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Abstract Electrochemical carbon dioxide (CO2) conversion to hydrocarbon fuels, such as methane (CH4), offers a promising solution for the long-term and large-scale storage of renewable electricity. To enable this technology, CO2-to-CH4 conversion must achieve high selectivity and energy efficiency at high currents. Here, we report an electrochemical conversion system that features proton-bicarbonate-CO2 mass transport management coupled with an in-situ copper (Cu) activation strategy to achieve high CH4 selectivity at high currents. We find that open matrix Cu electrodes sustain sufficient local CO2 concentration by combining both dissolved CO2 and in-situ generated CO2 from the bicarbonate. In-situ Cu activation through alternating current operation renders and maintains the catalyst highly selective towards CH4. The combination of these strategies leads to CH4 Faradaic efficiencies of over 70% in a wide current density range (100 – 750 mA cm-2) that is stable for at least 12 h at a current density of 500 mA cm-2. The system also delivers a CH4 concentration of 23.5% in the gas product stream.

En este trabajo se describen tres tipos de yacimientos de Fe-Mn en la Sierra del Cuera (Cordillera Cantábrica, NO de España): Sedimentarios (Carbonífero), hidrotermales de baja temperatura (Pérmico inferior) y supergénicos kársticos (Cuaternario). Se han analizado las interrelaciones entre estos yacimientos, determinando su evolución temporal: los yacimientos sedimentarios fueron los primeros en generarse. Posteriormente, el Fe-Mn fue removilizado por un evento hidrotermal y, finalmente, reconcentrado por procesos kársticos recientes.

While water electrolysis devices represent a technology for renewable energy, there are few stable catalysts that survive the acidic conditions. Here, authors enhance acidic oxygen evolution by introducing strong Brønsted acid sites into RuO2 to accelerate bridging-oxygen-assisted deprotonation.

En el contexto de la ingente obra legislativa de la Transición política española, la regulación del Patrimonio Real o Patrimonio de la Corona, hoy llamado Patrimonio Nacional, fue un mandato de la Constitución de 1978 que quedó relegado ante la necesidad de hacer frente a cuestiones políticas y económicas más acuciantes, y que sólo se abordó en el último momento, casi al final de la i legislatura de las Cortes Generales. La Ley de 16 de junio de 1982, que finalmente se aprobó, contó con el respaldo unánime de prácticamente todos los grupos del arco parlamentario. La literatura científica se ha ocupado de este tema de forma monográfica en varias ocasiones. Con posterioridad a la Ley de 1982 existen varias publicaciones destacables, que analizan distintos aspectos del régimen jurídico de estos bienes. Falta, sin embargo, un trabajo que dé cuenta del proceso de elaboración y tramitación parlamentaria de la Ley de 1982. Es esta, efectivamente, una pequeña historia de nuestra Transición política que merece ser recuperada por muchas razones. El hecho de que fuese aprobada con un amplio consenso permitió dejar sentadas las bases del régimen jurídico de estos bienes para mucho tiempo, dejándolos fuera de los vaivenes políticos y las alternancias en el poder.

© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Electrochemical carbon dioxide reduction (CO2) is a promising technology to use renewable electricity to convert CO2 into valuable carbon-based products. For commercial-scale applications, however, the productivity and selectivity toward multi-carbon products must be enhanced. A facile surface reconstruction approach that enables tuning of CO2-reduction selectivity toward C2+ products on a copper-chloride (CuCl)-derived catalyst is reported here. Using a novel wet-oxidation process, both the oxidation state and morphology of Cu surface are controlled, providing uniformity of the electrode morphology and abundant surface active sites. The Cu surface is partially oxidized to form an initial Cu (I) chloride layer which is subsequently converted to a Cu (I) oxide surface. High C2+ selectivity on these catalysts are demonstrated in an H-cell configuration, in which 73% Faradaic efficiency (FE) for C2+ products is reached with 56% FE for ethylene (C2H4) and overall current density of 17 mA cm-2. Thereafter, the method into a flow-cell configuration is translated, which allows operation in a highly alkaline medium for complete suppression of CH4 production. A record C2+ FE of ≈84% and a half-cell power conversion efficiency of 50% at a partial current density of 336 mA cm-2 using the reconstructed Cu catalyst are reported.

Stable electrochemical reduction to formate is still challenging. Here, the authors demonstrate a redox-modulation and active-site stabilization strategy for CO2 to formate conversion over 100 days of continuous operation at 100 mA/cm2 with a cathodic energy efficiency of 70%.

Electrochemical reduction of carbon dioxide (CO2RR) to formate provides an avenue to the synthesis of value-added carbon-based fuels and feedstocks powered using renewable electricity. Here, we hypothesized that the presence of sulfur atoms in the catalyst surface could promote undercoordinated sites, and thereby improve the electrochemical reduction of CO2 to formate. We explored, using density functional theory, how the incorporation of sulfur into tin may favor formate generation. We used atomic layer deposition of SnSx followed by a reduction process to synthesize sulfur-modulated tin (Sn(S)) catalysts. X-ray absorption near-edge structure (XANES) studies reveal higher oxidation states in Sn(S) compared with that of tin in Sn nanoparticles. Sn(S)/Au accelerates CO2RR at geometric current densities of 55 mA cm−2 at −0.75 V versus reversible hydrogen electrode with a Faradaic efficiency of 93%. Furthermore, Sn(S) catalysts show excellent stability without deactivation (

The realisation of film made up of different compositions using colloidal QD inks remains a challenge because of redispersing of underlying films by polar solvents. Here, the authors introduce aromatic ligands to achieve QD inks in weakly-polar solvents that enable fabrication of multi-compositional films.

Metal-halide perovskite based tandem solar cells are appealing but making a high efficiency device is not trivial. Here Chen et al. increase the carrier collection in the perovskite layer and largely enhance the efficiency in tandem cells when combined with colloidal quantum dot or silicon layers.