Comparison of sol–gel and hydrothermal synthesis methods on the physical, and photocatalytic properties of Bi_1−xCe_xFe_1−xAl_xO₃ ferrites

The structural, magnetic properties and photocatalytic activity of pure-phase Bi_1−xCe_xFe_1−xAl_xO₃ (x = 0.0–0.06) synthesized via the sol–gel and hydrothermal methods were investigated. Rietveld refinement of X-ray diffraction patterns shows that the samples can be indexed to a rhombohedral unit cell (space group R3c). However, Raman spectra show an incomplete rhombohedral-tetragonal phase transition in the hydrothermally synthesized samples. Hysteresis loops indicate an improvement in magnetic parameters with the Ce/Al co-substitution. As the Ce/Al content increases, the band gap energy of the hydrothermal-synthesized samples increases from 1.97 to 2.66 eV, while it decreases from 1.52 to 1.26 eV in the sol–gel synthesized samples. Results of the degradation percentage of methyl orange show a decreasing trend with the Ce/Al content in the hydrothermally synthesized samples, while it increases in the samples sol–gel synthesized prepared. 95% degradation is obtained after 120 min at a pH of 2 and containing the 0.8 g/L of sol–gel synthesized Bi_0.94Ce_0.0.6Fe_0.94Al_0.06O₃.