Brij 58–activated carbon assisted synthesis of Ag/Ag2O/TiO2-AC photocatalysts for efficient organic pollutants degradation

TiO2-activated carbon composites with mesoporous structure were prepared by sol-gel method using different titanium precursors (titanium tetraisopropoxide, tetraethyl orthotitanate) and surfactants (Brij 58 and activated carbon). Two different activated carbons (AC and ACP), obtained from ground coffee, were activated in different conditions with orto-phosphoric acid. Finaly the obtained supports were dopped with Ag (1%). The crystalline structure, morphology, mesoporous structure, surface composition and optical properties of Ag/Ag2O/C/P/TiO2 photocatalysts were characterized by X-ray diffraction (XRD), BET surface area measurements, scanning and transmission electron microscopy (SEM, TEM), X-ray photoelectron spectroscopy (XPS), Raman, diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) techniques. A significant effect of activated carbon and titanium precursor on TiO2 crystalline phase was evidenced. Thus, XRD and TEM evidenced amorphization of TiO2 structure for samples with high phosphorus percent in activated carbon. As well, a small amount of rutile, together anatase, stood out for samples obtained from tetraethyl orthotitanate. XPS spectra revealed the presence of Ag1+, Ag0, C-C, C-O, C-P, and P-O species on the surface with significant effect on adsorption and photocatalytic degradation of Brilliant Blue FCF dye and antibiotic Ciprofloxacin. The best activity and no toxicity of the obtained water after Ciprofloxacin photodegradation was evidenced for the sample with higher P content. The obtained results highlighted that activated carbon play an outstanding role in the mechanism of dye and antibiotic photodegradation influencing both the adsorption of organic molecules and photocatalytic performances of p-n Ag2O/TiO2 heteroconjunction from composite materials.