Alfonso Sáez | University of Alicante / Universidad de Alicante (original) (raw)
Papers by Alfonso Sáez
Journal of Power Sources, 2021
Abstract The development of clean, renewable, and affordable energy sources such as wind or sun h... more Abstract The development of clean, renewable, and affordable energy sources such as wind or sun has become a necessity for a sustainable energy society. Consequently, it is highly required the development of energy storage systems capable of efficiently storing the energy generated by these intermittent sources. In recent years, hydrogen-based technologies have emerged as a way of mitigating the environmental footprint left by the fossil fuels-based ones. In this paper we report new insights into the performance of an environmentally friendly Acid-Base Electrochemical Flow Battery (ABEFB), using an electrolyte consisting of high NaCl concentration. Energy is obtained from the neutralization of two acid and alkaline solutions through hydrogen evolution and oxidation reactions. Different parameters such as the nature of the cationic membrane and the electrolyte concentration have been systematically evaluated. Under optimal conditions, this battery can provide a maximum power density of about 73.5 W m-2 at 215 A m−2, a coulombic efficiency of around 80%, and a round-trip efficiency of 52%.
La introduccion de las tecnologias de la informacion y comunicacion (TIC) en los campos de la doc... more La introduccion de las tecnologias de la informacion y comunicacion (TIC) en los campos de la docencia e investigacion presenta numerosas ventajas en relacion al fomento de la participacion, el trabajo colaborativo y la cooperacion de los estudiantes de grado, de master o de doctorado. Este trabajo tiene como primer objetivo analizar el impacto de las plataformas online sobre el aprendizaje de los estudiantes y, en segundo lugar, desarrollar alternativas que fomenten la participacion e interaccion de los estudiantes utilizando estas plataformas educativas. Con estos objetivos, esta red educativa ha adquirido durante estos ultimos anos una notable experiencia en la organizacion de congresos online. Sin embargo, todas las potencialidades comunicativas que podria ofrecer un congreso online a sus participantes no han sido todavia exploradas: la incorporacion de las herramientas utilizadas en las redes sociales para promover la participacion de los estudiantes, o bien la posibilidad de q...
Historicamente, los congresos cientificos son, y han sido, uno de los mecanismos mas efectivos pa... more Historicamente, los congresos cientificos son, y han sido, uno de los mecanismos mas efectivos para la difusion y el debate del conocimiento. A pesar de ello, un ambiente altamente formal no es el mas idoneo para que los estudiantes de tercer ciclo saquen el maximo rendimiento, relegandolos a un segundo plano y anulando practicamente su participacion. Con el reto de propiciar la intervencion de los estudiantes de master y doctorado, fundamentalmente a traves de planteamiento de preguntas, se ha organizado y celebrado el I Congreso Online de Jovenes Investigadores en Electroquimica. Enmarcado en los programas interuniversitarios de master y doctorado de �Electroquimica. Ciencia y Tecnologia�, y mediante la herramienta Moodle, los estudiantes han participado en el congreso mediante comunicaciones en formato de poster. Ademas, han podido mantener discusiones cientificas y expresar sus dudas e inquietudes hacia el trabajo de sus companeros. Para implicar al alumno, se han otorgado certi...
RESUMEN Los congresos cientificos son una buena herramienta para que los estudiantes de tercer ci... more RESUMEN Los congresos cientificos son una buena herramienta para que los estudiantes de tercer ciclo puedan ampliar sus conocimientos. Sin embargo, las intervenciones donde los estudiantes plantean dudas o preguntas son practicamente nulas. Con el objetivo de fomentar la participacion de los estudiantes en los congresos cientificos, la nueva red continua con el trabajo anteriormente realizado, llevando a cabo la II edicion del Congreso online de estudiantes dentro del programa interuniversitario “Electroquimica. Ciencia y Tecnologia”. La red busca concienciar acerca de la importancia que para un investigador tiene un congreso cientifico y a su vez, incrementar y mejorar su participacion. Para ello, se utiliza un formato mas atractivo que en la edicion anterior, que mejora el entorno de trabajo y favorece la interaccion entre los estudiantes. Asimismo, se emplean estrategias de comunicacion mas desarrolladas para hacer crecer el numero de participantes. Finalmente, se estableceran di...
