anna Perelomova
    2021 Full text CONTRIBUTIONS TO PLASMA PHYSICS

    The method of derivation of non-linear equations for interacting modes is explained and applied to a plasma's flow affected by a magnetic field. It is based on the linear projecting of the total perturbation field into specific variations of variables in individual modes of a flow. The method may be applied in many examples of fluid flows with different mechanisms of non-adiabaticity. It is of special importance in complex flows with large number of different modes. A flow of an ionized gas is one of the examples of such flows: it incorporates fast, slow magnetosonic modes, the Alfvén mode and the entropy mode. In the frames of this study, the wave vector may form an arbitrary angle urn:x-wiley:08631042:media:ctpp202100067:ctpp202100067-math-0001 with the straight equilibrium magnetic field. Thermal conduction, dynamic viscosity and a generic heating–cooling function, which is responsible for an energy inflow and radiative losses, are taken into account. Variable urn:x-wiley:08631042:media:ctpp202100067:ctpp202100067-math-0002 and plasma-β, diversity of the wave modes and a balance of different mechanisms of non-adiabaticity make the description of non-linear interaction of modes special. The non-linear excitation of the magnetosonic mode by the entropy mode is considered as an example.

  • The Determinants of False Self-Employment: A Survey of Polish Enterprises
    • Dagmara Nikulin
    2021 EASTERN EUROPEAN ECONOMICS

    The main goal of this article is to advance the emergent research on tax evasion in Poland in the form of false self-employment (FSE), in particular to identify its causes. The dependent character of some self-employed workers is a big problem in the Polish economy, which has been completely unexplored because of the lack of available data. In this article, we use data from a survey of Polish companies. Our empirical results show the highest prevalence of FSE in construction and to lesser extent in the services and retail, at micro and small firms, and at firms whose owners or managers are characterized by lower tax morality.

  • The Development of a Combined Method to Quickly Assess Ship Speed and Fuel Consumption at Different Powertrain Load and Sea Conditions
    • Przemysław Krata
    • Aleksander Kniat
    • Roberto Vettor
    • Hubert Krata
    • Carlos Guedes Soares
    2021 Full text TransNav - The International Journal on Marine Navigation and Safety of Sea Transportation

    Decision support systems (DSS) recently have been increasingly in use during ships operation. They require realistic input data regarding different aspects of navigation. To address the optimal weather routing of a ship, which is one of the most promising field of DSS application, it is necessary to accurately predict an actually attainable speed of a ship and corresponding fuel consumption at given loading conditions and predicted weather conditions. In this paper, authors present a combined calculation method to predict those values. First, a deterministic modeling is applied and then an artificial neural network (ANN) is structured and trained to quickly mimic the calculations. The sensitivity of the ANN to adopted settings is analyzed as well. The research results confirm a more than satisfactory quality of reproduction of speed and fuel consumption data as the ANN response meet the calculation results with high accuracy. The ANN-based approach, however, requires a significantly shorter time of execution. The directions of future research are outlined.

  • The Effect of Cobalt Incorporation into Nickel–Iron Oxide/(oxy)hydroxide Catalyst on Electrocatalytic Performance Toward Oxygen Evolution Reaction
    • Karolina Cysewska
    • Marcin Zając
    • Marcin Łapiński
    • Jakub Karczewski
    • Maria Rybarczyk
    • Bartosz Kamecki
    • Piotr Jasiński
    • Sebastian Molin
    2021 Energy Technology

    This work presents a study on the influence of the addition of cobalt into state-of-the-art nickel–iron (NiFe) mixed oxides/hydroxides/(oxy)hydroxides on their structural and morphological properties, and oxygen evolution reaction (OER) catalytic activity. A one-step electrodeposition process is performed without any additives to fabricate NiFe and x cobalt-doped nickel/iron (xCoNiFe) layer-double-hydroxide catalysts directly on nickel foam. The addition of cobalt nitrate in the synthesis solution significantly affects the final form of the catalyst: the addition of 2 mm cobalt nitrate into the aqueous solution of 4 mm nickel and iron nitrate stabilizes the electrochemical synthesis of the catalyst, which leads to the formation of a homogenously spread 3D interconnected structure with a high electroactive surface area (0.07 cm2, 1.1 m2 cm−2: including nickel foam substrate); it induces the formation of Ni3+ desirable for the formation of the catalytically active (oxy)hydroxides, which is not observed for the state-of-the-art NiFe. The significant role of the addition of cobalt translates into improved preliminary OER catalytic stability and activity of the catalyst with an onset potential of 1.40 V, overpotential of 224 mV determined at 10 mA cm−2, and only 0.7% loss in stability after 22 h working in alkaline conditions compared with the initial parameters.