KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Settings

Author: search.filters.author.Thongpool, VoranuchSubject: search.filters.subject.Photocatalysis

Search Results

Now showing 1 - 2 of 2
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Synergistic effects of biomass-derived carbon quantum dots and Cu Co-doping on TiO2 nanocomposite for enhanced visible-light photocatalysis
    (2026-12-01)
    Zhao, Huali
    ;
    Noonuruk, Russameeruk
    ;
    Bootchanont, Atipong
    ;
    Porjai, Porramain
    ;
    Thongpool, Voranuch
    The development of sustainable approaches for enhancing the visible-light activity of TiO<inf>2</inf>-based photocatalysts has attracted considerable research interest. In this work, carbon quantum dots (CQDs)-Cu co-modified TiO<inf>2</inf> nanocomposites were synthesized via a hydrothermal method using butterfly pea ( Clitoria ternatea ) flowers as a biomass-derived carbon source. The Cu content was fixed at 1.5 mol% relative to Ti, while the CQDs loading was controlled by varying the butterfly pea precursor concentration from 0.25 to 1.25 g L<sup>−1</sup>, yielding 1C–Cu–TiO<inf>2</inf>, 3C–Cu–TiO<inf>2</inf>, and 5C–Cu–TiO<inf>2</inf> samples. The prepared materials were characterized by electron microscopy, X-ray diffraction (XRD), UV–vis diffuse reflectance spectroscopy, photoluminescence (PL), and X-ray absorption spectroscopy (XAS). High-resolution transmission electron microscopy revealed CQDs with an average size of approximately 4.29 nm and an interplanar spacing of approximately 0.23 nm. All composites retained the anatase TiO<inf>2</inf> phase after Cu incorporation and CQDs modification. Enhanced visible-light absorption was observed and is attributed to the formation of Cu-related sub-band-gap states and the sensitization effect of CQDs. PL analysis showed an emission peak at ∼415 nm under 660 nm excitation, suggesting the presence of upconversion photoluminescence behavior in the CQDs. Conventional PL spectra further suggested reduced charge-carrier recombination in the modified composites. Photocatalytic activity was evaluated through Rhodamine B (RhB) degradation under visible-light irradiation. Among all samples, 1C–Cu–TiO<inf>2</inf> exhibited the highest performance, achieving degradation efficiency of 99.28% within 50 min. The apparent reaction rate constant reached 0.1038 min<sup>−1</sup>, which was 2.23, 1.96, and 2.90 times higher than those of pristine TiO<inf>2</inf>, Cu–TiO<inf>2</inf>, and 3C–Cu–TiO<inf>2</inf>, respectively. Radical scavenging experiments indicated that •OH and h<sup>+</sup> were the dominant reactive species, while •O<inf>2</inf><sup>−</sup> also participated in the degradation process. The enhanced photocatalytic performance is attributed to the synergistic effects of Cu and biomass-derived CQDs in improving visible-light harvesting and charge separation, providing an effective approach for developing visible-light-responsive TiO<inf>2</inf> photocatalysts.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Plant assisted synthesis of CuO/ZnO heterojunction nanocomposites using Mitragyna speciosa (Korth.) Havil leaf extract for photocatalytic activity under full spectrum LED light and antibacterial performance
    (2026-07-15)
    Phunpueok, Akapong
    ;
    Thongpool, Voranuch
    ;
    Jaiyen, Sarawut
    ;
    Bootchanont, Atipong
    ;
    Sukprasit, Nuchita
    CuO/ZnO heterojunction nanocomposites were synthesized through a green plant assisted method using Mitragyna speciosa leaf extract as a natural reducing and stabilizing agent. Structural and morphological analyses (XRD, FE-SEM, EDS, UV–vis, and BET) confirmed the formation of CuO/ZnO heterostructures with mesoporous characteristics. The 0.25CuO/0.75ZnO heterojunction nanocomposites exhibited the smallest ZnO crystallite size (∼8.06 nm) and the highest surface area (28.97 m<sup>2</sup>/g). Photocatalytic performance evaluated by methylene blue degradation under full-spectrum irradiation showed that the 0.25CuO/0.75ZnO heterojunction nanocomposites achieved 92.29% degradation within 90 min with a rate constant of 0.02491 min<sup>−1</sup>. In addition, the nanocomposites demonstrated strong antibacterial activity, achieving 99.9% reduction of E. coli and >99.9% inhibition of S. aureus . The enhanced performance is attributed to efficient charge separation at the CuO/ZnO heterojunction and the generation of reactive oxygen species.