Optical, photocatalytic properties of novel pyro- stannate A2Sn2O7 (A=Ce, Ca, Sr), and Pt deposited (SrCe)2Sn2O7 for the removal of organic pollutants under direct solar light irradiation

Abstract

Abstract The pyrochlore phase structured pristine Ce2Sn2O7, Ca and Sr cationic ions substituted Ce2Sn2O7 and Pt deposited (SrCe)2Sn2O7 photocatalysts have been prepared successfully by hydrothermal methods for environmental applications. The various physicochemical properties were characterized by several techniques such as X-ray diffraction (XRD), scanning electron microscope (SEM), high resolution transmission electron microscope (HRTEM), photoluminescence (PL) and UV–Vis absorbance spectroscopy, X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS). Substituting the alkaline earth elements such as Ca, Sr to lattice cerium in the Ce2Sn2O7 could lead to changes in the optical as well as the photocatalytic properties. The Pt deposited (SrCe)2Sn2O7 pyrochlore resulting the highly separated photogenerated carriers through the transfer of electrons, which is helpful to the photocatalytic performance. The Pt supported pyrochlore showed increased photocatalytic degradation of 4-Nitrophenol, RhB, MB and ciprofloxacin. The cyclic stability of the prepared materials was inspected; it was observed that the photo-catalyst is active for several cycles. The stimulated photocatalytic efficacy can be attributed to the extended response to the visible light, highly improved charge separation due to cationic substitution. Furthermore, super-oxide and hydroxyl are noticed to be the most important reactive species during the photo-degradation process. Our work provides a new path way to develop high performance stannate photocatalysts with the help of surface Plasmon resonance effect of Nobel metal nanoparticles, thus could widening the family of photocatalysts available for water treatment.