Probing the Site-Selective Doping in SrSnO3:Eu Oxides and Its Impact on the Crystal and Electronic Structures Using Synchrotron Radiation and DFT Simulations

The impact of Eu 3+ doping at the Sr 2+ and Sn 4+ sites in SrSnO 3 on its structural and electronic properties was studied and correlated with the photocatalytic efficiency. The compounds were synthesized using a modified Pechini method. Refinement of the synchrotron X-ray diffraction (S-XRD) data showed that the samples had an orthorhombic Pbnm symmetry. The incorporation of Eu into the lattice led to increased short- and long-range disorder, inducing additional distortion in the SnO 6 . XANES measurements revealed that mixed Eu valences (Eu 3+ and Eu 2+ ) were present in Eu-doped samples, and DFT calculations confirmed the presence of these ions at Sr 2+ /Sr 4+ sites in the SrSnO 3, resulting in changes in the electronic behavior. The catalytic performance toward Remazol yellow dye photodegradation and the catalysts’ surface properties were also evaluated. The catalytic efficiency followed the order of Sr(Sn 0.99 Eu 0.01 )SnO 3 > (Sr 0.99 Eu 0.01 )SnO 3 > SrSnO 3 . The order was clearly related to selected-site doping that changed the degree of the inter- and intraoctahedral distortion and the introduction of different Eu midgap states, which apparently favor charge separation upon photoexcitation during photocatalysis. The results shown here are of great importance to the functionalization of SrSnO 3 and other perovskite materials by lanthanoid ions, especially Eu 3+, for effective applications as photocatalysts.