Hydrolytic Dehydrogenation of Ammonia Borane Attained by Ru-Based Catalysts: An Auspicious Option to Produce Hydrogen from a Solid Hydrogen Carrier Molecule

Chemical hydrogen storage stands as a promising option to conventional storage methods. There are numerous hydrogen carrier molecules that afford satisfactory hydrogen capacity. Among them, ammonia borane has attracted great interest due to its high hydrogen capacity. Great efforts have been devoted to design and develop suitable catalysts to boost the production of hydrogen from ammonia borane, which is preferably attained by Ru catalysts. The present review summarizes some of the recent Ru-based heterogeneous catalysts applied in the hydrolytic dehydrogenation of ammonia borane, paying particular attention to those supported on carbon materials and oxides.This work was financed by the MICINN, FEDER (RTI2018-095291-B-I00). MNG thanks the Plan GenT project (CDEIGENT/2018/027) for their financial support. DST thanks MICINN for the “Juan de la Cierva” contract (IJCI-2016-27636) and the Vicerrectorado de Investigación y Transferencia de Conocimiento de la Universidad de Alicante (GRE19-16)

Strategies to Enhance the Performance of Electrochemical Capacitors Based on Carbon Materials

The increasing worldwide energy consumption has contributed to both the vast growth of greenhouse emissions from carbon-containing fuels-based sources (coal, petroleum, etc.) and the depletion of the aforementioned sources. Given this scenario, the development of inexpensive and high-performing energy storage devices, which have the least possible environmental impact, is needed. At this point, electrochemical capacitors (ECs) or supercapacitors are a particular alternative or complementary option to batteries and fuel cells (FCs). ECs present high power output and long cycle life, but little power density compared to conventional or Lithium-ion batteries. Therefore, ECs are going to play a pivotal role, not only in portable electronic devices, but also to provide power density in hybrid electric vehicles. Many efforts have been focused on improving the energy output of ECs, although its enhancement keeping the high power density is still the cornerstone of most investigations. Many studies have been conducted toward the development of electrode materials such as metal oxides, conducting polymers or novel carbons. Nevertheless, they have shown important shortcomings to be implemented (i.e., high cost, low electrical conductivity, poor stability, etc.). Recent studies put the spotlight on nitrogen-containing carbon materials as candidates to improve the ECs performance in terms of energy. Optimizing the ECs configuration (asymmetric and hybrid) is another approach reported to tackle the challenge. Additionally, it is important to mention that the design of carbon materials obtained from inexpensive precursors lately attracted the attention of the research community. This review compiles works performed in our research group over the last years. The effect of nitrogen groups present in the carbon network on the capacitance will be reported and the study of asymmetric configuration to enhance de energy density will be discussed, either opening the potential window or by increasing the capacitance. Moreover, a lignin-based ECs will be described as an environmentally friendly approach. Finally, perspective and conceivable research guidelines in order to hurdle the challenges proposed to implement the carbon materials in the field of ECs will be addressed.We want to acknowledge the financial support by the Ministry of Economy and Competitiveness of Spain (MINECO) and FEDER (CTQ2015-66080-R MINECO/FEDER and MAT2016-76595-R)

Método POGIL para el Aprendizaje Cooperativo en Ciencias: Aplicación a la asignatura “Oceanografía Química”

Se muestra un método de aprendizaje cooperativo para una asignatura del Grado de Ciencias del Mar donde se aplica el método POGIL (Process-Oriented Guided Inquiry Learning). Los estudiantes aprenden los temas del curso siguiendo el ciclo del aprendizaje. En cada actividad se muestra un experimento o caso de estudio y se realizan preguntas para guiar a la comprensión del fenómeno observado. Tras la discusión y adquisición de los nuevos conceptos se formulan ejercicios para la aplicación de los mismos. Los grupos aprenden de forma autónoma pero el diseño de la actividad, menos libre que en métodos de aprendizaje similares (como el Aprendizaje Basado en Problemas) asegura la consecución de las competencias de conocimiento al final de la actividad. Se desarrollan además competencias genéricas: trabajo en equipo, comunicación efectiva y aprendizaje autónomo, entre otras. Se muestra un ejemplo de asignatura casi completamente desarrollada con este formato durante los 3 últimos cursos académicos. Se han realizado encuestas entre los alumnos con el fin de valorar el método educativo observándose que los alumnos se sienten más comprometidos con la asignatura y que tienen una mejor compresión de conceptos de química con este método que con clases tradicionales