Journal of CO2 Utilization, 2017
Electrochemical reduction of CO2 has been pointed out as an interesting strategy to convert CO2 i... more Electrochemical reduction of CO2 has been pointed out as an interesting strategy to convert CO2 into useful chemicals. In addition, coupling CO2 electroreduction with renewable energies would allow storing electricity from intermittent renewable sources such as wind or solar power. In this work, an easy and fast method is adapted for the synthesis of pure and carbon supported Sn nanoparticles. The resulting nanoparticles have been characterized by transmission electron microscopy and their electrocatalytic properties towards CO2 reduction evaluated by cyclic voltammetry. Carbon supported Sn nanoparticles have been subsequently used to prepare Gas Diffusion Electrodes (Sn/C-GDEs). The electrodes have been characterized by scanning electron microscopy and also by cyclic voltammetry. 2 Finally, the electrodes were tested on a continuous and single pass CO2 electroreduction filter-press type cell system in aqueous solution, to obtain formate at ambient pressure and temperature. These Sn/C-GDEs allow working at high current densities with low catholyte flow. Thus, for instance, at 150 mA cm-2 , a 70 % Faradaic Efficiency (FE) was obtained with a formate concentration of 2.5 g L-1. Interestingly, by increasing the current density to 200 mA cm-2 and decreasing the flow rate, a concentration over 16 g L-1 was reached. Despite the high concentrations obtained, further research is still required to keep high FE operating at high current densities.
International Journal of Hydrogen Energy, 2016
In this paper, we present a new Acid-Base Electrochemical Flow Battery (ABEFB). This system is co... more In this paper, we present a new Acid-Base Electrochemical Flow Battery (ABEFB). This system is composed of acidic and alkaline solutions, both with a high supporting electrolyte concentration. These solutions are separated by a 10 proton exchange membrane, using hydrogen as both a reactant and a product. Under this configuration, neutralization energy is used as electromotive force. Thus, in the charging process, hydrogen is oxidized to form hydronium ions (hydrogen oxidation reaction-HOR-) (positive electrode) that acidifies positive electrolyte or posilyte, while hydrogen is formed from water (hydrogen evolution 15 reaction-HER-) (negative electrode) that basifies negative electrolyte or negalyte. On the other hand, during the discharging process, both electrolytes are neutralized through hydrogen oxidation and hydrogen evolution reactions. A platinised titanium electrode is chosen for HER and a platinum-catalysed gas diffusion electrode is used for HOR. This proof of concept has been verified for 20 several charge capacities obtaining a maximum power density of 20 mW cm-2 at 49 mA cm-2. In this sense, faradaic efficiency close to 95 % and energy efficiency of 55 % are also obtained. Finally, the reuse of produced hydrogen is an interesting aspect to be considered.
Journal of Electroanalytical Chemistry, 2017
In this work a new electrocoagulation reactor with cylindrical geometry using a three-dimensional... more In this work a new electrocoagulation reactor with cylindrical geometry using a three-dimensional steel wool anode has been developed. The architecture of the Electrocoagulation reactor is closely related to a filter cartridge, modified in order to contain the electrodes. The complete system includes the Cartridge Type ElectroCoagulation Reactor (CTECR) and its housing. The residence time distribution (RTD) was used as tool to study the flow behavior of the electrolyte within the reactor. The new reactor has been successfully used in the removal of a textile dye (Remazol Red RB 133) working in continuous mode of operation, where the color elimination rate reaches 99 %. Moreover, its design allows both an easy replacement of the cartridge when the steel wool anode is consumed, and the collection and storage of the hydrogen generated on the cathode. Highlights A new Cartridge type reactor for electrocoagulation is tested. Electrocoagulation is performed using 3D electrodes made of steel wool anodes. Removal of textile dye Remazol Red RB 133 is used as test reaction. Color removal efficiency reaches 99%.
