Photo discoloration of eosin yellow dye under visible light using TiO2@TPPS nanocomposite synthesized via ultrasonic assisted method

Abstract This paper describes a new TiO2@TPPS (titanium dioxide @ tetraphenyl-porphyrin sulfonic acid) nanocomposite synthesized via ultrasonic assisted method using a bath-type ultrasonicator at 20 kHz (ultrasonic frequency) and 100 W (ultrasonic power). XRD (X-ray diffraction), FT-IR (Fourier-transform infrared spectroscopy), XPS (X-ray photoelectron spectroscopy), SEM (Scanning electron microscope), EDX (Energy-dispersive X-ray spectroscopy), and UV-DRS (Ultraviolet-visible spectroscopy) were used to systematically characterize the nanocomposite. Compared to TiO2, the TiO2@TPPS nanocomposite obviously exhibits higher photocatalytic activity towards EY (eosin yellow) dye degradation. The optimized weight ratio of 0.1 g of TiO2 nanosphere and 0.01 g of TPPS resulted in efficient discoloration of EY. The EY discoloration was 99 % within 50 min under visible light in the presence of the TiO2@TPPS nanocomposite. Additionally, the nanocomposite catalysts are highly stable and reusable for five consecutive experiments. This performance can be attributed to the synergistic effect of TiO2 and TPPS, which enhanced the charge separation and reduced the rate of recombination. The photodegradation mechanism was also investigated and discussed. It is expected that our work can offer a new way to develop binary nanocomposites with visible-region adsorption for photocatalytic discoloration of organic pollutants and energy applications.