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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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    Effect of Nb doping on the structural, optical, and photocatalytic properties of SrTiO3 nanopowder synthesized by sol-gel auto combustion technique
    (2022-01-01)
    Nunocha, Pornnipa
    ;
    Kaewpanha, Malinee
    ;
    Bongkarn, Theerachai
    ;
    Eiad-Ua, Apiluck
    ;
    Suriwong, Tawat
    Metal oxide photocatalyst is a promising wastewater treatment process due to its simplicity, high efficiency, and low cost, as well as being environmentally friendly and non-energy consuming. The perovskite structure material, SrTi<inf>1−</inf><inf>x</inf> Nb <inf>x</inf> O<inf>3</inf> (STNO) with x = 0, 0.01, 0.03, and 0.05, was successfully synthesized by the sol-gel auto-combustion method. Samples with a pure phase and cubic perovskite structure were obtained. The Rietveld refinement results showed that the lattice parameter and unit cell density increased as the Nb-doping level increased. The particle size of the STNO decreases with increasing Nb doping content. Photoluminescence was excited at 327 nm, producing violet, green, and blue emissions, while the Nb content asserts an insignificant effect on the bandgap (E<inf>g</inf>). The Nyquist plot and Mott-Schottky analysis were used to determine the photoelectrode performance of the STNO samples. The photocatalytic activity of STNO on the decolorization of methylene blue (MB) under UV irradiation increased with increasing Nb content and optimization at x = 0.05, corresponding to the results obtained from photoluminescence, E<inf>g</inf>, Nyquist plot, and Mott-Schottky analyses.
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