El reconocimiento docente: innovar e investigar con criterios de calidad.
Beilstein Journal of Organic Chemistry, 2018
The electrocatalytic hydrogenation of benzophenone was performed at room temperature and atmosphe... more The electrocatalytic hydrogenation of benzophenone was performed at room temperature and atmospheric pressure using a polymer electrolyte membrane electrochemical reactor (PEMER). Palladium (Pd) nanoparticles were synthesised and supported on a carbonaceous matrix (Pd/C) with a 28 wt % of Pd with respect to carbon material. Pd/C was characterised by transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). Cathodes were prepared using Pd electrocatalytic loadings (LPd) of 0.2 and 0.02 mg cm−2. The anode consisted of hydrogen gas diffusion for the electrooxidation of hydrogen gas, and a 117 Nafion exchange membrane acted as a cationic polymer electrolyte membrane. Benzophenone solution was electrochemically hydrogenated in EtOH/water (90/10 v/v) plus 0.1 M H2SO4. Current densities of 10, 15 and 20 mA cm−2 were analysed for the preparative electrochemical hydrogenation of benzophenone and such results led to the highest fractional conversion (XR) of around 30% and ...
Electrochimica Acta, 2013
The use of a solid polymeric electrolyte, spe, is not commonly found in organic electrosynthesis ... more The use of a solid polymeric electrolyte, spe, is not commonly found in organic electrosynthesis despite its inherent advantages such as the possible elimination of the electrolyte entailing simpler purification processes, a smaller sized reactor and lower energetic costs. In order to test if it were possible to use a spe in industrial organic electrosynthesis, we studied the synthesis of 1-phenylethanol through the electrochemical hydrogenation of acetophenone using Pd/C 30 wt% with different loadings as cathode and a hydrogen gas diffusion anode. A Polymer Electrolyte Membrane Electrochemical Reactor, PEMER, with a fuel cell structure was chosen to carry out electrochemical reduction with a view to simplifying an industrial scale-up of the electrochemical process. We studied the influence of current density and cathode catalyst loading on this electroorganic synthesis. Selectivity for 1-phenylethanol was around 90% with only ethylbenzene and hydrogen detected as by-products.
Carbon, 2014
Herein, we explore the immobilization of nickel on various carbon supports and their application ... more Herein, we explore the immobilization of nickel on various carbon supports and their application as electrocatalysts for the oxidation of propargyl alcohol in alkaline medium. In comparison with massive and nanoparticulated nickel electrode systems, Ni-doped nanoporous carbons provided similar propargyl alcohol conversions for very low metallic contents. Nanoparticulated Ni on various carbon supports gave rise to the highest electrocatalytic activity in terms of product selectivity, with a clear dependence on Ni content. The results point to the importance of controlling the dispersion of the Ni phase within the carbon matrix for a full exploitation of the electroactive area of the metal. Additionally, a change in the mechanism of the propargyl alcohol electrooxidation was noted, which seems to be related to the physicochemical properties of the carbon support as well. Thus, the stereoselectivity of the electrooxidative reaction can be controlled by the active nickel content immobilized on the anode, with a preferential oxidation to (Z)-3-(2-propynoxy)-2-propenoic acid with high Ni-loading, and to propiolic acid with low loading of active Ni sites. Moreover, the formation of (E)-3-(2-propynoxy)-2-propenoic acid was discriminatory irrespective of the experimental conditions and Ni loadings on the carbon matrixes.
