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The development in the field of nanomaterials has resulted in the synthesis of various structures. Depending on their final applications, the desired composition and therefore alternate properties can be achieved. In electrochemistry, the fabrication of bulk films characterized by high catalytic performance is well-studied in the literature. However, decreasing the scale of materials to the nanoscale significantly increases the active surface area, which is crucial in electrocatalysis. In this work, a special focus is placed on the electrodeposition of nanocones and their application as catalysts in hydrogen evolution reactions. The main paths for their synthesis concern deposition into the templates and from electrolytes containing an addition of crystal modifier that are directly deposited on the substrate. Additionally, the fabrication of cones using other methods and their applications are briefly reviewed.

Porous Ni, Ni–Ir, and Ni–Pt electrodes were prepared on Ni substrates by molten-salt Al co-deposition followed by dealloying. SEM/EDS and XRD confirmed a Raney-type porous network with Ir or Pt present across the layer. A urea oxidation reaction (UOR) was tested in 1 M NaOH + 0.33 M urea by cyclic voltammetry and chronoamperometry at +0.40 V vs. SCE (60 min). Smooth Ni showed near-zero current. Porous Ni resulted in ~11 mA cm−2 initially and ~9 mA cm−2 after 60 min. Porous Ni–Ir started at ~7 mA cm−2 and fell to ~2 mA cm−2 within 5 min, indicating fast deactivation, likely due to Ir-oxide formation that suppresses the Ni2+/Ni3+ redox couple. Porous Ni–Pt remained at ~11 mA cm−2 over 60 min, consistent with a stable Ni–Pt effect in which Pt aids urea adsorption/activation while Ni provides the redox path for oxidation. Overall, Pt improves UOR performance, whereas Ir lowers it under these conditions.

Ammonium chloride is a commonly used crystal modifier allowing the production of conical structures. Metals and alloys synthesized in the form of cones show enhanced catalytic activity and active surface area. Ni-Cu alloys as candidates for catalysts in the hydrogen evolution reaction were synthesized using a one-step method. The influence of the NH4Cl content on morphology, chemical and physical composition, wettability, roughness, and catalytic properties was analyzed using many techniques, including, inter alia, Scanning Electron Microscopy, X-ray Diffraction, Atomic Force Microscopy, and Linear Sweep Voltammetry. The proposed deposition parameters allow the successful synthesis of conical Ni-Cu structures with promising catalytic activity compared with other coatings of these alloys. The lowest determined value of the Tafel slope is 79 mV/dec for the sample deposited from the electrolyte with 40 g/L NH4Cl.

The electrochemistry research team activity from Poland is marked by significant increase in the last 20 years. The joining of European Community in 2004 gives an impulse for the development of Polish science. The development of electrochemistry has been stimulated by cooperation with industry and the establishment of technology transfer centers, technology parks, business incubators, etc. and the mostly by simplified international collaborations. Five research institutions from Krakow reports work in the field of electrochemistry. The achievements of all teams are briefly described.

Gold thin films were deposited on quartz substrates by DC magnetron sputtering to fabricate electrodes for electrochemical and resistive sensing applications. The influence of sputtering parameters on film thickness, structure, and electrical properties was systematically investigated. XRD analysis revealed a predominant (111) crystallographic orientation. Microstrain values, determined via Williamson–Hall (W–H) analysis, were low (below 0.013) and closely correlated with surface roughness trends. AFM measurements showed that the surface roughness increased with film thickness. Electrical resistivity decreased linearly with increasing thickness and exhibited a critical grain size of approximately 25 nm, beyond which conductivity improved markedly. These results demonstrate the strong dependence of Au thin-film morphology and performance on deposition conditions, offering practical guidelines for optimizing their application in functional sensing devices.

