Competitive coordination strategy for preparing TiO2/C nanocomposite with adsorption-photocatalytic synergistic effect

Abstract

The synergistic adsorption-photodegradation effect has been used to form TiO2-based photocatalyst but is limited by the multi-step preparation strategy. The present study employed the “one-pot” method to form the precursor via a competitive coordination strategy. Ca2+/Ti4+-alginate coordination complex was prepared and further carbonized to C-TiO2/CaCO3 nanocomposites for methylene blue (MB) removal. The resultant materials were characterized by FT-IR, XRD, XPS, UV–Vis DRS, TG-DTA, BET, and SEM-EDS techniques, and their synergistic adsorption-photodegradation performance on MB was also studied under simulated sunlight. Results indicated that the anatase-rutile phase of TiO2 in the nanocomposite transformed to the anatase phase by adding CaCl2. The C-TiO2/CaCO3 nanocomposite presented higher specific surface area, pore volume, and mean pore size and consequently showed enhanced adsorption capacity. Low bandgap energy determined an excellent photocatalytic activity, and the degradation ratio of MB reached 96.46% within 10 min. The cycling photodegradation of MB indicated high cycling stability. The C-TiO2/CaCO3 composites made by this simple method have synergistic adsorption-photodegradation performance and can be reused after regeneration, opening up a sustainable opportunity for wastewater treatment.