Eva Gutierrez-Berasategui

Photoelectrochemical reduction of CO ₂ into energy‐dense hydrocarbons represents a promising strategy for sustainable fuel production and in situ resource utilization. This is particularly attractive in extraterrestrial environments where CO ₂ ‐rich atmospheres and solar energy are readily available, enabling the conversion of locally available resources into fuels and chemical feedstocks while reducing reliance on Earth‐supplied materials. In this work, BiVO ₄ and BiVO ₄ /WO ₃ photoanodes are fabricated by magnetron sputtering and integrated into a photoelectrochemical system with a Cu‐based gas diffusion cathode for selective CO ₂ reduction to CH ₄ using greywater as electrolyte. The BiVO ₄ /WO ₃ heterojunction enhances charge separation and electron transport, achieving optimal performance with thicknesses of 100 nm (BiVO ₄ ) and 130 nm (WO ₃ ), with a CH ₄ faradaic efficiency of 47.9%, an energy‐to‐fuel conversion efficiency of 2.7%, and a production rate of 36.7 µmol m ^{− 2} s ^{− 1} under gas‐phase operation. These results highlight the potential of heterojunction engineering and scalable sputtering deposition for high‐performance photoelectrochemical CO ₂ conversion toward solar‐driven CH ₄ production.

This paper presents a study on the development and optimisation of thin films of nickel-vanadium oxide (NiV_xO_y) deposited by DC reactive magnetron sputtering (RMS) controlled by P.E.M. (plasma emission monitoring). The hysteresis behaviour of the Ni emission signal as a function of oxygen incorporation was analysed using optical emission spectroscopy (OES), enabling the identification of critical working points along the hysteresis loop and their correlation with film growth mechanisms. Compared to the non-monotonic nature of the target discharge voltage signal, OES provided a simplified response for real-time process control. A set of coatings was deposited under various working pressures (0.6 and 2.0 Pa) and plasma emission monitoring (P.E.M.) conditions and was thoroughly characterised in terms of microstructure, composition, optical modulation, and electrochemical performance. Films deposited at high pressure and under 30% P.E.M. conditions showed an optimal balance between optical modulation (21%) and charge density (4 mC/cm²), which was attributed to the increased Ni³⁺ content and the surface cracks at low density.

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.

Cast Al-Si alloys, recognized for their excellent mechanical properties, constitute one of the most widely employed non-ferrous substrates in several sectors, and are particularly relevant in the transport industry. Nevertheless, these alloys also display inherent limitations that significantly restrict their use in several applications. Among these limitations, their low hardness, low wear resistance, or limited anti-corrosion properties, which are often not enough when the component is subjected to more severe environments, are particularly relevant. In this context, surface modification and the development of coatings are essential for the application of cast Al-Si alloys. This review focuses on the development of coatings to overcome the complexities associated with improving the performance of cast Al-Si alloys. Against this background, plasma electrolytic oxidation (PEO), an advanced electrochemical treatment that has revolutionized the surface modification of several metallic alloys in recent years, emerges as a promising approach. Despite the growing recognition of PEO technology, the achievement of high-performance coatings on cast Al-Si is still a challenge nowadays, for which reason this review aims to provide an overview of the PEO treatment applied to these alloys. In particular, the impact of the electrolyte chemical composition on the properties of the coatings obtained on different alloys exposed to harsh environments has been analyzed and discussed. By addressing the existing gaps and challenges, this paper contributes to a better understanding of the intricacies associated with the development of robust PEO coatings on cast Al-Si alloys.

Indium tin oxide (ITO) thin films are widely used as transparent electrodes in electronic devices. Many of those electronic devices are heat sensitive, thus their manufacturing process steps should not exceed 100 °C. Manufacturing competitive high-quality ITO films at low temperature at industrial scale is still a challenge. Magnetron sputtering technology is the most suitable technology fulfilling those requirements. However, ITO layer properties and the reproducibility of the process are extremely sensitive to process parameters. Here, morphological, structural, electrical, and optical characterization of the ITO layers deposited at low temperature has been successfully correlated to magnetron sputtering process parameters. It has been demonstrated that the oxygen flow controls and influences layer properties. For oxygen flow between 3–4 sccm, high quality crystalline layers were obtained with excellent optoelectronic properties (resistivity 80%). The optimized conditions were applied to successfully manufacture transparent ITO heaters on large area glass and polymeric components. When a low supply voltage (8 V) was applied to transparent heaters (THs), de-icing of the surface was produced in less than 2 min, showing uniform thermal distribution. In addition, both THs (glass and polycarbonate) showed a great stability when exposed to saline solution.