Design, synthesis, and characterization of CeO2 and SnO2 nanoparticles for enhanced UVA-light-driven photocatalysis

In this study, XRD peak profile investigation was performed on CeO2-500 and SnO2-450 materials to assess microstructural parameters. Scherrer (SM, SEAM, and SSM), Monshi-Scherrer (MSM), Williamson-Hall, Size-Strain plot (SSPM), and Halder-Wagner (HWM) models were explored. Additionally, these materials were exploited in heterogeneous photocatalysis experiments. Structural characterization revealed the formation of cubic fluorite type CeO2 phase and pure tetragonal rutile structure of SnO2. All methods provide crystallite sizes within 10-12 nm for CeO2-500 and 20-30 nm for SnO2-450. SSPM gave the highest values of intrinsic strain and R2 (0.9975) along with satisfactory crystallite size, while the HWM model provided the highest R2 and exhibited a decrease in the intrinsic strain, which would suggest that lattice ε was isotropic in the environment. SEM analysis showed spherical NPs of CeO2-500 and consisted of a foamed body of SnO2-450. Both materials are legitimately transparent in the entire UV-Vis region with optical gap energy of 3.1 eV for CeO2-500 and 3.35 eV for SnO2-450. Ultimately, both materials exhibited excellent performance as a result of 76.44 and 61.63 % degradation achieved under UVA-light illumination for CeO2-500 and SnO2-450, respectively. Consequently, the outstanding degradation of CR could be can be synergistically explained by the photocatalysis oxidation procedure mechanisms through ROS (•OH, O2•− ) as the robust oxidizing agents implicated in oxidation and reduction processes with large intrinsic crystal defects (Ce4+-O and Sn4+-O defects sites) as primary driving forces ultimately facilitate charge separation of carriers, reduce their recombination rate and thus boost their photocatalytic effectiveness.