João Pedro Jenson de Oliveira

This paper provides a brief review of biogas contaminants, examining the impact of hydrogen sulfide (H₂S), nitrogen (N₂), and ammonia (NH₃) on catalytic reforming processes and Solid Oxide Fuel Cells (SOFCs) electricity generation. Biogas, produced through anaerobic digestion (AD), is a promising renewable energy source that can be upgraded into biomethane and reformed into H₂-rich syngas for SOFCs. Despite this, contaminants like H₂S found in biogas and biomethane cause critical issues such as catalyst poisoning, decreased electrochemical performance, and higher maintenance costs, while NH₃, potentially formed from N₂ during reforming, can lead to catalyst degradation and reduced SOFC performance, representing an underexplored contamination pathway. This review highlights the negative impacts of H₂S, N₂, and NH₃ on catalytic reforming and SOFCs, causing catalyst deactivation and performance loss, thus reinforcing the importance of developing advanced purification methods and sulfur-tolerant materials to improve renewable hydrogen (H₂) production and fuel cell durability.

Metal-supported solid oxide fuel cells (MS-SOFCs) have garnered increasing attention for advancing energy converter devices owing to their mechanical robustness, fast thermal cycling, and ability to operate with a wide range of fuels such as hydrocarbons and biofuels without contaminations. However, the manufacturing of porous metallic supports (PMSs), a critical component of these cells, still presents significant challenges, particularly regarding oxidation resistance, mismatch in thermal expansion coefficients (CTEs), gas diffusion issues, and synthesis reproducibility. In this work, we report a reproducible water-based tape casting methodology for PMS fabrication using commercially available 410S stainless steel powder. This alloy was selected due to their CTE compatibility with MS-SOFC ceramic layer components and due to its excellent chromium content (11.5–14.5%) to improve corrosion resistance. The optimized slurry formulation, containing tailored amounts of water-soluble binders and plasticizers, offers flexible and defect-free green tapes. Rheological characterization confirmed pseudoplastic and thixotropic behavior with high recovery (91.5%) after shear, ensuring stability during casting. Thermal gravimetric analysis (TGA) guided the debinding profile to prevent structural damage, and sintering was conducted under air and argon atmospheres. Argon sintering preserved the metallic structure and chromium content, while air sintering led to severe oxidation and phase destabilization. Precalcined ZrO₂ nonstick coarse powder at 1600 °C for 2 h was used during sintering to prevent contamination from Al₂O₃. A well-developed lamellar microstructure and peculiar interconnected porosity were observed in the sintered PMS, both of which are fundamental for ensuring gas permeability in MS-SOFC applications. The permeability of the PMS was tested for H₂, obtaining a result of 5.85 to 8.36 × 10^–12 m². Additionally, the PMSs showed an average resistivity of 2.45 ± 0.28 Ω·cm. This process addresses several obstacles in PMS fabrication pathway for integrating PMSs into next-generation SOFC architectures.

This paper reports the use of nanoparticles (NPs)-modified voltammetric sensors for the rapid determination of glycerol in the presence of ethanol and methanol, which are used in the transesterification reaction of biodiesel production. Two different modified electrodes have been prepared to form the electronic tongue (ET): copper hexacyanoferrate NPs obtained by chemical synthesis and mixed into graphite/epoxy (GEC) electrode, and nickel hydroxide NPs electrodeposited in reduced graphene oxide onto a GEC electrode. The response characteristics of these electrodes were first evaluated by building the respective calibration against glycerol, ethanol, and methanol. The electrodes demonstrated good stability during their analytical characterization, while principal component analysis confirmed the differentiated response against the different alcohols. Finally, the quantification of mixtures of these substances was achieved by a genetic algorithm-artificial neural networks (GA-ANNs) model, showing satisfactory agreement between expected and obtained values.

The refrigeration industry produces millions of tons of waste polyurethane (PU) every year, which can cause environmental damage and human health problems. This article analyzes the use of waste PU as filler in composites made of styrene butadiene rubber (SBR) and natural rubber (NR) to produce shoe soles. The interfacial interaction of said filler was evaluated by the Flory–Rehner method (swelling) using the equation developed by Lorenz–Park. The results of this evaluation were later compared with those obtained by the Mooney–Rivlin method using the data from stress–strain tests. According to the results of the tensile strength tests, the composites filled with waste PU present stress–strain curves that are like those of metallic materials that have low elastic strength but high plastic strength. Using the Lorenz–Park equation, the filled composites examined in this study exhibited values above 0.7, which means a strong filler–rubber interaction. Scanning Electron Microscopy and Fourier‐Transform Infrared Spectroscopy were used to investigate the morphology of the composites in detail.