Applied Energy, 2015
ABSTRACT
Applied Catalysis B: Environmental, 2015
In this study, we examine the performance of Cu2O and Cu2O/ZnO surfaces in a filterpress electroc... more In this study, we examine the performance of Cu2O and Cu2O/ZnO surfaces in a filterpress electrochemical cell for the continuous electroreduction of CO2 into methanol. The electrodes are prepared by airbrushing the metal particles onto a porous carbon paper and then are electrochemically characterized by cyclic voltammetry analyses. Particular emphasis is placed on evaluating and comparing the methanol production and Faradaic efficiencies at different loadings of Cu2O particles (0.5, 1 and 1.8 mg•cm-2), Cu2O/ZnO weight ratios (1:0.5, 1:1 and 1:2) and electrolyte flow rates (1, 2 and 3 ml•min-1 •cm-2). The electrodes including ZnO in their catalytic surface were stable after 5 hours, in contrast with Cu2O-deposited carbon papers that present strong deactivation with time. The maximum methanol formation rate and Faradaic efficiency for Cu2O/ZnO (1:1)-based electrodes at an applied potential of-1.3 V vs. Ag/AgCl were r= 3.17 x 10-5 mol•m-2 •s-1 and FE= 17.7 %, respectively. Consequently, the use of Cu2O-ZnO mixtures may be of application for the continuous electrochemical formation of methanol, although further research is still required in order to develop highly active, selective and stable catalysts for CO2 electroreduction to methanol.
In this work carbon supported Pd nanoparticles were prepared and used as electrocatalysts for for... more In this work carbon supported Pd nanoparticles were prepared and used as electrocatalysts for formic acid electrooxidation fuel cells. The influence of some relevant parameters such as the nominal Pt loading, the Nafion/total solids ratio as well as the Pd loading towards formic acid electrooxidation was evaluated using gold supported catalytic layer electrodes which were prepared using a similar methodology to that employed in the preparation of conventional catalyst coated membranes (CCM). The results obtained show that, for constant Pd loading, the nominal Pd loading and the Nafion percentage on the catalytic layer do not play an important role on the resulting electrocatalytic properties. The main parameter affecting the electrocatalytic activity of the electrodes seems to be the Pd loading, although the resulting activity is not directly proportional to the increased Pd loading. Thus, whereas the Pd loading is multiplied by a factor of 10, the activity is only twice which evidences an important decrease in the Pd utilization. In fact, the results obtained suggest the active layer is the outer one being clearly independent of the catalytic layer thickness. Finally, catalyst coated membranes with Pd catalyst loadings of 0.1, 0.5 and 1.2 mg cm-2 were also tested in a breathing direct formic acid fuel cell.
Revista Española de Cirugía Oral y Maxilofacial, 2004
Infections of the maxillofacial area constitute a frequent entity in the daily practice of the ma... more Infections of the maxillofacial area constitute a frequent entity in the daily practice of the maxillofacial surgeon. When speaking of maxillofacial infection, a wide range of conditions, having a different nature, different etiology, different clinical presentation and seriousness, are included in this definition. They may go from simple cases that are treated as outpatients to entities having important morbidity-mortality that require early and aggressive intrahospital treatment. This type of infections may endanger life either due to the mechanical involvement of the airway, due to the production of toxins or due to dissemination to distant organs by contiguity as well as by hematogenic propagation. Since the introduction of antibiotics, infections that jeopardize life are unusual and are associated with some lower mortality Resumen: Objetivo: Las infecciones del área maxilofacial representan un motivo habitual de consulta para los cirujanos maxilofaciales, siendo las más frecuentes las de origen dental. Estas infecciones son frecuentemente polimicrobianas, por lo que el objetivo del presente estudio ha sido evaluar la eficacia clínica y seguridad de piperacilina-tazobactam en el tratamiento de las infecciones del área maxilofacial. Diseño del estudio: Estudio multicéntrico y prospectivo en donde 79 pacientes con infecciones del área maxilofacial recibieron piperacilinatazobactam como tratamiento antibiótico. Resultados: La evolución clínica de los pacientes fue favorable en un 97,5% de los pacientes y la eficacia microbiológica obtenida al final del tratamiento fue del 96,2%. Se presentaron reacciones adversas en 5 pacientes (6,3%): 2 casos de mareo, 2 de dispepsia y un caso de flebitis. En ningún caso se precisó la discontinuación del fármaco. Conclusiones: La eficacia clínica y microbiológica junto con la escasez de efectos adversos presentados, hace de piperacilina-tazobactam una alternativa eficaz en el manejo de estas infecciones. Palabras clave: infecciones del área maxilofacial-piperacilina-tazobactameficacia clínica-seguridad.
