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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 present contribution describes an electrochemical system for the detection of alkaline phosphatase (ALP) enzyme inhibitors in seawater medium. Fluorescence spectroscopy and thermal unfolding results suggest that the state of free ALP is affected in this medium, yet the protein remains active. The enzyme activity can be evaluated using hydroquinone diphosphate as the substrate, with hydroquinone as the electrochemically monitored product. It has been demonstrated that encapsulation in conventional and organic modified silica matrices maintains ALP integrity, although diffusion across the formed monoliths hinders the electrochemical response. ALP@Phenyl-modified silica exhibits the best performance due to higher affinity between substrate molecules and aromatic moieties and, probably, to larger pore size. This electrochemical system can detect and quantify calyculin A in seawater at sub-nanomolar concentrations and it can also be employed for the development of electrochemical biosensors tailored for the marine environment.

Pt nanoparticles were incorporated on carbon black (Vulcan XC-72R) and an activated carbon (F400) using a fast and efficient microwave method. For the preparation, a Pt solution was contacted with the corresponding carbon sample and heated up to 110°C in a microwave oven using an optimised heating rate. TEM images revealed that the carbon-supported Pt nanoparticles had a small average particle size and high dispersion. These Pt-based electrocatalysts showed both high electrocatalytic activity and selectivity towards the 4-electron pathway for the oxygen reduction reaction (ORR) in acid and alkaline media. In addition, they presented excellent stability and resistance to CO poisoning. Moreover, the as-prepared electrocatalysts exhibited outstanding electrocatalytic behaviour for the hydrogen evolution reaction (HER). It should be highlighted that, even though our Pt-based electrocatalysts have much lower loadings than that of the commercial Pt/C sample (used as reference), the electroactive surface areas of as-prepared electrocatalysts were higher compared to the reference electrocatalyst. Such small and well-dispersed Pt NPs with an enhanced electroactive surface area and strong interaction with the carbon support, led to an improvement of the current density normalised by Pt loading (A gPt−1).

La experiencia docente descrita en este trabajo trata sobre el aprendizaje asíncrono sobre medio ambiente y energías sostenibles mediante el uso de una herramienta en línea. Para llevar a cabo dicha experiencia, se preparó un curso mediante la plataforma Moodle, el cual estaba dividido en 4 bloques temáticos ((I) El Cambio Climático: Una Realidad Cotidiana; (II) Energías Sostenibles; (III) Almacenamiento de Energía Sostenible; (IV) El Camino hacia la Sostenibilidad), cada uno de los cuales estaba formado por una serie de diapositivas con el contenido teórico, acompañado de una introducción audiovisual y material complementario que permitía al alumnado profundizar en los temas abordados. Además, al final del curso el alumnado debía contestar a un cuestionario sobre el contenido teórico del mismo y a una encuesta que recababa su opinión sobre el empleo de entornos de aprendizaje virtual asíncrono. Los resultados obtenidos pusieron de manifiesto el interés del alumnado por el empleo de dichos entornos de aprendizaje y el gran potencial de los mismos, los cuales están en línea con los intereses de las nuevas generaciones.

Formic acid has been postulated as one of the most promising liquid organic hydrogen carriers. Numerous studies dealing with the development of efficient catalysts able to boost the dehydrogenation of formic acid can be found in recent literature. However, most of them lack in stability, so that finding stable catalysts is highly desirable yet challenging. In the present study, we developed Pd-based biomass-derived carbon-supported catalysts by following a simple protocol. The effect of the modification of both the metal phase and support has been assessed by incorporating Ag in the form of bimetallic nanoparticles and nitrogen functional groups, respectively. The effect of the method followed for the preparation of the catalysts was also checked. It has been found that the resulting PdAg-based catalysts supported on N-doped biomass-derived carbon materials showed suitable activity and excellent stability under reaction conditions. The present study highlights the potential of modulating the features of the catalysts, not only in terms of the composition of the metal phase and incorporation of heteroatoms in the support, but also in terms of the synthetic protocol used.

