Photocatalytic mitigation of rhodamine B dye over novel FeS2/CeO2 nanocomposites through step S-scheme mechanism

Photothermal nanoparticles are recent materials which provide additional capacity supply during the photocatalytic reactions. Iron disulfide (FeS 2 ) nanoparticles with unique chemical and optical properties effectively absorb the full broad spectrum and convert the solar energy into chemical energy owing to its small band gap energy of 1.5 eV. However, the fast electron–hole pair recombination reduces the efficiency of FeS 2 and depresses the redox reaction. In this novel research, FeS 2 /CeO 2 heterojunctions are prepared for successful decomposition of rhodamine B dye as toxic pollutant belonging to xanthene dye group. CeO 2 nanoparticles are fabricated through sol–gel procedure via triton- × 100 as pore directing agent. Nanoparticle’s FeS 2 is developed by the precipitating process under a N 2 -atmospheric condition. Various amounts of FeS 2 particles were deposited in ultrasonic bath onto the surface of CeO 2 . The nanostructures, crystalline and optical properties of the solid specimens are evaluated by scanning and transmission electron microscopy (SEM and TEM) with Energy-dispersive X-ray spectroscopy (EDS), x-ray diffraction (XRD), photoluminescence (PL) and diffuse reflectance spectroscopy (DRS) techniques. The photocatalytic efficiency of CeO 2 , FeS 2 and various compositions of FeS 2 /CeO 2 heterojunction was deliberated via following the decomposition of rhodamine B dye under UV radiation at 365 nm. FeS 2 efficiently transfers the absorbability of the nanocomposite to deep visible region by decreasing the band gap energy of CeO 2 from 2.3 to 1.5 eV revealing that FeS 2 determines the optical properties of the nanocomposites. The charge transportation proceeds through type (I) heterojunction with accumulation of the massive charge carriers in the valence and conduction bands of FeS 2 nanoparticles. The novel nanocomposite with strong absorbability of nearly full absorption spectrum could be an effective photocatalyst for decomposition of toxic organic dye from various sources of water.