In the paper, the mechanism of the process of the Rh(III) ions adsorption on activated carbon ORGANOSORB 10—AA was investigated. It was shown, that the process is reversible, i.e., stripping of Rh(III) ions from activated carbon to the solution is also possible. This opens the possibility of industrial recovery of Rh (III) ions from highly dilute aqueous solutions. The activation energies for the forward and backward reaction were determined These are equal to c.a. 7 and 0 kJ/mol. respectively. Unfortunately, the efficiency of this process was low. Obtained maximum load of Rh(III) was equal to 1.13 mg per 1 g of activated carbon.

Among oxygen sensors, types such as polymer-, ceramic-, or carbon-based ones may be distinguished. Particular interest in semiconductor metal oxide (SMO) sensors has recently been observed. This is due to their easy fabrication process, high control over the final product (dopants, posttreatment, etc.), and high concentration of oxygen vacancies, by which they show significant changes in electrical properties when exposed to analyte. In this review, different types of sensors are described and categorized. Importantly, their limitations, challenges and principles of sensing mechanism are also discussed, wherein attention is primarily paid to semiconductor metal oxide (SMO) oxygen sensors. This comprehensive review provides an in-depth analysis of the existing literature on planar SMO oxygen sensors, focusing on various materials, fabrication techniques, and sensing mechanisms. It also critically assesses the challenges and limitations in current research, offering insights into future directions for developing highly efficient and reliable sensors. Currently, most oxygen resistive sensors are a few micrometers thick and operate at high temperatures, which leads to high power consumption. To highlight importance of this topic, a market overview is also presented.

Ni–Cu alloys are suitable candidates as catalysts in hydrogen evolution reaction. Because of the different magnetic properties of Ni and Cu, the influence of an applied external magnetic field on the synthesis Ni–Cu alloys was studied. The coatings were prepared with visible changes in their appearance. The differences between the observed regions were studied in terms of morphology and chemical composition. In addition, the overall chemical and phase compositions were determined using X-ray fluorescence and X-ray diffraction methods, respectively. The catalytic activity was measured in 1 M NaOH using linear sweep voltammetry. The contact angle was determined using contour analysis. All samples were hydrophilic. Hydrogen evolution started at different times depending on the area on the surface. It started earliest on the coating obtained in parallel to the electrode magnetic field at 250 mT. We found that when the Lorenz force is maximal, Cu deposition is preferred because of the enhancement of mass transport.

In this work, we report on the fabrication of ZnO thin films doped with Ge via the ALD method. With an optimized amount of Ge doping, there was an improvement in the conductivity of the films owing to an increase in the carrier concentration. The optical properties of the films doped with Ge show improved transmittance and reduced reflectance, making them more attractive for opto-electronic applications. The band gap of the films exhibits a blue shift with Ge doping due to the Burstein–Moss effect. The variations in the band gap and the work function of ZnO depend strongly on the carrier density of the films. From the surface studies carried out using XPS, we could confirm that Ge replaces some of the Zn in the wurtzite structure. In the films containing Ge, the concentration of oxygen vacancies is also high, which is somehow related to the poor electrical properties of the films at higher Ge concentrations.

The work reports the synthesis and characterization of ternary nanoalloy catalysts of silver, bismuth, and rhenium from alkaline solutions containing L–cysteine as a complexing agent and sodium borohydride as a reducing agent. UV–Vis spectra and dynamic light scattering (DLS) analyses of the obtained colloids were performed. Additionally, high-resolution transmission electron microscope (HR–TEM) analysis assisted the former investigations. The influence of a stabilizer (PVA) was demonstrated for bismuth nanoparticles reaching an average size of 8 nm with PVA, whereas they grew large, 514 nm, in the case of synthesis without stabilizing agent. AgReBi nanoalloy particles reach an average size of 19 nm with PVA. The presence of two absorption maxima in the UV–Vis spectrum suggests shape anisotropy of these nanoparticles. TEM micrographs demonstrate the crystal structure of AgReBi nanoparticles. Cyclic voltamaperometry allows for deciphering of the catalytic properties for hydrogen peroxide electro-reduction. Both bismuth and AgReBi nanoalloy catalysts showed relatively high catalytic activity in H2O2 electro-reduction in the amperometric tests.