Synthesis of new oxygen deficient triple layered perovskite oxides LaSr3Fe3-xCrxO10-δ (x=0.0, 0.2, and 0.5): Structural, optical, magnetic and photocatalytic properties

In the present study, new oxygen deficient triple layered Ruddlesden-Popper (RP) phases LaSr3Fe3-xCrxO10-6 (x = 0.0, 0.2, and 0.5) have been prepared via sol-gel procedure. The prepared n = 3 RP phases were characterized with various characterization techniques in order to visualize the effect of Cr3+ doping on structural, optical, magnetic and photocatalytic properties. Rietveld structural refinements showed that all the phases crystallized in the I4/mmm space group with tetragonal symmetry. Dominant anti-ferromagnetic (AFM) interactions (Fe3+-O-Fe3+ and Fe4+-O-Fe4+) were noticed in each of these oxygen deficient triple layered phases with presence of weak ferromagnetic (FM) interactions. The decline in the values of Neel temperature (TN) with Cr doping has been interpreted on the basis of increase in FM Fe3+-O-Cr3+ interactions. The energy band gap values (Eg) of all the synthesised oxygen deficient phases vary from 1.63 to 1.73 eV, which makes them excellent photocatalysts for dye decontamination. Furthermore, the photocatalytic performance of the prepared phases was assessed by utilizing rhodamine B (RhB) dye as model dye pollutant. It was found that LaSr3Fe2.5Cr0.5O9.17 photocatalyst showed excellent results in the removal of RhB dye. As a result, we were further encouraged to extend the degradation to some other organic dyes such as methylene blue (MB), methyl orange (MO) and their mixture (RhB + MB + MO).