Upper gastrointestinal bleeding, an unusual presentation of Rapunzel syndrome

U djece, gastrointestinalni bezoari su općenito sačinjeni od kose i ostataka hrane i imaju neuobičajenu kliničku prezentaciju sa simp- tomima uglavnom kao posljedica opstrukcije gornjeg gastrointestinalnog trakta. U manjem broju pacijenata bezoari se mogu pro- tezati u dvanaesnik, jejunum, ileum pa čak i u debelo crijevo , dajući izgled „Zlatokosinog repa”. Prikazujemo slučaj 7-godišnje djevojčice s atipičnom inicijalnom prezentacijom Zlatokosinog sindroma, kao posljedica trihobe- zoara. Pacijentica nije imala anamnezu pozitivnu na psihijatrijske bolesti, niti prijave bilo kakvih smetnji u školi. Primljena je na hitnu pomoć zbog krvarenja iz gornjeg dijela probavnog sustava te joj je bila potrebna naknadna transfuzija krvnih pripravaka. Tijekom hospitalizacije učinjena je endoskopija gornjeg probavnog trakta s dijagnozom Zlatokosinog sindroma, uz postojanje dva Forrest II-C, III želučana ulkusa i teškog eritematoznog gastritisa u predjelu antruma i tijela. Započeto je konzervativno liječenje, koje je bilo bezuspješno, zbog čega je bezoar morao biti kirurški odstranjen. Stoga želimo ukazati na važnost produbljivanja određenih aspeka- ta kao što su anamneza s naglaskom na psihijatrijsku pozadinu kod ove vrste pacijenata, budući da se radi o poremećaju pove- zanom s promjenama u ponašanju i raspoloženju. Isto tako, važno je imati na umu rjeđe simptoma kao što je krvarenje iz gornjeg dijela probavnog sustava, ali koji pak može biti smrtonosno ako ne djelujemo odmah. Na isti je način sveobuhvatan pristup uz podršku obitelji i intervenciju psihologa i/ili psihijatra od vitalnog značaja za sprječavanje recidiva.Gastrointestinal bezoars in the pediatric age group have an unusual presentation, and their clinical manifestation is mainly associ- ated with obstructive conditions of the gastrointestinal tract, and are generally made up of hair and food debris. In a smaller num- ber, it has been seen that from its usual location, which is the stomach, bezoar structures could extend into the duodenum, jejunum, ileum, and even colon, giving the appearance of a “Rapunzel tail”. We present the case of a 7-year-old girl with an atypical initial presentation of Rapunzel syndrome, secondary to a trichobezoar. The patient did not have previous psychiatric history, nor reports of any disturbance at school. She was admitted to the emergency room due to upper gastrointestinal bleeding and required a subsequent transfusion of blood products. During her hospitalization, an up- per digestive endoscopy was performed, with the diagnosis of Rapunzel syndrome, in addition to the presence of two Forrest II-C, III gastric ulcers and severe erythematous gastritis in the region of the antrum and body. Medical treatment was started without suc- cess, for which the bezoar had to be surgically removed. Therefore, we want to point out the importance of deepening certain aspects such as the medical history and background in this type of patient, since it is a disorder linked to behavioral and mood alterations; likewise, remember the less frequent clinical symp- toms such as upper gastrointestinal bleeding, but which in turn can be lethal if we don’t act promptly. In the same way, the compre- hensive approach with the support of the family and the intervention of psychology and/or psychiatry is vital to prevent recurrences

Photocatalytic Approaches for Hydrogen Production via Formic Acid Decomposition

The photocatalytic dehydrogenation of formic acid has recently emerged as an outstanding alternative to the traditional thermal catalysts widely applied in this reaction. The utilization of photocatalytic processes for the production of hydrogen is an appealing strategy that perfectly matches with the idea of a green and sustainable future energy scenario. However, it sounds easier than it is, and great efforts have been needed to design and develop highly efficient photocatalysts for the production of hydrogen from formic acid. In this work, some of the most representative strategies adopted for this application are reviewed, paying particular attention to systems based on TiO2, CdS and C3N4.The present work was supported by JST, PRESTO (JPMJPR1544) and by Grants-in-Aid for Scientific Research (nos. 26220911, 25289289, and 26630409, 26620194) from the Japan Society for the Promotion of Science (JSPS) and MEXT and “Elemental Strategy Initiative to Form Core Research Center”. MNG gratefully acknowledge the financial support by the Generalitat Valenciana and Plan GenT (CDEIGENT/2018/027) for the financial support. DST thanks MICINN for a “Juan de la Cierva” contract (IJCI-2016-27636)

Electrofluorochromism of Conjugated Polymers Applied to the Development of Chemical Sensors

Electrofluorochromism (EFC) is a phenomenon widely employed for the development of optoelectronic devices. In this work, we applied EFC as a powerful tool in sensing applications. The ability to tune the photoluminescence emission by controlling the applied potential may help maximize the response to target molecules. We have explored the EFC of the conjugated copolymer poly[9,9-dioctylfluorene-alt-benzothiadiazole] (F8BT) to design an electrofluorochromic sensor able to detect emerging pollutants with a significant impact in the marine ecosystems. In particular, a sulfonic acid-based chemical sunscreen (Ecamsule) was used as a model molecule. The photoluminescence emission modulation is affected by the presence of Ecamsule, which is attributed to the enhanced quenching process of F8BT during the p-doping process. The quenching is due to the formation of exciplex-like within the conjugated film upon the insertion of the organic anionic molecule in the polymer chain. The developed F8BT-based electrofluorochromic sensor displays a low limit of detection and good selectivity in the presence of interfering anions that are common in seawater.The authors thank the Spanish Ministerio de Ciencia e Innovación (TED2021-129894B–I00 and PDC2021-120884-I00 projects) and Generalitat Valenciana (THINKINAZUL/2021/014, MFA/2022/058 and CIPROM/2021/62 projects) for financial support

