Monolithic heterojunctions of CeO2/La2O3/TiO2 nanocomposites as visible-light capturing photoactive materials for fast and efficient clean-up of persistent pharmaceutical pollutants

We report the first of its kind synthesis of CeO 2 /La 2 O 3 nanocomposites that are with integrated mesoporous TiO 2 monoliths, with well-defined structural and surface properties, to act as visible-light responsive photocatalysts. The structural features of the photocatalyst materials are defined using HR-TEM, p-XRD, FE-SEM, SAED, EDAX, XPS, PLS, TGA, IR, UV–Vis–DRS and BET/BJH analyses. The stoichiometric infusion of CeO 2 /La 2 O 3 nanocomposites with the monolithic TiO 2 network reduces the bandgap energy from 3.26 to 2.52 eV, thus promoting excellent visible-light photocatalysis. To evaluate the photocatalytic efficiency of the proposed photoactive materials, two antimicrobial drugs namely, moxifloxacin and ciprofloxacin are selected as target pollutants. It is observed that the uniform and continuous porous monolithic network ensures easy transport of pollutant molecules to the photoactive sites, thereby felicitating their faster dissipation. The influence of various physico-chemical parameters has been studied by photolysis and photocatalysis procedures, and the extent of drug degradation is quantitatively analysed by using a robust HPLC-DAD method. The photocatalysis results reveal that the monolithic photocatalyst can serve efficiently for environmental remediation applications, with excellent reusability character. Graphic abstract