Silver-photodeposited TiO2-clay nanocomposite: sol–gel synthesis, characterization and CCD-optimized photocatalytic activity

• Published in: Journal of the Iranian Chemical Society 2023, Vol.20 (1), p.217-230
• Main Authors: El Gaidoumi, Abdelali, Tanji, Karim, Loqman, Amal, El Mrabet, Imane, Fahoul, Youssef, Arrahli, Abdellah, Dra, Abdelaziz, Zouheir, Morad, El Bali, Brahim, Kherbeche, Abdelhak
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Biochemistry; Catalytic activity; Chemical synthesis; Chemistry; Chemistry and Materials Science; Clay; Clay minerals; Hydrogen peroxide; Inorganic Chemistry; Irradiation; Mineralization; Nanocomposites; Optimization; Organic Chemistry; Original Paper; Oxidation; Phenols; Photocatalysis; Photocatalysts; Photodegradation; Physical Chemistry; Polynomials; Pyrophyllite; Response surface methodology; Silver; Sol-gel processes; Statistical models; Titanium dioxide; Toxicity; Ultraviolet radiation
• ISSN: 1735-207X; 1735-2428
• DOI: 10.1007/s13738-022-02668-8

Nanocomposites of TiO 2 -clay were synthesized by the sol–gel route. The materials were characterized by XPS, XRD, UV–Vis DRS and BET surface area. Photocatalytic activity under UV irradiation ( λ max  ≈ 365 nm) was investigated by means of the phenol oxidation reaction. It was observed that the UV-photocatalytic property of TiO 2 -clay nanocomposite (SG) ( E gap  = 3.17 eV, S BET  = 16.58 m 2  g −1 ) for the phenol photodegradation was higher than that of commercial AEROXIDE® TiO 2 P25. The activity of SG was greatly improved after silver photodeposition; in fact, the silver-photodeposited into SG highly enhanced the phenol degradation and mineralization efficiencies. The optimization of different experimental parameters, such as the photocatalyst amount, pH, temperature or hydrogen peroxide concentration on the phenol photodegradation under UV irradiation was studied with photodeposited catalyst 1.5%Ag/SG ( E gap  = 3.12 eV, S BET  = 12.16 m 2  g −1 ) based on the response surface methodology selecting composite central design as statistical model. Based on the ANOVA analysis, simulations explained a good fit to the experimental data involving a second-degree polynomial model with a model F -value of 73.31 and coefficient of determination ( R 2 ) value of 0.9959. Optimal experimental conditions were found to be a photocatalyst amount of 2 g L −1 , solution pH of 5, temperature of 40 °C and hydrogen peroxide concentration of 8 mmol L −1 . Under these optimized conditions, total degradation, 91% mineralization and non-toxicity were found, at 50 mg L −1 phenol during 120 min of reaction. Overall, pyrophyllite clay is very attractive as a natural and low-cost mineral for elaborating efficient photocatalysts.