1,721,099 research outputs found
Verso la fotosintesi artificiale: competenze, strutture e progetti di ricerca nel settore
No full textLa fotosintesi artificiale, ovvero la conversione diretta di energia solare in energia chimica attraverso la sintesi fotoindotta di specie
chimiche ad alta energia, quali idrogeno e altri combustibili, a partire da specie a bassa energia come acqua e anidride carbonica, un processo ispirato alla fotosintesi naturale, è stato per lungo tempo un sogno inseguito dalla comunità scientifica internazionale. Gli sviluppi degli ultimi anni permettono adesso di affrontare il problema con buone speranze di successo. L’articolo presenta una breve panoramica delle problematiche relative alla fotosintesi artificiale, delle strutture e dei progetti di ricerca nel settore attualmente presenti nei vari Paesi, con particolare attenzione per gli studi che vengono portati avanti dai ricercatori del SOLAR-CHEM, centro interuniversitario italiano per la conversione chimica dell’energia solare
Design of Functional Electrodes for Novel Photoelectrocatalytic Cells Applied to CO2 Reduction
No full textIn the context of the transition to a low-carbon and sustainable model of economic development, the design of active electrocatalysts for CO2RR is a key step for the development of integrated solutions enabling the carbon-neutral production of chemicals and fuels. DECADE project develops an original PEC (photo-electro-catalytic) approach, using solar energy for the selective conversion of CO2, in combination with bioethanol (or methanol) upgrading. The final aim is to increase energy efficiency and mitigate the current limitation of state-of-the art electrolyzers, based on H2O oxidation as the anodic process. Here, the exploitation of novel multifunctional nanomaterials based on the functionalization of nanocarbon surfaces with active electrocatalysts is of particular interest.
Indeed, the use of metal and metal oxides phases supported on nanocarbon scaffolds reveals good performances for the
electrocatalytic conversion of CO2 in the presence of different electrolytes
Transfer Hydrogenation Catalysis by a N-Heterocyclic Carbene (NHC) Iridium Complex on a Polyoxometalate Platform
Full text linkA divacant Keggin polyanion has been decorated with a N-heterocyclic carbene (NHC) iridium(I) organometallic complex to provide a molecular model of an Ir-based supported catalyst. The characterization of the hybrid compound has been performed by multinuclear NMR spectroscopy, infrared spectroscopy, cyclic voltammetry, and mass spectroscopy, and the results are in agreement with a bisfunctionalization of the polyoxometalate scaffold. The resulting supported homogeneous complex has been successfully used to catalyze the transfer hydrogenation from iPrOH to benzophenone [with a turnover number (TON) of 680 and a turnover frequency (TOF) of up to 540 h–1].European Research CouncilEuropean Science Foundatio
Catalysis-Material Crosstalk at Tailored Nano-Carbon Interfaces
No full textThe use of carbon nanomaterials as supports for molecular and nanostructured catalysts is becoming a more and more popular strategy to improve heterogeneous catalysis. Their outstanding electronic and optical properties together with high surface area and thermal and mechanical stabilities make them ideal elements to provide catalysts with additional or improved characteristics. The role of the carbon nanostructures in the different types of catalysis is more intricate and often involves active and strong interactions between the support and the catalytic active species, creating a synergistic effect that in many cases leads to performance enhancement and an expanded range of possible applications. In particular, photocatalysis and electrocatalysis seem to benefit from the features of these types of carbon support, although applicability can be extended to more classic transformations of organic substrates
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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