Journal of Power Sources, 2021
Abstract The development of clean, renewable, and affordable energy sources such as wind or sun h... more Abstract The development of clean, renewable, and affordable energy sources such as wind or sun has become a necessity for a sustainable energy society. Consequently, it is highly required the development of energy storage systems capable of efficiently storing the energy generated by these intermittent sources. In recent years, hydrogen-based technologies have emerged as a way of mitigating the environmental footprint left by the fossil fuels-based ones. In this paper we report new insights into the performance of an environmentally friendly Acid-Base Electrochemical Flow Battery (ABEFB), using an electrolyte consisting of high NaCl concentration. Energy is obtained from the neutralization of two acid and alkaline solutions through hydrogen evolution and oxidation reactions. Different parameters such as the nature of the cationic membrane and the electrolyte concentration have been systematically evaluated. Under optimal conditions, this battery can provide a maximum power density of about 73.5 W m-2 at 215 A m−2, a coulombic efficiency of around 80%, and a round-trip efficiency of 52%.
La introduccion de las tecnologias de la informacion y comunicacion (TIC) en los campos de la doc... more La introduccion de las tecnologias de la informacion y comunicacion (TIC) en los campos de la docencia e investigacion presenta numerosas ventajas en relacion al fomento de la participacion, el trabajo colaborativo y la cooperacion de los estudiantes de grado, de master o de doctorado. Este trabajo tiene como primer objetivo analizar el impacto de las plataformas online sobre el aprendizaje de los estudiantes y, en segundo lugar, desarrollar alternativas que fomenten la participacion e interaccion de los estudiantes utilizando estas plataformas educativas. Con estos objetivos, esta red educativa ha adquirido durante estos ultimos anos una notable experiencia en la organizacion de congresos online. Sin embargo, todas las potencialidades comunicativas que podria ofrecer un congreso online a sus participantes no han sido todavia exploradas: la incorporacion de las herramientas utilizadas en las redes sociales para promover la participacion de los estudiantes, o bien la posibilidad de q...
Historicamente, los congresos cientificos son, y han sido, uno de los mecanismos mas efectivos pa... more Historicamente, los congresos cientificos son, y han sido, uno de los mecanismos mas efectivos para la difusion y el debate del conocimiento. A pesar de ello, un ambiente altamente formal no es el mas idoneo para que los estudiantes de tercer ciclo saquen el maximo rendimiento, relegandolos a un segundo plano y anulando practicamente su participacion. Con el reto de propiciar la intervencion de los estudiantes de master y doctorado, fundamentalmente a traves de planteamiento de preguntas, se ha organizado y celebrado el I Congreso Online de Jovenes Investigadores en Electroquimica. Enmarcado en los programas interuniversitarios de master y doctorado de �Electroquimica. Ciencia y Tecnologia�, y mediante la herramienta Moodle, los estudiantes han participado en el congreso mediante comunicaciones en formato de poster. Ademas, han podido mantener discusiones cientificas y expresar sus dudas e inquietudes hacia el trabajo de sus companeros. Para implicar al alumno, se han otorgado certi...
RESUMEN Los congresos cientificos son una buena herramienta para que los estudiantes de tercer ci... more RESUMEN Los congresos cientificos son una buena herramienta para que los estudiantes de tercer ciclo puedan ampliar sus conocimientos. Sin embargo, las intervenciones donde los estudiantes plantean dudas o preguntas son practicamente nulas. Con el objetivo de fomentar la participacion de los estudiantes en los congresos cientificos, la nueva red continua con el trabajo anteriormente realizado, llevando a cabo la II edicion del Congreso online de estudiantes dentro del programa interuniversitario “Electroquimica. Ciencia y Tecnologia”. La red busca concienciar acerca de la importancia que para un investigador tiene un congreso cientifico y a su vez, incrementar y mejorar su participacion. Para ello, se utiliza un formato mas atractivo que en la edicion anterior, que mejora el entorno de trabajo y favorece la interaccion entre los estudiantes. Asimismo, se emplean estrategias de comunicacion mas desarrolladas para hacer crecer el numero de participantes. Finalmente, se estableceran di...
