Browsing by Author "Hamdy, Louise B."

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    Investigation into the Re-Arrangement of Copper Foams Pre- and Post-CO2 Electrocatalysis
    (MDPI, 2021) Rudd, Jennifer A.; Hernandez-Aldave, Sandra; Kazimierska, Ewa; Hamdy, Louise B.; Bain, Odin J.E.; Barron, Andrew R.; Andreoli, Enrico
    The utilization of carbon dioxide is a major incentive for the growing field of carbon capture. Carbon dioxide could be an abundant building block to generate higher-value chemical products. Herein, we fabricated a porous copper electrode capable of catalyzing the reduction of carbon dioxide into higher-value products, such as ethylene, ethanol and propanol. We investigated the formation of the foams under different conditions, not only analyzing their morphological and crystal structure, but also documenting their performance as a catalyst. In particular, we studied the response of the foams to CO2 electrolysis, including the effect of urea as a potential additive to enhance CO2 catalysis. Before electrolysis, the pristine and urea-modified foam copper electrodes consisted of a mixture of cuboctahedra and dendrites. After 35 min of electrolysis, the cuboctahedra and dendrites underwent structural rearrangement affecting catalysis performance. We found that alterations in the morphology, crystallinity and surface composition of the catalyst were conducive to the deactivation of the copper foams.
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    Overcoming mass transfer limitations in cross-linked polyethyleneimine-based adsorbents to enable selective CO2 capture at ambient temperature
    (Royal Society of Chemistry, 2022) Hamdy, Louise B.; Gougsa, Abel; Chow, Wing Ying; Russell, James E.; García-Díez, Enrique; Kulakova, Viktoriia; Garcia, Susana; Barron, Andrew R.; Taddei, Marco; Andreoli, Enrico
    New self-supported polyamine CO2 adsorbents are prepared by cross-linking branched polyethyleneimine (PEI) with 2,4,6-tris-(4-bromomethyl-3-fluoro-phenyl)-1,3,5-triazine (4BMFPT). Controlling the degree of cross-linking to ensure abundant free amine functionalities while maintaining a structure conducive to efficient mass transfer is key to accessing high CO2 adsorption and fast kinetics at ambient temperature. The polyamine-based adsorbent, PEI-4BMFPT, 10 : 1 (R), is composed of spherical particles up to 3 μm in diameter and demonstrates fast CO2 uptake of 2.31 mmol g−1 under 1 atm, 90% CO2/Ar at 30 °C. Its CO2/N2 selectivity, predicted by the ideal adsorbed solution theory is 575, equalling that of highly selective metal–organic frameworks. Based on humidified thermogravimetric analysis, it was observed that the presence of water promotes CO2 uptake capacity of 10 : 1 (R) to 3.27 mmol g−1 and results in strong chemisorption; likely by formation of ammonium carbonate and bicarbonate species. It is observed that CO2 uptake enhancement is highly subject to relative humidity and CO2 partial pressure conditions. When adsorption conditions combined low temperatures with low partial pressure CO2, 10 : 1 (R) showed reduced uptake. Tested under breakthrough conditions representative of post-combustion conditions, at 75% RH and 40 °C, CO2 uptake was reduced by 83% of the dry adsorption capacity. This body of work further advances the development of support-free CO2 adsorbents for ambient temperature applications and highlights the drastic effect that relative humidity and CO2 partial pressure have on uptake behaviour.
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    The application of amine-based materials for carbon capture and utilisation: an overarching view
    (Royal Society of Chemistry, 2021) Hamdy, Louise B.; Goel, Chitrakshi; Rudd, Jennifer A.; Barron, Andrew R.; Andreoli, Enrico
    In the ongoing research campaign to reduce the global atmospheric CO2 concentration, technologies are being developed to enable the capture of CO2 from dilute sources and conversion into higher-value products. Amine and polyamine-based materials feature widely in the literature as solid CO2 sorbents and as catalyst modifiers for CO2 electrochemical reduction; however, advancing lab-scale research into a pilot or industrial-scale application is fraught with challenges, starting with the definition and identification of an effective adsorbent. This multidisciplinary review serves as an essential introduction to the role of amines in carbon capture and utilisation for scientists entering and advancing the field. The chemical and engineering principles of amine-based CO2 capture are considered to define the parameters required of an adsorbent, describe adsorption testing methods, and introduce the reader to a range of amine-based adsorbents and how they can be specialised to overcome specific issues. Finally, the application of electrocatalysts modified with nitrogen-containing compounds and polymers is reviewed in the context of CO2 utilisation.