Hydrographic conditions and size-fractionated mesoplankton distribution in the Bay of Biscay shelf during spring

A general description of the hydrography and the distribution of size-fractionated mesoplankton bio-volume in the Bay of Biscay shelf (from 41° up to 47° 30’ N) during spring (April-May) 2005 is presented. Different hydrographic features, such as the Iberian Poleward Current, continental inputs and associated river plumes, thermohaline fronts or the progression of the seasonal thermocline, were noticeable. Mesoplankton biomass was generally low, except in a narrow coastal fringe along the Spanish shelf and in a relatively extensive area in the inner part of the French shelf, where the seasonal thermocline was already established. The size-structure of the mesoplankton community presented a patchy distribution and significant differences between the surface and sub-surface layers of the water column. The size-fractionated distribution of mesoplankton is discussed in the frame of the observed hydrographic structures.SARDYN EU-project (QLRT-2001-00818

Factors involved in soil organic matter stabilization in Peruvian Amazonian soils (Ucayali region) and the molecular composition of extractable lipids

Poster E1012b presentado en el 27th International Meeting on Organic Geochemistry September 13–18, 2015, Prague, Czech RepublicAmazonian ecosystems are considered important sinks for atmospheric CO2 on Earth. It is therefore desirable to preserve their biodiversity and productivity. In this communication an assessment of the influence of different agro-forestry practices on soil C storage in representative ecosystems from the Peruvian Ucayali region is approached by analyzing the soil lipid fraction. In fact, this organic matter fraction is an important source of analytical surrogates of soil C stabilization and accumulation processes (Naafs at al., 2004; Poulenard et al., 2004; Rumpel et al., 2004). Top (0–20 cm) and subsoil (20–40 cm) samples were taken from the Amazonian Ucayali region (Pucallpa, Perú), ranging from recent alluvial soils in muddy zones of riverside areas (wetlands referred to as ‘mud’, ‘beach’ and low ‘restinga’ soils) to more developed soils located in medium and higher riverine terraces, as well as in hills. The lipid fraction was Soxhlet extracted with a mixture of ichloromethane:methanol (2:1 by vol.), saponified and divided into neutral and acid subfractions. The acid fractions were then sequentially methylated and silylated prior to the chromatographic analysis (González-Vila et al., 2003). Neutral and acid sub-fractions were separated and the major compounds were identified by gas chromatography-mass spectrometry using an HP G1800A GCD System (electron impact detector at 70 eV) equipped with a DB-5 fused silica capillary column (30 m × 0.32 mm i.d., film thickness 0.25 µm) and using He as carrier gas at a flow rate of 1.5 mL min-1. The chromatographic oven temperature was programmed to increase from 40 to 100 ºC at 30 ºC min-1 and then to 300 ºC at 6 ºC min -1. The values of soil organic matter and lipids ranged from 25.8 to 5.8 g kg-1, and from 5.2 to 0.2 g kg-1, respectively. This variability as well as the differences in lipid molecular composition could suggest differences in the soils’ use and management practices (Van Bergen et al.,1996). The main families of signature lipids detected in the soil extracts were n-alkanes, linear isoprenoids, cyclic alkanes, n-fatty acids, branched fatty acids, unsaturated fatty acids, hydroxyacids, n-alcohols, ketones, polycyclic hydrocarbons and sterols. Very significant differences in qualitative and quantitative lipid composition were found in terms of soil depth. This effect was more pronounced in the soils from the riverine high terraces devoted to agro-forestry practices (Figs. 1 and 2). In addition, lipidic compounds of high molecular weight (i.e., di- and triterpenes) were detected as regular components of the free lipid fractions from the different ecosystems (wetlands, terraces and hills) reflecting specific vegetation and soil-use influences. Xenobiotic compounds (naphthenic acids) detected within the unresolved chromatographic ‘hump’ (highly unresolved mixture of cyclic or branched hydrocarbons) were also observed, indicating anthropogenic contamination by mineral oils. Likewise, dialkyl phthalates (Phth) from plasticizers were also detected.Projects CGL2012-38655-C04-01 and CGL2008-04296 and fellowship BES-2013-062573 given to N.T.J.M by the Spanish Ministry of Economy and Competitiveness. Dr. J.M.R. is the recipient of a fellowship from the JAE-Doc subprogram financed by the CSIC and the European Social Fund.Peer Reviewe