In this study, we synthesized MnFe2O4 solid nanospheres (MSN) calcined at different temperatures (200–500 °C) and MSN-based materials mixed with carbon black, for their use as electrocatalysts in the oxygen reduction reaction (ORR) in alkaline medium (0.1 M KOH). It was demonstrated that the calcination temperature of MSN material determined its chemical surface composition and microstructure and it had an important effect on the electrocatalytic properties for ORR, which in turn was reflected in the performance of MSN/CB-based electrocatalysts. The study revealed that the presence of Mn species plays a key role in the ORR activity. Among tested, MSN200/CB and MSN350/CB exhibited the best electrochemical performances together with outstanding stability.

Firstly, Polyaniline-derived@poly(styrene sulfonate) (PANI-derived@PSS) hydrogel materials have been prepared by supramolecular self-assembly between positively charged poly(aniline-co-piperazine) (poly(Ani-co-Pip) chain and negatively-charged PSS chain by oxidative polymerization method. The study of the monomer ratio (X) (aniline:piperazine) has been analyzed. Afterwards, symmetric capacitors based on poly(ANI-co-Pip)@PSS-X mixed with Vulcan (Vu) have been studied. A combination of different techniques like cyclic voltammetry, Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), and Thermogravimetric analyses (TGA) were applied to characterize both the chemical structure and the behavior of the hydrogels. The different hydrogels have exhibited electrical conductivity and electroactivity in acid conditions. Moreover, the effects of Vulcan on the structure and properties of poly(ANI-co-Pip)@PSS have been investigated. Additionally, supercapacitors based on as-prepared poly(ANI-co-Pip)/Vu@PSS displayed an improvement of capacitor performance compare to that of conventional hydrogels-based capacitors. This study offers valuable hints for achieving the preparation of supramolecular materials.

La experiencia docente desarrollada en este trabajo se basa en la utilización de entornos de aprendizaje virtual en asignaturas del área de Química Inorgánica. Dichos entornos de aprendizaje virtual son una herramienta muy útil para afianzar los conceptos y conocimiento adquiridos durante las clases teóricas y experimentales. El empleo de dichos entornos de aprendizaje ha servido para fomentar el interés de las nuevas generaciones de personas científicas haciendo uso de las Tecnologías del Aprendizaje y el Conocimiento (TAC). En la presente experiencia docente se ha empleado la plataforma desarrollada por la empresa Labster, la cual ofrece un amplio catálogo con experiencias de laboratorio virtual relacionadas con temas generales abordados en los laboratorios de química. En esta experiencia docente se ha empleado dicho entorno de aprendizaje en forma de laboratorio virtual a modo de complemento de las clases prácticas que se imparten en la asignatura de Experimentación en Química Inorgánica, del tercer curso del Grado de Química de la Universidad de Alicante. La experiencia docente se evaluó mediante una encuesta preparada con Google Forms y los resultados han puesto de manifiesto que el alumnado muestra gran motivación por el empleo de entornos de aprendizaje online.

Life Cycle Assessment (LCA) is applied to eco-design the H3PO4-assisted hydrothermal carbonization (HTC) process converting biomass residue into high-value products. The main innovation of the process relies on the combination of the H3PO4-assisted HTC with the activation treatment of the obtained hydrochar, resulting in activated carbon that is then functionalized. In addition, the liquid phase obtained from HTC is eventually purified to extract levulinic acid. Under average conditions at the laboratory scale (reference), the LCA showed that electricity consumption is the main contributor (45–70%) to impacts on climate change, photochemical ozone formation, acidification, freshwater eutrophication, freshwater ecotoxicity and fossil resources use. Pyridine, the main chemical used in the functionalization stage, contributes to impacts on human toxicity and on marine eutrophication respectively by 77.3% and 47.3%. Building on these results, two further scenarios were studied, one considering the maximum capacity of each equipment and another one assuming the potential improvements once the process will be upscaled. The scenarios were validated in a series of laboratory scale tests. Depending on the environmental impact category chosen, the results showed a reduction potential of 30–65% as compared to the reference scenario. These findings confirm the added value of LCA in the ecodesign of technologies and pave the way to further improvements of the technology itself but also of the LCA methodology used for the assessment.