Journal of CO2 Utilization, 2017
Electrochemical reduction of CO2 has been pointed out as an interesting strategy to convert CO2 i... more Electrochemical reduction of CO2 has been pointed out as an interesting strategy to convert CO2 into useful chemicals. In addition, coupling CO2 electroreduction with renewable energies would allow storing electricity from intermittent renewable sources such as wind or solar power. In this work, an easy and fast method is adapted for the synthesis of pure and carbon supported Sn nanoparticles. The resulting nanoparticles have been characterized by transmission electron microscopy and their electrocatalytic properties towards CO2 reduction evaluated by cyclic voltammetry. Carbon supported Sn nanoparticles have been subsequently used to prepare Gas Diffusion Electrodes (Sn/C-GDEs). The electrodes have been characterized by scanning electron microscopy and also by cyclic voltammetry. 2 Finally, the electrodes were tested on a continuous and single pass CO2 electroreduction filter-press type cell system in aqueous solution, to obtain formate at ambient pressure and temperature. These Sn/C-GDEs allow working at high current densities with low catholyte flow. Thus, for instance, at 150 mA cm-2 , a 70 % Faradaic Efficiency (FE) was obtained with a formate concentration of 2.5 g L-1. Interestingly, by increasing the current density to 200 mA cm-2 and decreasing the flow rate, a concentration over 16 g L-1 was reached. Despite the high concentrations obtained, further research is still required to keep high FE operating at high current densities.
International Journal of Hydrogen Energy, 2016
In this paper, we present a new Acid-Base Electrochemical Flow Battery (ABEFB). This system is co... more In this paper, we present a new Acid-Base Electrochemical Flow Battery (ABEFB). This system is composed of acidic and alkaline solutions, both with a high supporting electrolyte concentration. These solutions are separated by a 10 proton exchange membrane, using hydrogen as both a reactant and a product. Under this configuration, neutralization energy is used as electromotive force. Thus, in the charging process, hydrogen is oxidized to form hydronium ions (hydrogen oxidation reaction-HOR-) (positive electrode) that acidifies positive electrolyte or posilyte, while hydrogen is formed from water (hydrogen evolution 15 reaction-HER-) (negative electrode) that basifies negative electrolyte or negalyte. On the other hand, during the discharging process, both electrolytes are neutralized through hydrogen oxidation and hydrogen evolution reactions. A platinised titanium electrode is chosen for HER and a platinum-catalysed gas diffusion electrode is used for HOR. This proof of concept has been verified for 20 several charge capacities obtaining a maximum power density of 20 mW cm-2 at 49 mA cm-2. In this sense, faradaic efficiency close to 95 % and energy efficiency of 55 % are also obtained. Finally, the reuse of produced hydrogen is an interesting aspect to be considered.
Journal of Electroanalytical Chemistry, 2017
In this work a new electrocoagulation reactor with cylindrical geometry using a three-dimensional... more In this work a new electrocoagulation reactor with cylindrical geometry using a three-dimensional steel wool anode has been developed. The architecture of the Electrocoagulation reactor is closely related to a filter cartridge, modified in order to contain the electrodes. The complete system includes the Cartridge Type ElectroCoagulation Reactor (CTECR) and its housing. The residence time distribution (RTD) was used as tool to study the flow behavior of the electrolyte within the reactor. The new reactor has been successfully used in the removal of a textile dye (Remazol Red RB 133) working in continuous mode of operation, where the color elimination rate reaches 99 %. Moreover, its design allows both an easy replacement of the cartridge when the steel wool anode is consumed, and the collection and storage of the hydrogen generated on the cathode. Highlights A new Cartridge type reactor for electrocoagulation is tested. Electrocoagulation is performed using 3D electrodes made of steel wool anodes. Removal of textile dye Remazol Red RB 133 is used as test reaction. Color removal efficiency reaches 99%.
El reconocimiento docente: innovar e investigar con criterios de calidad.
