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Author: search.filters.author.Thambiliyagodage, CSubject: search.filters.subject.graphene oxide

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    PublicationOpen Access
    Influence of ageing of graphene oxide on the properties and morphology of cement mortar
    (Nature Research, 2025-12-02) Suganthiny,G; Thambiliyagodage, C; Perera, S. V. T. J; Rajapakse, R. K. N. D
    Past studies show that Graphene Oxide (GO) enhances the structural properties of cement composites. However, GO reduces its chemical characteristics with ageing. This study determines the effects of the age of commercial and laboratory-produced GO on cementitious composites. The study considered GO of up to 35 weeks of age, and specimens were chemically characterised using various techniques. The ageing effects were evaluated using consistency, initial setting time, compressive strength, splitting tensile strength, and water absorption. The composite’s thermal resistance was also tested. GO was found to have a shelf life of 13 weeks from production to achieve favourable results. The morphology of the cement mortar was studied to determine the reason for the change in performance with GO age. This study confirms that the carbon-to-oxygen ratio (C/O) and the disorder of graphene oxide sheets (ID/IG ratio), along with the number of GO layers, govern the performance of GO-incorporated cement composites. Both ratios increase with GO age. Aged GOs in mortar increased the mean pore radius and reduced the surface area. Mortar samples with aged GOs have ettringite peaks, while early-age GO-containing samples lack ettringite peaks. Despite reduced mechanical performance with age, all mortar samples remained thermally stable at higher temperatures.
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    PublicationOpen Access
    Persulfate assisted photocatalytic and antibacterial activity of TiO2–CuO coupled with graphene oxide and reduced graphene oxide
    (https://www.nature.com, 2024-05-31) Thambiliyagodage, C; Liyanaarachchi, H; Jayanetti, M; Ekanayake, G; Mendis, A; Samarakoon, U; Vigneswaran, S
    Photocatalysts of TiO2–CuO coupled with 30% graphene oxide (GO) were hydrothermally fabricated, which varied the TiO2 to CuO weight ratios to 1:4, 1:2, 1:1, 2:1 and 4:1 and reduced to form TiO2–CuO/reduced graphene oxide (rGO) photocatalysts. They were characterized using XRD, TEM, SEM, XPS, Raman, and DRS technologies. TiO2–CuO composites and TiO2–CuO/GO degrade methylene blue when persulfate ions are present. Persulfate concentration ranged from 1, 2, 4 to 8 mmol/dm−3 in which the highest activity of 4.4 × 10–2 and 7.35 × 10–2 min−1 was obtained with 4 mmol/dm−3 for TiO2–CuO (1:4) and TiO2–CuO/GO (1:1), respectively. The presence of EDTA and isopropyl alcohol reduced the photodegradation. TiO2–CuO coupled with rGO coagulates methylene blue in the presence of persulfate ions and such coagulation is independent of light. The catalyst dosage and the concentration of the dye were varied for the best-performing samples. The antibacterial activity of the synthesized samples was evaluated against the growth of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella pneumonia. Ti:Cu (1:2)-GO and Ti:Cu (1:4)-GO had the highest antibacterial activity against K. pneumoniae (16.08 ± 0.14 mm), P. aeruginosa (22.33 ± 0.58 mm), E. coli (16.17 ± 0.29 mm) and S. aureus (16.08 ± 0.88).