La estrategia de aprendizaje en la que se ha centrado este trabajo es el método POGIL (Process Oriented Guided Inquiry Learning), el cual está orientado a mejorar el trabajo del alumnado en grupo haciendo uso de diferentes roles participativos. Este método de carácter cooperativo se aplicó en diferentes asignaturas impartidas en la Facultad de Ciencias, tanto de grado como de postgrado, obteniendo resultados que reflejan la aceptación del método POGIL por parte del alumnado y una mejora en la adquisición de los conceptos en comparación con las clases tradicionales. En esta experiencia se ha planteado el desafío de implementar este método en clases en formato no presencial (online), ya que la situación sanitaria acaecida ha limitado la asistencia del alumnado. A partir de las encuestas realizadas por el alumnado y comparando con los resultados de las encuestas de años anteriores, se puede afirmar que este método se ha aplicado de manera satisfactoria tanto en clases presenciales como en clases online. Adicionalmente, se observó que el contraste entre clases POGIL online y las clases expositivas clásicas es aún mayor que en años anteriores cuando se aplicaba el método POGIL en clases presenciales.

La experiencia docente desarrollada a lo largo de este proyecto de investigación docente está centrada en profundizar sobre los objetivos desarrollados en la red anterior (Lab-on-a-Screen) mediante (1) la mejora y expansión de una herramienta online gracias a la cual el alumnado pueda, de forma lúdica, adquirir conocimientos y destrezas sobre el material de laboratorio y su clasificación, así como de algunas operaciones básicas de laboratorio de Química Inorgánica mediante “e-learning” y (2) posibilitar la inmersión del alumnado en el entorno de laboratorio para mejorar su comprensión y manejo del mismo mediante la grabación de videos didácticos y la construcción de entornos de realidad virtual. La aplicación está vinculada al Campus Virtual de la Universidad de Alicante y cuenta con cuatro actividades principales, que recogen tres experiencias básicas de laboratorio de Química Inorgánica (i.e. destilación, calentamiento a reflujo y destilación a vacío) y una cuarta actividad de carácter más general, que consiste en identificar correctamente material de laboratorio.

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.

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.

Copper ferrite nanospheres (CFNS) were prepared by a solvothermal method and they were calcined at different temperatures ranging from 200−600 °C, resulting in CFNS-based materials with different both surface chemistry and structural features, which play a crucial role in the electrocatalytic activity of carbon black-containing CFNS catalysts towards the oxygen reduction reaction (ORR). The study was addressed to elucidate which kind of crystalline phases, as well as surface chemistry of CFNS were responsible for enhancing the electrocatalytic activity in ORR. The pristine CFNS and CFNS200 (calcined at 200 °C) exhibited cubic spinel, cuprite and copper as main crystalline phases. In the case of CFNS400, it also displays the cubic phase along with a new phase (tenorite). Apart from the tenorite, CFNS600 exhibited hematite, and the cubic phase of spinel shifted to the tetragonal phase. Regarding the electrocatalytic activity in ORR, the CFNS revealed poor activities compared to those of carbon black-containing CFNS catalysts. The high-performing catalyst was CFNS400/Vulcan in terms of current density and onset potential along with its good stability. This improvement may be assigned to both the chemical composition and structure.

High-quality performance of catalysts is increasingly required to meet industry exigencies. However, chemical synthesis is often insufficient to maximize the potential properties of the catalysts. On the other hand, electrochemical synthesis has arisen as a promising alternative to overcome these limitations and provide precise control in the preparation of catalysts. In this sense, this work involved the well-controlled electrochemical synthesis of a catalyst based on platinum nanoparticle deposition on carbon nanotubes using only electrochemical treatments. Thin films of functionalized carbon nanotubes were cast onto the surface of a glassy carbon electrode using potential pulsed electrodeposition, resulting in a better distribution of the carbon nanotubes on the electrode when comparing with traditional methods. Then, platinum nanoparticles were electrodeposited on the carbon nanotube-modified electrode. To check the performance of the catalyst and the relevance of the electrochemical synthesis treatments, the samples were analyzed as electrocatalysts towards methanol electrooxidation, showing an important improvement in the catalytic activity in comparison with electrodes that were prepared by traditional methodologies.