Asymmetric hybrid capacitors based on activated carbon and activated carbon fibre–PANI electrodes

Composites consisting of polyaniline (PANI) coatings inside the microporosity of an activated carbon fibre (ACF) were prepared by electrochemical and chemical methods. Electrochemical characterization of both composites points out that the electrodes with polyaniline show a higher capacitance than the pristine porous carbon electrode. These materials have been used to develop an asymmetric capacitor based on activated carbon (AC) as negative electrode and an ACF–PANI composite as positive electrode in H2SO4 solution as electrolyte. The presence of a thin layer of polyaniline inside the porosity of the activated carbon fibres avoids the oxidation of the carbon material and the oxygen evolution reaction is produced at more positive potentials. This capacitor was tested in a maximum cell voltage of 1.6 V and exhibited high energy densities, calculated for the unpackaged active materials, with values of 20 W h kg−1 and power densities of 2.1 kW kg−1 with excellent cycle lifetime (90% during the first 1000 cycles) and high coulombic efficiency.Financial support by the Ministerio de Ciencia e Innovación (MAT2010-15273 and CTQ2009-10813) and Generalitat Valenciana and FEDER (PROMETEO/2009/047 and ACOMP/2012/133) projects are gratefully acknowledged. J.M.S. thanks Ministerio de Educación (SB2010-132). D.S.T. thanks Ministerio de Ciencia e Innovación (BES-2010-035238)

H2 Production from Formic Acid Using Highly Stable Carbon-Supported Pd-Based Catalysts Derived from Soft-Biomass Residues: Effect of Heat Treatment and Functionalization of the Carbon Support

The production of hydrogen from liquid organic hydrogen carrier molecules stands up as a promising option over the conventional hydrogen storage methods. In this study, we explore the potential of formic acid as a convenient hydrogen carrier. For that, soft-biomass-derived carbon-supported Pd catalysts were synthesized by a H3PO4-assisted hydrothermal carbonization method. To assess the impact of the properties of the support in the catalytic performance towards the dehydrogenation of formic acid, three different strategies were employed: (i) incorporation of nitrogen functional groups; (ii) modification of the surface chemistry by performing a thermal treatment at high temperatures (i.e., 900 °C); and (iii) combination on both thermal treatment and nitrogen functionalization. It was observed that the modification of the carbon support with these strategies resulted in catalysts with enhanced performance and outstanding stability even after six consecutive reaction cycles, thus highlighting the important effect of tailoring the properties of the support.This work was financed by the MICINN, FEDER (RTI2018-095291-B-I00). J.C.-G. is grateful for her pre-doctoral scholarship (GRISOLIA/2018/105), funded by the Generalitat Valenciana. M.N.-G. would like to thank the Plan GenT project (CDEIGENT/2018/027) for their financial support. D.S.-T. thanks Vicerrectorado de Investigación y Transferencia de Conocimiento de la Universidad de Alicante for their financial support (GRE19-16)

Highly Stable N-Doped Carbon-Supported Pd-Based Catalysts Prepared from Biomass Waste for H2 Production from Formic Acid

Excellent Pd supported on carbon catalysts for the dehydrogenation of formic acid were synthesized from a lignocellulosic biomass residue. The preparation of the carbon support consisted of a H3PO4-assisted hydrothermal carbonization (HTC) and activation of a hemp residue and subsequent nitrogen functionalization. It was observed that the presence of nitrogen groups influenced both the size and the electronic properties of the Pd nanoparticles, which ultimately affected their catalytic properties. Furthermore, the catalytic performance also depended on the synthesis conditions used in the preparation of the catalysts (i.e., reduction of the Pd nanoparticles with NaBH4 prior to the catalytic test or in situ reduction). The best-performance catalysts (Pd/N-HTC (n.r.)), which were prepared by in situ reduction of the nanoparticles, displayed a remarkable catalytic activity with a very high TOF number of 8365 h–1 (TOF value calculated for the 2nd catalytic run and expressed per surface Pd atom) and outstanding stability during 6 consecutive reaction cycles, although the initial activity is maintained for 12 cycles. The catalytic system studied is among the most stable ever reported Pd-based heterogeneous catalysts for the dehydrogenation of formic acid.This work was financed by the MICINN, FEDER (RTI2018-095291-B-I00). J.C.-G. acknowledges her predoctoral scholarship (GRISOLIA/2018/105) funded by the Generalitat Valenciana. M.N.-G. thanks the Plan GenT project (CDEIGENT/2018/027) for the financial support. D.S.-T. thanks the MICINN for the “Juan de la Cierva” contract (IJCI-2016-27636)