Acidic Peptizing Agent Effect on Anatase-Rutile Ratio and Photocatalytic Performance of TiO2 Nanoparticles

• Published in: Nanoscale research letters 2018-02, Vol.13 (1), p.48-48, Article 48
• Main Authors: Mahmoud, Hatem A., Narasimharao, Katabathini, Ali, Tarek T., Khalil, Kamal M. S.
• Format: Article
• Language: English
• Subjects: Chemistry and Materials Science; Degradation; Materials Science; Molecular Medicine; Nano Express; Nanochemistry; Nanoscale Science and Technology; Nanotechnology; Nanotechnology and Microengineering; NanoTiO2; Organic dyes; Peptizing acid; Photocatalysis; Raman
• ISSN: 1931-7573; 1556-276X
• DOI: 10.1186/s11671-018-2465-x

TiO 2 nanoparticles were synthesized from titanium isopropoxide by a simple peptization method using sulfuric, nitric, and acetic acids. The effect of peptizing acid on physicochemical and photocatalytic properties of TiO 2 powders was studied. The structural properties of synthesized TiO 2 powders were analyzed by using XRD, TEM, N 2 -physisorption, Raman, DR UV- vis , FTIR, and X-ray photoelectron spectroscopy techniques. The characterization results showed that acetic acid peptization facilitated the formation of pure anatase phase after thermal treatment at 500 °C; in contrast, nitric acid peptization led to a major rutile phase formation (67%). Interestingly, the sample peptized using sulfuric acid yielded 95% anatase and 5% rutile phases. The photocatalytic activity of synthesized TiO 2 nanoparticles was evaluated for degradation of selected organic dyes (crystal violet, methylene blue, and p -nitrophenol) in aqueous solution. The results confirmed that the TiO 2 sample peptized using nitric acid (with rutile and anatase phases in 3:1 ratio) offered the highest activity for degradation of organic dyes, although, TiO 2 samples peptized using sulfuric acid and acetic acid possessed smaller particle size, higher band gap energy, and high surface area. Interestingly, TiO 2 sample peptized with nitric acid possessed relatively high theoretical photocurrent density (0.545 mAcm −2 ) and pore diameter (150 Å), which are responsible for high electron-hole separation efficiency and diffusion and mass transportation of organic reactants during the photochemical degradation process. The superior activity of TiO 2 sample peptized with nitric acid is due to the effective transfer of photogenerated electrons between rutile and anatase phases.