Beilstein Journal of Organic Chemistry, 2018
The electrocatalytic hydrogenation of benzophenone was performed at room temperature and atmosphe... more The electrocatalytic hydrogenation of benzophenone was performed at room temperature and atmospheric pressure using a polymer electrolyte membrane electrochemical reactor (PEMER). Palladium (Pd) nanoparticles were synthesised and supported on a carbonaceous matrix (Pd/C) with a 28 wt % of Pd with respect to carbon material. Pd/C was characterised by transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). Cathodes were prepared using Pd electrocatalytic loadings (LPd) of 0.2 and 0.02 mg cm−2. The anode consisted of hydrogen gas diffusion for the electrooxidation of hydrogen gas, and a 117 Nafion exchange membrane acted as a cationic polymer electrolyte membrane. Benzophenone solution was electrochemically hydrogenated in EtOH/water (90/10 v/v) plus 0.1 M H2SO4. Current densities of 10, 15 and 20 mA cm−2 were analysed for the preparative electrochemical hydrogenation of benzophenone and such results led to the highest fractional conversion (XR) of around 30% and ...
Electrochimica Acta, 2013
The use of a solid polymeric electrolyte, spe, is not commonly found in organic electrosynthesis ... more The use of a solid polymeric electrolyte, spe, is not commonly found in organic electrosynthesis despite its inherent advantages such as the possible elimination of the electrolyte entailing simpler purification processes, a smaller sized reactor and lower energetic costs. In order to test if it were possible to use a spe in industrial organic electrosynthesis, we studied the synthesis of 1-phenylethanol through the electrochemical hydrogenation of acetophenone using Pd/C 30 wt% with different loadings as cathode and a hydrogen gas diffusion anode. A Polymer Electrolyte Membrane Electrochemical Reactor, PEMER, with a fuel cell structure was chosen to carry out electrochemical reduction with a view to simplifying an industrial scale-up of the electrochemical process. We studied the influence of current density and cathode catalyst loading on this electroorganic synthesis. Selectivity for 1-phenylethanol was around 90% with only ethylbenzene and hydrogen detected as by-products.
Carbon, 2014
Herein, we explore the immobilization of nickel on various carbon supports and their application ... more Herein, we explore the immobilization of nickel on various carbon supports and their application as electrocatalysts for the oxidation of propargyl alcohol in alkaline medium. In comparison with massive and nanoparticulated nickel electrode systems, Ni-doped nanoporous carbons provided similar propargyl alcohol conversions for very low metallic contents. Nanoparticulated Ni on various carbon supports gave rise to the highest electrocatalytic activity in terms of product selectivity, with a clear dependence on Ni content. The results point to the importance of controlling the dispersion of the Ni phase within the carbon matrix for a full exploitation of the electroactive area of the metal. Additionally, a change in the mechanism of the propargyl alcohol electrooxidation was noted, which seems to be related to the physicochemical properties of the carbon support as well. Thus, the stereoselectivity of the electrooxidative reaction can be controlled by the active nickel content immobilized on the anode, with a preferential oxidation to (Z)-3-(2-propynoxy)-2-propenoic acid with high Ni-loading, and to propiolic acid with low loading of active Ni sites. Moreover, the formation of (E)-3-(2-propynoxy)-2-propenoic acid was discriminatory irrespective of the experimental conditions and Ni loadings on the carbon matrixes.