Synthesis of electrode materials for accurate detection and quantification of uric acid without the interference effect of ascorbic acid is still considered an important field for health monitoring in human beings. As we present here, a methodology of composite materials synthesis have been developed to obtain electroactive materials, employing electrochemical methods in a single step based on titanium carbide and titanium dioxide entrapped into a polymer matrix of poly(N-phenyl-o-phenylenediamine). The presence of the TiC and TiO2 nanoparticles entrapped into the polymer matrix has provided enhancement in the conductivity, electron transfer kinetics and electrochemical activity towards uric acid oxidation. The electrochemical behavior of the composite materials towards ascorbic and uric acid oxidation demonstrated that electrochemical oxidation of uric acid has not been affected by the presence of ascorbic acid in solution, being a suitable platform for non-invasive detection and quantification of uric acid concentration in physiological samples without the interference of ascorbic acid.

In this study, we developed Pd nanoparticles-based catalysts supported on composites formed by multi-walled carbon nanotubes (MWCNTs) and graphitic carbon nitride (g-C3N4) in various proportions, for their use in the dehydrogenation of formic acid in the liquid phase. It was observed that the composition of the support determined the average size of the Pd nanoparticles as well as their electronic properties, which ultimately affected the performance of Pd/MWCNT-C3N4 catalysts. Among assessed, the catalyst with 63 wt.% of C3N4 exhibited the best activity, with an initial TOF value of 4258 h-1 calculated based on the surface Pd atoms.

Biomass upgrading is a promising approach to face the current energy consumption and chemicals production. Lignocellulosic biomass residues have taken the lead in this field. In this study, hemp residue-based activated carbons (ACs) were prepared by H3PO4-assisted hydrothermal carbonization (HTC) using a low concentration of H3PO4 (25 wt%). ACs with a high porosity development were obtained (SBET > 1200 m2 g−1), and they were subsequently functionalized with nitrogen groups using mild conditions. As-synthesized ACs were also heat-treated to enhance the electrical conductivity, improving the electrochemical performance. As a proof of concept, electrochemical capacitors (ECs) based on as-prepared ACs in aqueous and organic electrolytes, showing energy densities comparable to those of a capacitor based on an AC used in commercial capacitors. The most attractive outcome of this study is the straightforward, cost-effective, and sustainable methodology to prepare high added-value functional ACs with great potential for energy and environmental applications.

Esta Tesis Doctoral se centra en una metodología innovadora para la síntesis de productos de alto valor añadido (carbón activado) usando como material de partida residuos de biomasa, los cuales son tratados mediante una carbonización hidrotermal asistida con ácido fosfórico (H3PO4) antes del proceso de activación. Con esta metodología se logra disminuir la concentración de agente activante y aumentar el rendimiento del carbón activado. Una vez sintetizados los carbones activados, estos fueron modificados mediante la introducción de grupos funcionales nitrogenados. En primer lugar, los carbones activados fueron usados como electrodos de supercondensadores tanto en electrolito acuoso como en electrolito orgánico, evaluando la influencia de la introducción de nitrógeno en el comportamiento electroquímico de los carbones activados. Posteriormente, se prepararon catalizadores basados en paladio (Pd) usando como soporte los carbones activados sintetizados tanto modificados con nitrógeno como sin modificar y se evaluó el comportamiento catalítico de estos catalizadores en la reacción de deshidrogenación de ácido fórmico para la producción de hidrógeno. Finalmente para demostrar que la metodología implementada para la obtención de carbones activados a partir de residuos de biomasa puede ser considerada como una alternativa sostenible para la obtención de productos de alto valor añadido, se planteó el aprovechamiento no solo de la fase sólida sino también de la fase líquida obtenida de la carbonización hidrotermal para la producción de ácido levulínico. Para esto, se empleó la metodología del análisis del ciclo de vida (LCA, del inglés Life Cycle Assessment) como herramienta para evaluar los impactos ambientales generados en cada etapa del proceso. En general, se logró demostrar las oportunidades que ofrece el aprovechamiento de los residuos de biomasa empleando protocolos de síntesis sencillos y más respetuosos con el medio ambiente para la obtención de productos de alto va