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Subject: search.filters.subject.Photocatalysts

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    Efficient and novel synthesis of Nb-doped SrTiO3 nanoparticles via microwave-assisted sol-gel auto-combustion
    (2025-02-01)
    Nunocha, Pornnipa
    ;
    Bongkarn, Theerachai
    ;
    Eiad-ua, Apiluck
    ;
    Channei, Duangdao
    ;
    Suriwong, Tawat
    This study employed microwave-assisted sol-gel auto-combustion to synthesize niobium-doped strontium titanate (SrTi<inf>1-x</inf>Nb<inf>x</inf>O<inf>3</inf>, STNO) nanoparticles, targeting enhanced photocatalytic performance applications. The STNO with varying levels of Nb doping (x = 0 to 0.05), was successfully synthesized utilizing the rapid and novel microwave-assisted sol-gel auto-combustion technique. The synthesized nanoparticles consistently exhibited a pure cubic perovskite structure across all doping levels, as confirmed by Rietveld refinement, which also showed an increase in lattice parameters and unit cell volume with higher Nb content. Morphological analysis revealed uniformly cubic-shaped particles with sizes ranging from 60 to 180 nm. The bandgap energy (E<inf>g</inf>) remained unaffected by the varying Nb doping levels. Regarding photocatalytic activity for the degradation of methylene blue (MB) dye and tetracycline (TC) antibiotic under UV-A LED irradiation, the photocatalytic performance of STNO was significantly enhanced with increasing Nb content. The optimal photocatalytic decolorization was achieved at x = 0.05, aligning well with findings derived from photoluminescence (PL), E<inf>g</inf>, Nyquist plot analyses and band edge potentials. Therefore, microwave-assisted sol-gel auto combustion is one of the efficient and novel methods to synthesize metal oxide materials.
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    Kinetics of dye removal using Fe3O4 nanoparticles and pulsed white-LED illumination
    (2019-01-01)
    Damrongsak, Pattareeya
    ;
    Klongratog, Bhanupol
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    Hoomsuk, Sirichai
    ;
    Locharoenrat, Kitsakorn
    Removal of dyes with the aid of photocatalytic nanomaterials illuminated with continuous-light sources has been given substantial attention in the recent years. In the present work we study the efficiency of dye degradation using some alternative photocatalytic nanoparticles under condition of pulsed illumination. Our specific purpose is to investigate the removal of rhodamine 6G dye basing on suspended Fe<inf>3</inf>O<inf>4</inf> solution. The experiments are carried out in the batch mode when the effect of the exposition time (ranging from 30 to 150 min) on the dye removal is examined under both continuous and pulsed white-LED illuminations. Different pulsed-light frequencies and duty cycles are tested. We estimate the concentration of rhodamine 6G in the mixed solution following from its absorption spectrum measured with a UV-Vis spectrometer and determine in this manner the percentage of dye removal. Our main conclusion is that Fe<inf>3</inf>O<inf>4</inf> nanoparticles enable removing efficiently the rhodamine 6G dye under pulsed white-LED illumination. In particular, more than 90% of the dye is removed when the duty cycle is equal to 25% and the frequency to 30 kHz. The equilibrium state of this process is achieved in about 60 min.
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    Removal of metals using a ZnO/Au composite under visible-light illumination
    (2018-01-01)
    Thonglim, P.
    ;
    Sirivichai, M.
    ;
    Thanjai, O.
    ;
    Locharoenrat, K.
    Gold nanoparticles embedded into a ZnO film are prepared with a simple spin-coating technique. Photocatalytic performance of the film is studied under irradiation with the visible light. We suggest to increase the amount of Au nanoparticles in the ZnO matrix (from 0 to 400 mg in our particular case) to improve photocatalytic efficiency of the film via a combination of plasmonic-resonance and Schottky-barrier effects. We choose Fe<sup>2+</sup> as a model representative of metals available in the wastewater. It is demonstrated that the ZnO/Au films with increased Au content reduce efficiently the amount of ferrum ions in the water solution. In particular, the film with the content ratio ZnO:Au = 1:2 serves as a good absorber for removing Fe<sup>2+</sup> in case if their initial concentration is equal to 0.2 mM.
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    Investigation of structural properties of CuPc/TiO2 nanocomposites
    (2010-02-05)
    Saributr, Chaloempol
    ;
    Makprasat, Wanichaya
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    Thanomngam, Pitiporn
    ;
    Pecharapa, Wisanu
    Structural properties of hybrid nanocomposites based on TiO<inf>2</inf> nanostructures and Copper phthalocyanine (CuPc) were investigated. The composites were prepared by mixing TiO<inf>2</inf> nanoparticle (TNP) and nanotube (TNT) with CuPc suspension. The precipitated composites were obtained by centrifuged and dried processes. Structural properties of the composites were evaluated by mean of Raman Spectroscopy and X-ray Absorption Fine Structure (XAFS). The results implied that CuPc has interatomic distance of C atoms in the second shell are decreased when CuPc is in the hybrid composites. © (2010) Trans Tech Publications.