Prospects of Heterogeneous Hydroformylation with Supported Single Atom Catalysts

[EN] The potential of oxide-supported rhodium single atom catalysts (SACs) for heterogeneous hydroformylation was investigated both theoretically and experimentally. Using high-level domain-based local-pair natural orbital coupled cluster singles doubles with perturbative triples contribution (DLPNO-CCSD(T)) calculations, both stability and catalytic activity were investigated for Rh single atoms on different oxide surfaces. Atomically dispersed, supported Rh catalysts were synthesized on MgO and CeO2. While the CeO2-supported rhodium catalyst is found to be highly active, this is not the case for MgO, most likely due to increased confinement, as determined by extended X-ray absorption fine structure spectroscopy (EXAFS), that diminishes the reactivity of Rh complexes on MgO. This agrees well with our computational investigation, where we find that rhodium carbonyl hydride complexes on flat oxide surfaces such as CeO2(111) have catalytic activities comparable to those of molecular complexes. For a step edge on a MgO(301) surface, however, calculations show a significantly reduced catalytic activity. At the same time, calculations predict that stronger adsorption at the higher coordinated adsorption site leads to a more stable catalyst. Keeping the balance between stability and activity appears to be the main challenge for oxide supported Rh hydroformylation catalysts. In addition to the chemical bonding between rhodium complex and support, the confinement experienced by the active site plays an important role for the catalytic activity.X-ray absorption experiments were performed at the ALBA Synchrotron Light Source (Spain), experiment 2019023278. Beamline scientists L. Simonelli and C. Marini are gratefully acknowledged for their contribution to beam setup. E. Andrés, E. Martínez-Monje, I. López, and M. García-Farpón (ITQ) are acknowledged for their assistance with XAS data acquisition. J. Ternedien (MPI-KOFO) is acknowledged for the performance of XRD experiments. N. Pfänder (MPI-CEC) is acknowledged for his contribution to STEM characterization. The authors acknowledge support by the state of Baden-Württemberg through bwHPC (bwUnicluster and JUSTUS, RV bw17D01). The authors gratefully acknowledge support by the GRK 2450. Financial support from the Helmholtz Association is also gratefully acknowledged. The experimental work received funding from the Max Planck Society and the Spanish Ministry of Science, Innovation and Universities (projects SEV-2016-0683 and RTI2018-096399-A-I00). B.B.S. acknowledges the Alexander von Humboldt Foundation for a postdoctoral scholarship.Amsler, J.; Sarma, BB.; Agostini, G.; Prieto González, G.; Plessow, P.; Studt, F. (2020). 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Surface Lewis Acidity of Periphery Oxide Species as a General Kinetic Descriptor for CO2 Hydrogenation to Methanol on Supported Copper Nanoparticles

[EN] Oxide-supported copper nanoparticles exhibit promising properties as catalysts for the selective hydrogenation of CO2 to methanol. Both reaction rate and selectivity depend conspicuously on the nature of the oxide support/promoter at the metal periphery. However, a major challenge is the achievement of a quantitative description of such metal/oxide promotion effects, which is an essential step toward a rational catalyst design. We investigate structure-performance relationships with a series of model catalysts consisting of Cu nanoparticles dispersed on a mesoporous gamma-Al2O3 carrier overlaid with different transition metal oxides spanning a broad range of Lewis acidity (YOx, ScOx, ZrOx, TaOx). Remarkably, the apparent activation energy (E-a) for methanol formation is found to downscale linearly with the relative Lewis acidity of coordinatively unsaturated metal surface sites (cus) exposed on the oxide support, making this single physicochemical parameter a suitable reactivity descriptor in the whole study space. In correspondence with this performance trend, in situ Fourier transform infrared spectroscopy reveals that both the ionic character and the relative reactivity of bidentate formate species, developed on the catalyst surface under reaction conditions, vary systematically with the surface Lewis acidity of the oxide support. These findings support the involvement of oxide-adsorbed bidentate formate species as reaction intermediates and point to the relative electron-accepting character of the Lewis cus on the oxide surface as the factor determining the stability of these intermediates and the overall energy barrier for the reaction. Our results contribute a unifying and quantitative description for support effects in CO2 hydrogenation to methanol on oxide-supported copper nanoparticles and provide a blueprint for a predictive description of metal-oxide promotion effects, which are ubiquitous in heterogeneous catalysis.The authors are grateful to P. Bussian and Sasol for providing the alumina precursor. S. Ruthe and K. Jeske (MPI-KOFO) are acknowledged for assistance with chromatographic product quantification. J. M. Salas (ITQ) and J. P. Holgado (ICMS-CSIC, Spain) are acknowledged for contributions to the in situ FTIR and XPS experiments, respectively. This research received funding from the Max Planck Society, the Bundesministerium ffir Bildung and Forschung (project 01DG17019), the Spanish Ministry of Science, Innovation and Universities (Severo Ochoa Excellence award SEV-20160683), and the Generalitat Valenciana (Scientific Excellence of Junior Researchers, SEJI2018/011). B.S. acknowledges the Humboldt foundation for a postdoctoral fellowship.Kim, J.; Sarma, BB.; Andres-Marcos, E.; Pfaender, N.; Concepción Heydorn, P.; Prieto González, G. (2019). Surface Lewis Acidity of Periphery Oxide Species as a General Kinetic Descriptor for CO2 Hydrogenation to Methanol on Supported Copper Nanoparticles. ACS Catalysis. 9(11):10409-10417. https://doi.org/10.1021/acscatal.9b02412S104091041791

Interoperabilidad en Sistemas Domóticos Mediante Pasarela Infrarrojos-ZigBee

La domótica consiste en la aplicación de técnicas provenientes de la automática industrial al hogar con objeto de ofrecer servicios que aporten, entre otras cosas, confort, seguridad y eficiencia energética a los usuarios. Hasta el momento la penetración de dichas técnicas en los hogares ha sido reducida. Una de las razones fundamentales de esta lenta transposición de técnicas de control al hogar es la dificultad de integración entre los diferentes sistemas presentes en el hogar. En este artículo se presenta un desarrollo encaminado a mejorar la integración de los sistemas domóticos con aquellos dispositivos que sean controlables mediante infrarrojos. En concreto se ha desarrollado una pasarela inalámbrica que permite a una red domótica el envío de tramas de infrarrojos. De esta manera se posibilita un despliegue rápido y económico de los nodos que sean necesarios para integrar dispositivos tales como los sistemas de aire acondicionado en una red domótica.Ministerio de Industria, Turismo y Comercio MITC-09-TSI-020100-2009-359Ministerio de Educación DPI2008-05818Junta de Andalucía TEP0272