Tailoring gas-phase CO2 electroreduction selectivity to hydrocarbons at Cu nanoparticles

Copper-based surfaces appear as the most active catalysts for CO2 electroreduction to hydrocarbons, even though formation rates and efficiencies still need to be improved. The aim of the present work is to evaluate the continuous gas-phase CO2 electroreduction to hydrocarbons (i.e. ethylene and methane) at copper nanoparticulated-based surfaces, paying attention to particle size influence (ranging from 25–80 nm) on reaction productivity, selectivity, and Faraday efficiency (FE) for CO2conversion. The effect of the current density and the presence of a microporous layer within the working electrode are then evaluated. Copper-based gas diffusion electrodes are prepared by airbrushing the catalytic ink onto carbon supports, which are then coupled to a cation exchange membrane (Nafion) in a membrane electrode assembly. The results show that the use of smaller copper nanoparticles (25 nm) leads to a higher ethylene production (1148 μmol m−2 s−1) with a remarkable high FE (92.8%), at the same time, diminishing the competitive hydrogen evolution reaction in terms of FE. This work demonstrates the importance of nanoparticle size on reaction selectivity, which may be of help to design enhanced electrocatalytic materials for CO2 valorization to hydrocarbons.The authors gratefully acknowledge the financial support from the Spanish Ministry of Economy and Competitiveness (MINECO) through the projects CTQ2013-48280-C3-1-R and CTQ2016-76231-C2-1-R. Ivan Merino-Garcia and Jonathan Albo would also like to thank the MINECO for the Early Stage Researcher Contract (BES-2014-070081) and Ramón y Cajal programme (RYC-2015-17080), respectively

Referencias corológicas de plantas vasculares en el NW ibérico

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Nuevas aportaciones al Atlas de la Pteridoflora Ibérica y Balear (APIB

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Electrochemical membrane reactors for the utilisation of carbon dioxide

Climate change is among the greatest challenges for humankind in the 21st century. Carbon Capture and Utilisation (CCU) allows the production of value-added chemicals from CO2, reducing at the same time the undesirable effects of global warming. Among the available methods for CO2 utilisation, the electrochemical reduction appears as a promising technological solution to store intermittent renewable energy in the form of chemical bonds, leading to valuable chemicals such as formic acid, methanol or methane, which can be put back into the market. The application of electrochemical membrane reactors (ecMRs) for the valorisation of CO2 allows the separation of the catholyte and anolyte compartments, leading to an enhanced separation of reaction products and avoiding their re-oxidation. Among these membrane-based reactors, the utilisation of Membrane Electrode Assemblies (MEAs), where the cathode and anode are coupled with a conductive membrane, are gaining importance. Besides, gas diffusion electrodes (GDEs) are able to reduce mass transfer limitations and therefore, enhance efficiencies in the process of CO2 electroreduction. Thus, the aim of the present review is to compile the literature on the application of membrane reactors for CO2 electroreduction, paying special attention to the type of membrane, reactor configuration and catalytic material in electrochemical reactors. Then, a performance comparison in terms of Faradaic efficiency for different products reported to date, is carried out.The authors gratefully acknowledge the financial support of the Spanish Ministry of Economy and Competitiveness (MINECO) through the project CTQ2013-48280-C3-1-R. Ivan Merino-Garcia and Jonathan Albo would like also to thank the MINECO for the Early Stage Researcher grant (BES2014-070081) and Juan de la Cierva postdoctoral program (JCI-2012-12073)

Bimetallic Cu-based hollow fibre electrodes for CO2 electroreduction

The electrochemical reduction of CO2 represents an attractive alternative to both, satisfy the increasing energy demand, and to help closing the carbon cycle. However, the energy required for CO2 activation and the subsequent multiple number of proton-coupled electron transfer steps involved, makes this process very challenging. Besides, catalytic material limitations are hampering the application of this technology in the short term. Consequently, in this work we synthesise, characterise and preliminarily evaluate bimetallic Cu-based hollow fibre electrodes with a compact three-dimensional geometry to overcome mass transfer limitations and to enhance the electrochemical conversion of CO2. The Cu hollow fibres are functionalised with Au in an attempt to tune the binding energy of the CO* intermediate, which appears to be key in the reduction of CO2. The Cu fibres are also functionalised with Ni, aiming to decrease the reaction overpotential, resulting in beneficial energy efficiency. The so prepared Cu-based porous hollow fibre electrodes are obtained by spinning and electrodeposition procedures. The materials are then characterised by scanning electron microscopy, energy dispersive X-ray spectroscopy, Xray diffraction analyses and cyclic voltammetry tests. Finally, preliminary results of CO2 electroreduction in a divided three-electrode cell are reported. The results show the potential of highly active, bimetallic hollow fibre-based electrocatalysts for enhanced conversion of CO2 into value-added products, and deposition of particles should be performed with acre, not to effect pore characteristics and thus mass transfer properties.I. M-G would like to thank the Spanish Ministry of Economy and Competitiveness (MINECO) for the Early Stage Researcher Contract, including the Research Stay grant (EEBB-I-17-12382) as well as the postdoctoral period of the predoctoral contract (BES-2014-070081). I. M-G, J. A and A. I gratefully acknowledge financial support from the MINECO through the projects CTQ2013-48280-C3-1-R and CTQ2016-76231-C2-1-R, as well as Ramón y Cajal programme (RYC-2015-17080). G. M also acknowledges NanoNextNL, a micro and nanotechnology consortium of the Government of the Netherlands and 130 partners