Applied Energy, 2015
ABSTRACT
Applied Catalysis B: Environmental, 2015
In this study, we examine the performance of Cu2O and Cu2O/ZnO surfaces in a filterpress electroc... more In this study, we examine the performance of Cu2O and Cu2O/ZnO surfaces in a filterpress electrochemical cell for the continuous electroreduction of CO2 into methanol. The electrodes are prepared by airbrushing the metal particles onto a porous carbon paper and then are electrochemically characterized by cyclic voltammetry analyses. Particular emphasis is placed on evaluating and comparing the methanol production and Faradaic efficiencies at different loadings of Cu2O particles (0.5, 1 and 1.8 mg•cm-2), Cu2O/ZnO weight ratios (1:0.5, 1:1 and 1:2) and electrolyte flow rates (1, 2 and 3 ml•min-1 •cm-2). The electrodes including ZnO in their catalytic surface were stable after 5 hours, in contrast with Cu2O-deposited carbon papers that present strong deactivation with time. The maximum methanol formation rate and Faradaic efficiency for Cu2O/ZnO (1:1)-based electrodes at an applied potential of-1.3 V vs. Ag/AgCl were r= 3.17 x 10-5 mol•m-2 •s-1 and FE= 17.7 %, respectively. Consequently, the use of Cu2O-ZnO mixtures may be of application for the continuous electrochemical formation of methanol, although further research is still required in order to develop highly active, selective and stable catalysts for CO2 electroreduction to methanol.
In this work carbon supported Pd nanoparticles were prepared and used as electrocatalysts for for... more In this work carbon supported Pd nanoparticles were prepared and used as electrocatalysts for formic acid electrooxidation fuel cells. The influence of some relevant parameters such as the nominal Pt loading, the Nafion/total solids ratio as well as the Pd loading towards formic acid electrooxidation was evaluated using gold supported catalytic layer electrodes which were prepared using a similar methodology to that employed in the preparation of conventional catalyst coated membranes (CCM). The results obtained show that, for constant Pd loading, the nominal Pd loading and the Nafion percentage on the catalytic layer do not play an important role on the resulting electrocatalytic properties. The main parameter affecting the electrocatalytic activity of the electrodes seems to be the Pd loading, although the resulting activity is not directly proportional to the increased Pd loading. Thus, whereas the Pd loading is multiplied by a factor of 10, the activity is only twice which evidences an important decrease in the Pd utilization. In fact, the results obtained suggest the active layer is the outer one being clearly independent of the catalytic layer thickness. Finally, catalyst coated membranes with Pd catalyst loadings of 0.1, 0.5 and 1.2 mg cm-2 were also tested in a breathing direct formic acid fuel cell.
Revista Española de Cirugía Oral y Maxilofacial, 2004
Infections of the maxillofacial area constitute a frequent entity in the daily practice of the ma... more Infections of the maxillofacial area constitute a frequent entity in the daily practice of the maxillofacial surgeon. When speaking of maxillofacial infection, a wide range of conditions, having a different nature, different etiology, different clinical presentation and seriousness, are included in this definition. They may go from simple cases that are treated as outpatients to entities having important morbidity-mortality that require early and aggressive intrahospital treatment. This type of infections may endanger life either due to the mechanical involvement of the airway, due to the production of toxins or due to dissemination to distant organs by contiguity as well as by hematogenic propagation. Since the introduction of antibiotics, infections that jeopardize life are unusual and are associated with some lower mortality Resumen: Objetivo: Las infecciones del área maxilofacial representan un motivo habitual de consulta para los cirujanos maxilofaciales, siendo las más frecuentes las de origen dental. Estas infecciones son frecuentemente polimicrobianas, por lo que el objetivo del presente estudio ha sido evaluar la eficacia clínica y seguridad de piperacilina-tazobactam en el tratamiento de las infecciones del área maxilofacial. Diseño del estudio: Estudio multicéntrico y prospectivo en donde 79 pacientes con infecciones del área maxilofacial recibieron piperacilinatazobactam como tratamiento antibiótico. Resultados: La evolución clínica de los pacientes fue favorable en un 97,5% de los pacientes y la eficacia microbiológica obtenida al final del tratamiento fue del 96,2%. Se presentaron reacciones adversas en 5 pacientes (6,3%): 2 casos de mareo, 2 de dispepsia y un caso de flebitis. En ningún caso se precisó la discontinuación del fármaco. Conclusiones: La eficacia clínica y microbiológica junto con la escasez de efectos adversos presentados, hace de piperacilina-tazobactam una alternativa eficaz en el manejo de estas infecciones. Palabras clave: infecciones del área maxilofacial-piperacilina-tazobactameficacia clínica-seguridad.