Promoted photocatalytic mineralization of atrazine over visible-light active Ag2O/CeO2 nanocomposites with sustainable reusability

Abstract

Rare earth-based oxide heterojunction photocatalysts have recently demonstrated a significant role in environmental remediation for several pollutants under light irradiation. Particularly, the widespread use of hurtful weed killers such as atrazine (AtZ) in cultivation will induce several impacts on human health and the environment very soon. Thus, this work shows the application of a metal oxide nanocomposite photocatalyst composed of n-type nanostructured cerium oxide (CeO2) supported with p-type silver oxide (Ag2O) for the oxidative mineralization of AtZ in water. The Ag2O/CeO2 nanocomposites with the range of 1.0∼7.0 wt.% of Ag2O were synthesized by the surfactant-assisted sol-gel technique. The physicochemical characterizations of obtained materials indicated the formation of tiny Ag2O nanoparticles anchored to the cubic CeO2 nanocrystals by X-ray diffraction and transmission electron microscope. Also, the visible-light harvesting of Ag2O-loaded samples was better than pure CeO2 as a result of the narrowing of bandgap energy from 2.98 to 2.43 eV with the conservation of the mesostructured surface structure. The 7% Ag2O/CeO2 revealed the best-performed photocatalyst for the complete photooxidation of AtZ within 40 min at an amount of 2.0 g L–1 with a superb reaction rate of 79.23 × 10–3 min–1 and maintainable reusability of 96%. This novel p-n metal oxide heterojunction construction has endorsed the charge separation to the complete remediation of AtZ under visible light.