Synthesis of TiOF2/CuO particles via coprecipitation method and their further thermal transformation to F-TiO2/CuO

• Published in: Chemical and process engineering (Berlin, Germany) Germany), 2024-02
• Main Authors: Sofronov, Dmitry, Rucki, Miroslaw, Lebedynskiy, Alexey, Mateychenko, Pavel, Minenko, Sergii, Shaposhnyk, Anna, Siemiatkowski, Zbigniew, Jozwik, Jerzy, Tofil, Arkadiusz
• Format: Article
• Language: eng ; pol
• ISSN: 2300-1925; 2300-1925
• DOI: 10.24425/cpe.2024.149463

The paper presents a novel, low-cost and simple route for synthesis of TiOF2/CuO and F-TiO2/CuO out of fluoride solutions. The obtained materials after calcination can be used in various photocatalytic applications, e.g. in water treatment. It was demonstrated that control of synthesis process parameters, such as pH, allowed for synthesis of particles with different phase composition and properties. Thus, pH≤4 environment had created conditions for formation of two structures of TiOF2, hexagonal and cubic ones, as well as CuTiF6(H2O)4. Increase of Cu content promoted increase of the cubic c-TiOF2 phase. When the solutions exhibited pH>5, the synthesized particles consisted of (NH4)2TiF6·2H2O, (NH4)3TiF7, and (NH4)2СuF4·4H2O. Calcination above 300 °С provided formation of TiOF2/CuO particles, while elevated temperatures of 600 °С ensured appearance of F-TiO2/CuO material. It was found that higher copper concentrations resulted with higher fluoride percentage after calcination at 600 °С. It was also demonstrated that F-TiO2/CuO particles synthesized at рН≤4 exhibited energy band gap Eg of 3.3–3.25 eV, which decreased down to 2.85 eV for higher copper(II) oxide concentrations of 10 wt.%. Notably, the particles F-TiO2/CuO synthesized at pH>5 exhibited band gap Eg of 3.4–3.5 eV, which decreased down to 2.9 eV for higher CuO concentrations.