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In the present work, multifunctional electrocatalysts formed by palladium nanoparticles (Pd NPs) loaded on Fe or Cu-containing composite supports, based on carbon nitride (C3N4) and super-activated carbon with a high porosity development (SBET 3180 m2/g, VDR 1.57 cm3/g, and VT 1.65 cm3/g), were synthesised. The presence of Fe or Cu sites favoured the formation of Pd NPs with small average particle size and a very narrow size distribution, which agreed with Density Functional Theory (DFT) calculations showing that the interaction of Pd clusters with C3N4 flakes is weaker than with Cu- or Fe-C3N4 sites. The electroactivity was also dependent on the composition and, as suggested by preliminary DFT calculations, the Pd-Cu catalyst showed lower overpotential for hydrogen evolution reaction (HER) while bifunctional oxygen reduction reaction/ oxygen evolution reaction (ORR/OER) behaviour was superior in Pd-Fe sample. The Pd-Fe electrocatalyst was studied in a zinc-air battery (ZAB) for 10 h, showing a performance similar to a commercial Pt/C + RuO2 catalyst with a high content of precious metal. This study demonstrates the synergistic effect between Pd species and transition metals and shows that transition metals anchored on C3N4-based composite materials promote the electroactivity of Pd NPs in HER, ORR and OER due to the interaction between both species.

One sustainable alternative to the traditional anthraquinone technology to produce H2O2 is direct H2O2 electrosynthesis by oxygen reduction reaction (ORR). However, selecting electrocatalysts is a great challenge since most of the materials present selectivity towards the formation of H2O (4-electron pathway). In this work, we present a facile electrocatalyst preparation consisting of Ni3TeO6 (NTO), a metal tellurate, mixed with carbon black (Vulcan) with outstanding selectivity (2.2 transferred electrons) towards the production of H2O2 by ORR. To test the possible real application, the NTO/Vulcan catalyst was tested in a long-term stability test showing excellent faradaic efficiency and 93.5 % of the initial current. TEM and XPS measurements after reaction show that NTO/Vulcan materials are robust and durable electrocatalysts. This work opens the door of novel materials such as metal tellurates based on Ni for their application as ORR electrocatalysts in industrial applications.

This work focuses on the development of a new method to utilize deposited coke on zeolite catalysts, formed during the plastic waste cracking. Nitrogen-doped carbon catalysts are prepared using nylon-66 and Zn2+ ion-exchanged ZSM-5 zeolites. After the cracking reaction, nitrogen-doped carbon materials are obtained by removing zeolites from zeolite/coke composites using base and acid treatment. The synthesized N-doped carbon using Zn2+ type ZSM-5 zeolites exhibits higher catalytic performance on the oxygen reduction reaction (ORR) with an onset potential of 0.95 V (vs RHE) and a half-wave potential of 0.80 V (vs RHE) than that using H+ type ZSM-5 zeolites. The characterization revealed that the evaporation of Zn2+ in zeolites significantly enhanced the porosity of N-doped carbon. Moreover, the aromatization and poly-cyclization reactions promoted the generation of highly active edge Valley-N sites, leading to their outstanding activity on ORR. This work provides new directions for the utilization of deposited coke on zeolites.

Currently, the importance of heritage and biocultural memory and, specifically, of traditional and local wisdoms that are expressed in a particular way in legends and other eco-fictions, both in the corpus of folkloric texts and in literary or multimodal texts, is out of the question. There are several paradigms of study, from ecocriticism to other currents, and therefore, the paper aims to make visible the ancestral wisdom in a specific field, which is the imaginary of water, and from a comparative perspective that allows comparing the different discourses alluded to. In particular, we try to explain the animated ecologies through the numenes aquae or personifications/deities of water that are the axis of such ecofictions, looking for patterns and correlations beyond the local context, and relating this humanization of water with the uses and keys symbolic of water culture., Hoy está fuera de discusión la importancia del patrimonio y la memoria biocultural y, en concreto, de las sabidurías tradicionales y locales que se expresan de forma particular en las leyendas y otras ecoficciones (Dwyer, 2010; Martos Núñez, 2013), tanto de corpus de textos folklóricos como de textos literarios o multimodales. Los paradigmas de estudio en que se apoyan dichos estudios son varios, desde la etnoecología a la ecocrítica y otras corrientes críticas, y, por ello, el artículo pretende visibilizar las sabidurías ancestrales en el ámbito de los imaginarios del agua, y desde una perspectiva comparatista en relación a los distintos discursos aludidos. En particular, tratamos de explicar las ecologías animadas a través de los númenes aquae o personificaciones / deidades del agua, que son el eje de tales ecoficciones, buscando patrones y correlaciones más allá del contexto local. Relacionamos esta humanización del agua con los usos y claves simbólicas de la cultura del agua en su diversidad, como es su vinculación con el concepto de habitar poético y con las ecologías animadas.

The interest for the electrodes based on conductive boron-doped diamond powder (BDDP) is increasing in recent years due to their excellent physical and chemical stability, the wide potential window in both aqueous and organic electrolytes, the relatively large specific surface area, and their versatility in comparison to boron-doped diamond thin film electrodes. These materials have been proposed as alternative cathode catalyst support due to their high corrosion resistance when subjected to the highly positive potentials originated during the start-stop operations in fuel cells, especially in automobiles. In this work, we present three BDDP supports with different particle sizes and different surface oxygen contents as supports of different iron species for oxygen reduction reaction in alkaline solution. BDDP supports were modified with carbon nitride (C3N4) or phthalocyanines (Pc) as anchoring points for iron. The different electrocatalytic performance observed confirmed the strong influence of the surface chemistry of the BDDP supports on the activity of the metallic sites for FePc samples while, for Fe-C3N4 samples, the determining effect was the particle size of the BDDP support. Additionally, DFT calculations were used to obtain some insights about the interaction of the FePc with the diamond surface.

Adenosine-5-triphosphate (ATP) is the main energy vector in biological systems, thus its regeneration is an important issue for the application of many enzymes of interest in biocatalysis and synthetic biology. We have developed an electroenzymatic ATP regeneration system consisting in a gold electrode modified with a floating phospholipid bilayer that allows coupling the catalytic activity of two membrane-bound enzymes: NiFeSe hydrogenase from Desulfovibrio vulgaris and F1Fo-ATP synthase from Escherichia coli. Thus, H2 is used as a fuel for producing ATP. This electro-enzymatic assembly is studied as ATP regeneration system of phosphorylation reactions catalysed by kinases, such as hexokinase and NAD+-kinase for respectively producing glucose-6-phosphate and NADP+. © 2023 The Author(s)