This work is focused on the thermophysical and tribological study of eight nanolubricant compositions based on a polyalphaolefin (PAO 20) and two different nanoadditives: multi-walled carbon nanotubes (MWCNTs) and hexagonal boron nitride (h-BN). Regarding the thermophysical properties, density and dynamic viscosity of the base oil and the nanolubricants were measured in the range of 278.15–373.15 K, as well as their viscosity index, with the aim of evaluating the variation of these properties with the addition of the nanoadditives. On the other hand, their lubricant properties, such as contact angle, coefficient of friction, and wear surface, were determined to analyze the influence of the nanoadditives on the tribological performance of the base oil. The results showed that MWCNTs and h-BN nanoadditives improved the wear area by 29% and 37%, respectively, at a 0.05 wt% concentration. The density and dynamic viscosity increased compared with the base oil as the nanoadditive concentration increased. The addition of MWCNTs and h-BN nanoparticles enhanced the tribological properties of PAO 20 base oil.

The development of cost-effective components for Proton Exchange Membrane (PEM) electrolyzers plays a crucial role in the transformation of renewable energy into hydrogen. To achieve this goal, two main issues should be addressed: reducing the Platinum Group Metal (PGM) content present on the electrodes and finding a large-scale electrode manufacturing method. Magnetron sputtering could solve these hurdles since it allows the production of highly pure thin films in a single-step process and is a well-established industrial and automated technique for thin film deposition. In this work, we have developed an ultra-low 0.1 mg cm⁻² Pt loading electrode using magnetron sputtering gas aggregation method (MSGA), directly depositing the Pt nanoparticles on top of the carbon substrate, followed by a complete evaluation of the electrochemical properties of the sputtered electrode. These ultra-low Pt content electrodes have been thoroughly characterized and tested in a real electrolyzer cell. They demonstrate similar efficiency to commercial electrodes with a Pt content of 0.3 mg/cm², achieving a 67% reduction in Pt loading. Additionally, durability tests indicate that these electrodes offer greater stability compared to their commercial counterparts. Thus, magnetron sputtering has been proven as a promising technology for manufacturing optimum high-performance electrodes at an industrial scale.

The sol–gel method provides a simple and versatile synthesis route to prepare photocatalytic coatings of benchmark catalyst titanium oxide (TiO₂). However, photoactive TiO₂ coatings require to be annealed at relatively high temperatures and this fact limits the type of substrate on which it can be used. In this study, hybrid transparent films based on the 2-aminobenzene-1,4-dicarboxylato (NH₂BDC) ligand and titanium(IV) oxide were deposited on glass and polycarbonate substrates by immersing into a sol and annealing at 80 and 150 °C. Doped coatings exhibited a significant redshift of the band gap (2.37 eV) compared to that provided by neat TiO₂ coatings (3.29–3.36 eV). The photocatalytic study of the films was carried out by assessing the photodegradation of a dye in aqueous solution. In this sense, when NH₂BDC-sensitized coatings were illuminated with visible light, they surpassed the dye removal ability provided by neat TiO₂ cured at 450 °C even when the latter was activated with UV light. Apart from this, while TiO₂ coating performed best at low pH values (pH = 2–3), doped coatings exhibited their maximum performance at pH values of 4–6, closer to the freshwater pH range. The type of substrate and heat treatment influenced the final roughness of the film. Rougher films exhibited greater dye-adsorption capability, whereas denser coatings proved to be more effective in dye photodegradation. All doped coatings showed good adhesion with the substrates and medium hardness, despite the low annealing temperature.

Accurate electrochemical modelling of hydrogen fuel cells (FCs) is essential for performance optimization and comparative analysis of different cell configurations. This study presents the electrochemical characterization of a reference FC with graphite bipolar plates, utilizing voltammetry and electrochemical impedance spectroscopy (EIS). The primary objective is to develop a reliable electrical equivalent model of the reference cell, which will serve as a benchmark for future investigations involving alternative FC designs and materials. A detailed methodology for extracting the electrical model from Nyquist plots is provided, ensuring a robust correlation between impedance characteristics and FC operation. The validity of the proposed model is confirmed through polarization curve analysis, establishing its applicability for predictive diagnostics. Additionally, a comprehensive description of the experimental setup configuration and reference components description is included to facilitate reproducibility and further refinement of FC modelling techniques. The findings contribute to the standardization of EIS-based FC analysis, supporting the development of improved electrochemical models for nextgeneration hydrogen energy systems.