Facile synthesis of cooperative mesoporous-assembled CexSr1-xFexTi1-xO3 perovskite catalysts for enhancement beta-lactam antibiotic photodegradation under visible light irradiation

Abstract

Results demonstrated in this work presented the synthesis of mesoporous Ce and Fe co-modified SrTiO3 (CexSr1-xFexTi1-xO3) perovskite materials using an innovative chelate complex approach, applying a molar excess of glycerol and citric acid monohydrate as the chelating agents. The influence of different Ce and Fe dopant concentrations (0 ≤ x ≤ 0.05) on the characteristics of the SrTiO3 catalysts were systematically investigated using multi-technique. The results showed that controlled Ce and Fe contents significantly altered the physical and chemical properties of the materials. The diffractogram confirmed that all prepared samples crystallized in a typical perovskite structure of SrTiO3 without deviation in the original cubic symmetry in perovskite structure when introduced Ce and Fe in the lattice. Likewise, the microscopy verified the uniformity and particle size reduction of the catalysts with increasing doping contents. In addition, all prepared samples illustrated mesoporosity and BET surface area slightly increased with increasing the doping elements and represented smaller than pure SrTiO3 sample. The Ce atom, replacing some Sr2+ in the lattice, was represented in Ce3+ and Ce4+ valence states mixture. At the same time, Fe atoms, presenting Fe3+ and Fe4+ oxidation states, cannot be incorporated by substituting Ti4+ ions in the SrTiO3 lattice structure, only incorporated with the interstitial site, as confirmed by XPS and XANES measurements. The Ce and Fe dopants improved the absorptivity towards a longer wavelength, resulting in decreasing bandgap energy. Their photocatalytic performance towards beta-lactam antibiotic degradation under visible light irradiation using an LED source was also evaluated. The Ce0.04Sr0.96Fe0.04Ti0.96O3 sample exhibited the best photocatalytic degradation of amoxicillin (67.4%) and demonstrated more activity than the pure SrTiO3 sample about 27 times. In the end, the synergistic effect of Ce and Fe dopants to help enhance the photocatalytic activity and the recycling ability were also detailed.