Contrasting crustal sources for peraluminous granites of the segmented Montes de Toledo Batholith (Iberian Variscan Belt)

The Variscan Montes de Toledo Batholith (MTB) is an E–W linear array of peraluminous granite plutons which is chemically segmented. The study is focused on the western segment of the MTB (W-MTB), mainly composed of granites with slightly lower CaO and higher P2O5 contents than associated eastern plutonic units and nearby S-type granites, giving them a more pronounced peraluminous nature. The chemical contrast is also observed in isotopic composition, especially in radiogenic Nd and Pb ratios. The W-MTB granites have higher initial εNd (–5.0 to –5.9) and lower 206Pb/204Pb and 208Pb/204Pb ratios than peraluminous types from the E-MTB segment. A mixed pelitic–greywackeous derivation from regional Neoproterozoic formations is suggested, whereas lower crustal and meta-igneous sources were involved in the origin of the easternmost MTB granites. The presence of igneous muscovite together with coexisting andalusite and sillimanite in some of the studied granites suggests that solidus was reached at 650–700 ºC and depth corresponding to the pressure of 2–3 kbar

Los Rhamnus de la Cordillera Cantábrica (NW de la Península Ibérica)

[ES] Se lleva a cabo un estudio de las especies del género Rhamnus L. presentes en la Cordillera Cantábrica y sus estribaciones, siguiendo las técnicas de la taxonomía numérica. Se propone la nueva combinación Rhamnus L. Sect. Chamaethamnos (Vent) Ma J. López, E. Puente, F. Llamas & A. Penas comb, nova y se aporta una clave para la determinación de los táxones estudiados.[EN] A study of the Rhamnus L. living in the Cantabrian Mountains and near places, by means of numerical taxonomy methods is carried out. It is proposed a new combination Rhamnus L. Sect. Chamaethamnos (Vent) Mâ J. López, ?. Puente, F. Llamas & A. Penas comb. nova. A key for the determination of all these taxa is presented

Competencia social y pragmática en el alumnado inmigrante

El estudio analiza la relación existente entre la competencia pragmática y la competencia social del alumnado inmigrante en la etapa de Educación Primaria, diferenciando entre aspectos facilitadores (liderazgo, jovialidad, sensibilidad social y respeto-autocontrol) y perturbadores/inhibidores (agresividad-terquedad, apatía-retraimiento y ansiedad-timidez) de la socialización. La muestra está compuesta por un total de 326 alumnos de origen inmigrante, de edades comprendidas entre los 6 y los 12 años escolarizados en colegios públicos. El instrumento utilizado para evaluar la socialización de los escolares, es la versión para profesores de la Batería de Socialización (BAS) y utilizamos la versión Screening Revisada de la Batería de Lenguaje Objetiva y Criterial (BLOCSR) para evaluar la competencia pragmática. Los resultados ponen de manifiesto la relación existente entre la competencia pragmática y las dimensiones facilitadoras y perturbadoras de la socialización en el alumnado inmigrante, señalando que los alumnos que dominan la competencia pragmática, muestran altas puntuaciones en liderazgo y a su vez puntúan menos en ansiedad-timidez.The study analyzes the relationship between pragmatic competence and social competence of immigrant students in Primary Education, differentiating between facilitators aspects (leadership, joviality, social sensibility, self-respect) and disruptive / inhibitors (aggressiveness, obstinacy, apathy -withdrawal and anxiety-shyness) socialization. The sample is made up of a total of 326 immigrant students, aged between 6 and 12 years enrolled in public schools. The instrument used to evaluate the socialization of school students is the version for teachers of the Socialization Test (BAS) and we used the Revised Screening version of the Objective Language Criteria Test (BLOC-SR) to evaluate the children’s pragmatic competence. The results show the relationship between pragmatic competence and enabling and disruptive dimensions of socialization in immigrant students, indicating that students who master the pragmatic competence, show high scores in leadership and in turn scored less anxiety-shyness

Análisis de los factores determinantes del precio del activo vivienda

En el presente trabajo se analiza el comportamiento del mercado del activo-vivienda en el periodo 1978-2000 desde la perspectiva de los factores que influyen directamente en la formación de los precios de dicho activo. Los factores que individualmente mejor explican las variaciones en el precio de la vivienda son (por orden decreciente): el IPC corregido, los costes de la construcción, el PIB per capita, el precio de los alquileres, las VPO terminadas, el volumen de crédito disponible, el tipo de interés de referencia, las viviendas libres terminadas y la población en el intervalo 24-35 años. A nivel agregado, el grupo de variables que mejor explican conjuntamente las fluctuaciones del mercado hipotecario son: PIB per capita, el precio del alquiler de la vivienda y los tipos de interés de referencia. Las variables más representativas son tanto de tipo financiero como macroeconómico (estructurales), por lo que se observa que tanto el modelo anglosajón como el germánico explican, parcialmente, el comportamiento inversor en España