<p>This study used a sol-gel method to prepare BiFeO₃ (BFO) and strontium-doped bismuth ferrite Bi_1-xSr_xFeO₃ (x = 0, 0.01, 0.03, 0.05 and 0.09) (Sr-doped BFO) photocatalysts. The microstructural analysis of the Sr-doped BFO photocatalysts revealed a rhombohedral perovskite structure in the samples. The optical study shows that doping with Sr ions reduced the energy band gap of the photocatalyst from 2.12 eV to 1.97 eV. Moreover, the calculated saturation magnetization (Ms) value was increased after doping with Sr ions, and for Sr (x = 0.05), the doped BFO sample exhibits the highest magnetization value of 0.481 emu/g. It was revealed that the Sr (x = 0.05) doped BFO photocatalyst exhibits 91.2% degradation of methylene blue (MB) dye under visible light radiation. In this study, the formation of trap levels due to the Sr ions, as well as the formation of superoxide anions (<InlineEquation ID="IEq1"> <EquationSource Format="TEX">\({O}_{2}^{-}\)</EquationSource> <EquationSource Format="MATHML"><math> <msubsup> <mrow> <mi>O</mi> </mrow> <mrow> <mn>2</mn> </mrow> <mrow> <mo>−</mo> </mrow> </msubsup> </math></EquationSource> </InlineEquation>) and OH° radicals played a significant role in the degradation of MB.</p> Graphical Abstract <p></p>