Production of hydrogen from methanol steam reforming using CuPd/ZrO2 catalysts – Influence of the catalytic surface on methanol conversion and CO selectivity

Electricity generation for mobile applications by proton exchange membrane fuel cells (PEMFCs) is typically hindered by the low volumetric energy density of hydrogen. Nevertheless, nearly pure hydrogen can be generated in-situ from methanol steam reforming (MSR), with Cu-based catalysts being the most common MSR catalysts. Cu-based catalysts display high catalytic performance, even at low temperatures (ca. 250 °C), but are easily deactivated. On the other hand, Pd-based catalysts are very stable but show poor MSR selectivity, producing high concentrations of CO as by-product. This work studies bimetallic catalysts where Cu was added as a promoter to increase MSR selectivity of Pd. Specifically, the surface composition was tuned by different sequences of Cu and Pd impregnation on a monoclinic ZrO₂ support. Both methanol conversion and MSR selectivity were higher for the catalyst with a CuPd-rich surface compared to the catalyst with a Pd-rich surface. Characterization analysis indicate that the higher MSR selectivity results from a strong interaction between the two metals when Pd is impregnated first (likely an alloy). This sequence also resulted in better metallic dispersion on the support, leading to higher methanol conversion. A H₂ production rate of 86.3 mmol h^?1 g^?1 was achieved at low temperature (220 °C) for the best performing catalyst.     

Life-cycle assessment of hydrogen technologies with the focus on EU critical raw materials and end-of-life strategies

We present the results of a life-cycle assessment (LCA) for the manufacturing and end-of-life (EoL) phases of the following fuel-cell and hydrogen (FCH) technologies: alkaline water electrolyser (AWE), polymer-electrolyte-membrane water electrolyser (PEMWE), high-temperature (HT) and low-temperature (LT) polymer-electrolyte-membrane fuel cells (PEMFCs), together with the balance-of-plant components. New life-cycle inventories (LCIs), i.e., material inputs for the AWE, PEMWE and HT PEMFC are developed, whereas the existing LCI for the LT PEMFC is adopted from a previous EU-funded project. The LCA models for all four FCH technologies are created by modelling the manufacturing phase, followed by defining the EoL strategies and processes used and finally by assessing the effects of the EoL approach using environmental indicators. The effects are analysed with a stepwise approach, where the CML2001 assessment method is used to evaluate the environmental impacts. The results show that the environmental impacts of the manufacturing phase can be substantially reduced by using the proposed EoL strategies (i.e., recycled materials being used in the manufacturing phase and replacing some of the virgin materials). To point out the importance of critical materials (in this case, the platinum-group metals or PGMs) and their recycling strategies, further analyses were made. By comparing the EoL phase with and without the recycling of PGMs, an increase in the environmental impacts is observed, which is much greater in the case of both fuel-cell systems, because they contain a larger quantity of PGMs.     

Recent progress in LiF materials for safe lithium metal anode of rechargeable batteries: Is LiF the key to commercializing Li metal batteries?

The lithium metal battery has attracted considerable attention as the ultimate lithium secondary battery for high energy density. However, safety issues and battery performance deterioration due to the growth of lithium dendrites have hampered the practical use of lithium metal batteries. Recently, lithium fluoride has been considered as a lithium metal protective layer to solve this problem. In this review, firstly, the results of the studies on dendrites and SEI that have been carried out to date are reviewed. Secondly, the results of studies on lithium fluoride are divided into additive, artificial SEI, and other methods and the possibilities of their practical use are discussed. Finally, the significance and limitations of the lithium fluoride studies are summarized, and general conclusions and prospects for recommended research directions to accelerate the commercialization of lithium metal batteries are presented.     

Design of tailored biodegradable implants: The effect of voltage on electrodeposited calcium phosphate coatings on pure magnesium

Magnesium, as a biodegradable metal, offers great potential for use as a temporary implant material, which dissolves in the course of bone tissue healing. It can sufficiently support the bone and promote the bone healing process. However, the corrosion resistance of magnesium implants must be enhanced before its application in clinical practice. A promising approach of enhancing the corrosion resistance is deposition of bioactive coating, which can reduce the corrosion rate of the implants and promote bone healing. Therefore, a well-designed substrate-coating system allowing a good control of the degradation behavior is highly desirable for tailored implants for specific groups of patients with particular needs. In this contribution, the influence of coating formation conditions on the characteristics of potentiostatically electrodeposited CaP coatings on magnesium substrate was evaluated. Results showed that potential variation led to formation of coatings with the same chemical composition, but very different morphologies. Parameters that mostly influence the coating performance, such as the thickness, uniformity, deposits size, and orientation, varied from produced coating to coating. These characteristics of CaP coatings on magnesium were controlled by coating formation potential, and it was demonstrated that the electrodeposition could be a promising coating technique for production of tailored magnesium-CaP implants.     

Antibiofilm activity of the essential oil of citronella (Cymbopogon nardus) and its major component,geraniol, on the bacterial biofilms of Staphylococcus aureus

Food Science and Biotechnology - Medicinal plants with antimicrobial action have been investigated for uses against biofilms, among which, Cymbopogon nardus, citronella, stands out as a promising...     

Antioxidant and antibacterial activities of a starch film with bioextracts microencapsulated from cactus fruits (Opuntia oligacantha)

Food Science and Biotechnology - The use of unconventional sources is very relevant in the food area. In the present study the development of active films with the addition of bioextract (BE) or...     

Waste waters from the leachate of mushroom as vine foliar treatments: influence on grape volatile composition over two consecutive seasons

Edible mushrooms production presents a potential problem for the environment, due to the large amount of waste generated. These wastes contain nitrogenous matter, which could be used as biostimulant in plants. The aim of this work was to study the effect of waste waters, from the mushroom production process, applied at veraison and 1 week later to grapevine leaves, on grape volatile compounds over two vintages. The results evidenced that mushroom water treatment decreased the grape content of certain terpenoids, C₁₃ norisoprenoids, benzenoid compounds and esters, increasing C6 compounds content during the first season. Treated mushroom water application slightly affected grape volatile composition. This was the treatment that least affected the content of grape volatile composition. Few differences were found after the biostimulation during the second vintage. The season was the dominant factor of grape volatile content variation compared to the treatment and their interaction.