The Effect of Alkaline Ratios of NaOH to NH₃ on the Formation of Nanostructured Titania

Abstract:

The effect of alkaline solvent of NaOH and NH₃ in the synthesis of nanostructured titania (TiO₂) has been studied. Powder of anatase titania as the precursor was mixed with various volume ratios of 10 M of NaOH and 15 M of NH₃. The mixture was heated in Teflon-lined autoclave at 150 °C for 24 h. The as-synthesized TiO₂ powders were then washed with 0.1 M HCl and calcined at 300 °C. The calcined samples were characterized using TEM (transmission electron microscope), and XRD (X-Ray diffraction). Raman spectroscopy was further used to determine the contributing crystalline phases for the synthesized TiO₂. It is shown that varying the solvent ratios of NOH to NH₃ resulted in nanotubes, nanosheets, and nanoparticle morphology of TiO₂. The TEM images showed the formation of nanotube structure in alkaline ratio NaOH:NH₃ of 1:0 and 3:1, with diameter of about 10 nm. At volume ratio of 1:1, the nanosheets and nanotubes both were formed and at volume ratio of NaOH:NH₃ of 1:3, nanosheets contributed as its main morphology. While, at fully NH₃ solvent, the nanospheres with anatase domain were produced. Raman spectra confirmed that the major contributor for hydrothermal synthesis employing less NaOH for volume ratio of NaOH:NH₃ of 3:1 was predominantly anatase with slight presence of titanate. For volume ratio at higher NH₃ the presence of titanate is not prominent, but the morphology has already changed into more nanosheet and then nanospheres. The crystallinity of TiO₂ anatase crystalline phase was enhanced as more NH₃ utilized.

• Periodical: Materials Science Forum (Volume 886)
• Pages: 42-47
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.886.42
• Online since: March 2017
• Authors: Indriana Kartini*, Inna Yusnila Khairani, Chotimah Chotimah, Salim Mustofa, Sri Juari Santosa, Lian Zhou Wang
• Keywords: Alkaline Hydrothermal, Nanoparticle, Nanosheet, Nanostructured TiO₂, Nanotubes

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