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Author: search.filters.author.Boonruang, ChatdanaiSubject: search.filters.subject.Photocatalyst

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    Synergy of functionalized activated carbon and ZnO nanoparticles for enhancing photocatalytic degradation of methylene blue and carbaryl
    (2024-10-01)
    Rungsawang, Tipawan
    ;
    Krobthong, Sucheewan
    ;
    Paengpan, Krisanachai
    ;
    Kaewtrakulchai, Napat
    ;
    Manatura, Kanit
    This study proposes preparing ZnO and ZnO/activated carbon (AC) for photocatalytic applications. ZnO and AC were synthesized using precipitation and carbonization processes, respectively. Particle sizes of ZnO and ZnO/AC were estimated at 121–135 nm. The crystalline structure analysis confirmed the presence of hexagonal wurtzite structures in ZnO. Microcrystalline graphite and amorphous carbon structures were observed in AC. The combination of these characteristics was observed in ZnO/AC. ZnO/AC exhibited an increase in surface area from 25.36 to 29.86 m<sup>2</sup>/g and a decrease in pore diameter from 5.66 to 4.31 nm. The chemical states of ZnO and AC remained unchanged. Therefore, the nanocompound structure of ZnO/AC can be inferred. The ZnO/AC nanocompounds were then employed to degrade methylene blue (MB) dye and carbaryl (CBR) insecticide, demonstrating excellent photocatalytic performance compared to pure ZnO. The apparent degradation rate constant reached an average value of 3.49 × 10<sup>−3</sup> and 16.25 × 10<sup>−3</sup> min<sup>−1</sup> for MB and CBR, respectively. AC functions as carrier collectors in the ZnO/AC nanocompound structures due to the suitable energy band level for facilitating electron and hole transfers. This results in recombination suppression and prolonged lifetime, thus enhancing photocatalytic activity. The finding suggests the potential use of ZnO/AC nanocompounds to degrade agricultural chemicals in contaminated natural water under sunlight.
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    A novel photocatalyst of Y2O3-BaO-ZnO ternary system for enhanced photocatalytic degradation of carbofuran insecticide
    (2024-08-01)
    Sujinnapram, Supphadate
    ;
    Krobthong, Sucheewan
    ;
    Moungsrijun, Sasimonton
    ;
    Boonruang, Chatdanai
    ;
    Kaewtrakulchai, Napat
    A novel Y<inf>2</inf>O<inf>3</inf>-BaO-ZnO ternary system was synthesized via precipitation of a mixture of Y(NO<inf>3</inf>)<inf>3</inf>.6 H<inf>2</inf>O:Ba(NO<inf>3</inf>)<inf>2</inf>:Zn(NO<inf>3</inf>)<inf>2</inf>.6 H<inf>2</inf>O using some Fibonacci sequences. The Y<inf>2</inf>O<inf>3</inf>-BaO-ZnO was applied to the photocatalyst to investigate the degradation of carbofuran insecticide. The Y<inf>2</inf>O<inf>3</inf>-BaO-ZnO prepared at the sequence ratio of 5:8:13 (YBZ5) exhibited the highest photocatalytic performance. Morphological characterization showed that the particle size of the YBZ5 sample was significantly smaller than that of ZnO by over half, possibly providing high surface areas. The crystalline structure, functional group, and surface chemical composition investigations confirmed the presence of Y<inf>2</inf>O<inf>3</inf>, BaO, and ZnO. The fluorescence study exhibited no difference. Based on band gap energy and energy band alignment analysis, the Y<inf>2</inf>O<inf>3</inf>-BaO-ZnO ternary system demonstrated a well-aligned valence band. The energy band alignment analysis revealed a good alignment of the valence band for continuous hole transport in the Y<inf>2</inf>O<inf>3</inf>-BaO-ZnO ternary system. The alignment induces charge separation which reduces recombination and provides efficient active carriers at the surfaces of the photocatalyst, allowing reactions with toxic molecules. Therefore, the synergistic function of high surface areas and appropriate energy band alignments of the novel Y<inf>2</inf>O<inf>3</inf>-BaO-ZnO ternary system is considered the crucial factor in the enhancement of photocatalytic performance.