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X-ray absorption spectroscopy data from the thesis 'Operando X-ray studies of gas evolving and consuming catalysts'
No full textXAS data published in Sherwin, C. M. (2024). Operando X-ray studies of gas evolving and consuming catalysts. [Doctoral Thesis, University of Southampton] is stored at the Diamond Light Source, where it was created.
All data is available under proposals: NT35412-1, NT35671-1, SP10915-1, SP30590-1, SP32881, SP33009-1, SP35072.
The data available under a Creative Commons Attribution licence after an initial embargo of 3 years, lasting until September 2027.
To access the data, users must create an account with Diamond on their data gateway: https://icat.diamond.ac.uk/</span
Operando X-ray studies of gas evolving and consuming catalysts
No full textThe inherent intermittency of renewable energy production is one of the major challenges facing a future powered by renewable sources. Electrolysers are a potential solution to buffer this intermittency through production of green hydrogen. The electrochemical conversion of carbon dioxide (CO2) to useful chemicals and fuels is another a promising route toward the achievement of carbon neutral and carbon negative energy technologies. Fully understanding the catalytic and degradation mechanisms at current densities relevant for industrial application of these processes is therefore paramount for further catalyst improvement.In this work a novel in situ specto-electrochemical X-ray absorption cell is presented as a new setup for collecting XAS data of gas evolving and consuming electrocatalysts at high overpotentials. Utilising a thin, porous PTFE membrane coated in gold to act as a current collector, coupled with efficient gas and electrolyte circulation loops, interference from bubble formation is minimised. The ability of the cell in characterising gas evolution / consumption reactions is demonstrated in the study of three reactions, the oxygen reduction reaction, oxygen evolution reaction and carbon dioxide reduction reaction. A detailed XAS investigation of highly dispersed platinum during the oxygen reduction reaction is presented, along with comparative data in nitrogen. These measurements show the preservation of oxygen on the surface of the platinum nanoparticles below the platinum oxide reduction peak (0.48 VRHE). A range of highly active iridium oxides were investigated for the oxygen evolution reaction. Hydrated and rutile type iridium oxide XAS spectra were measured potentiodynamically, and it is found that a plateau region occurs in the oxidation states of hydrated iridium oxide at characteristic potentials for each material. This plateau region is attributed to the formation of a low conductivity Ir3+ species, the formation of which is also found in iridium oxides prepared by Adams Fusion method and demonstrates the structural variations in the materials that lead to their high activity. Finally, oxide derived copper is investigated for the CO2 reduction reaction during reduction / re-oxidation cycles and various oxides of copper are formed which are reduced immediately upon CO2 reduction
Cathodes for Electrochemical Carbon Dioxide Reduction to Multi-Carbon Products: part II rapid improvement in cathode performance
No full textThis is Part II of a focused review of recent highlights in the literature in cathode development for low temperature electrochemical carbon dioxide and carbon monoxide reduction to multicarbon (C2+) products. Part I (1) introduced the role of CO2 reduction in decarbonising the chemical industry and described the catalysts and modelling approaches. Part II describes in situ characterisation to improve the understanding and development of catalysts, the catalyst layer and the gas diffusion layer.</p
Cathodes for electrochemical carbon dioxide reduction to multi-carbon products: part I : a focused review of recent highlights
No full textThis is a focused review of recent highlights in the literature in cathode development for low temperature electrochemical carbon dioxide and carbon monoxide reduction to multi-carbon (C2+) products. The major goals for the field are to increase Faradaic efficiency (FE) for specific C2+ products, lower cell voltage for industrially relevant current densities and increase cell lifetime. A key to achieving these goals is the rational design of cathodes through increased understanding of structure-selectivity and structure-activity relationships for catalysts and the influence of catalyst binders and gas diffusion layers (GDLs) on the catalyst microenvironment and subsequent performance
Rhodium-decorated palladium nanocubes supported on Ni(OH)<sub>2</sub> nanosheets/C for enhanced ethanol oxidation
No full textThis study investigates the improvement of Palladium (Pd)-based nanocatalysts for ethanol oxidation in alkaline solutions, a process often hindered by the poisoning of the catalyst’s surface. We synthesise Pd nanocubes and Rhodium (Rh)-decorated Pd nanocubes, both supported by a composite of nickel hydroxide nanosheets and carbon (Ni(OH)2/C). The developed Pd nanocatalysts possess a nanocubic morphology with smaller sizes compared to Pd/C, alongside additional nanostructures like nanorods X-ray absorption near-edge structure and extended X-ray absorption fine structure analyses suggest that Rh decoration on Pd nanocubes prevents Pd oxidation, with Rh itself being oxidised. The electrocatalytic performance of the Rh/Pd/Ni(OH)2/C hybrid catalyst displays a notable enhancement, attributed to the combined effects of the exposed Pd (1 0 0) crystal surfaces, the addition of oxygenated species through the Ni(OH)2 component, and the deliberate addition of Rh. Comparative assessments reveal that this composite surpasses Pd/C and Pd/C nanocubes, achieving specific activities that are approximately 11.6 and 3.5 times greater, respectively. Electrochemical Impedance Spectroscopy data and chronoamperometric studies confirm superior ethanol oxidation efficiency and improved catalytic stability. These findings highlight the utility of Rh/Pd/Ni(OH)2/C nanocubes in direct ethanol fuel cells, providing promising pathways for enhancing fuel cell technologies
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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