Comparative study of the photocatalytic activity of anatase nanoparticles formed in metatitanic acid and titanium (IV) isopropoxide systems

DOI: 10.62564/M4-OL2026

Olena Lavrynenko, Maksim Zahornyi, Nadiya Tyschenko, Andrey Ragulya, Lesia Pavlenko

Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


Anatase particles are widely used to create photocatalytic materials due to their low cost, biosafety, and high efficiency. The synthesis method and the nature of the precursor compound are important factors affecting the nanomaterials' phase and chemical composition, structure, and properties. The purpose of the present work is to compare the photocatalytic activity of nanosized particles of titanium dioxide obtained in the titanium tetraisopropoxide (TTIP) and metatitanic acid (MTA) systems. According to XRD data, all the obtained samples correspond to anatase. The samples obtained in MTA systems are characterized by a lower degree of crystallinity and differ in the content of S impurity, which is ~0.035% in MTA (1) and ~0.83% in MTA (2), respectively. The CSR of MTA (1) particles is 8 nm, the crystal lattice parameters are a = 0.3765 nm, c = 0.9435 nm, the degree of tetragonality c/a = 2.506, V = 0.134 nm3. The CSR of MTA (2) particles is 11.5 nm, the parameters a = 0.3748 nm, c = 0.9407 nm, c/a = 2.51, V = 0.132 nm3. The CSR of TTIP particles is 9.1 nm, the parameters a = 0.3775 nm, c = 0.9479 nm, c/a = 2.51, V = 0.135 nm3. The values of the point of zero charge of the samples are as follows: MTA (1) = 6.37; MTA (2) = 5.02 and TTIP = 8.8. A comparison of the photocatalytic activity of the particles was carried out by UV-VL spectroscopy. According to the degree of discoloration of the day's solutions with the initial concentration of 20 mg/dm3 within 60 min, the efficiency series is determined. For Methyl Orange: TTIP 63.5% < MTA (1) 67.9% < MTA (2) 74.4 %. For Orange G: TTIP 28.0% < MTA (1) 95.5% < MTA (2) 99.75 %. For Methylene Blue: MTA (2) 59.0 < MTA (1) 70.2 < TTIP 91.0, and for Rhodamine B: MTA (1) 63.6 < TTIP 69.0%. The probable cause of this difference can be both the crystal structure of the samples, the presence of sulfur in their composition as active additive, and the surface charge of the anatase particles.

Keywords
Anatase, photocatalytic activity, discoloration, organic dyes

Acknowledgments
Dr O.M. Lavrynenko is supported by the PAUSE program, a national emergency program for scientists and artists in exile, run by the Collège de France.

References
[1] Lavrynenko O.M., Zahornyi M.M., Paineau E., Pavlenko O.Yu., Tyschenko N.I., Bykov O.I., Characteristic of TiO 2 \&;Ag 0 nanocomposites formed via transformation of metatitanic acid and titanium (IV) isopropoxide, Materials Today: Proceedings, 2022. https://doi.org/10.1016/j.matpr.2022.03.002