<p>An optimized Iron spinel ferrite (Fe₃O₄) synthesis for the highest catalytic activity by the ultrasonic-assisted reverse co-precipitation (US-RP) method was tested, substituting the divalent cation (Me²⁺) source from Fe²⁺ for Zn²⁺, Ni²⁺ or Co²⁺. The respective ZnFe₂O₄, NiFe₂O₄ or CoFe₂O₄ spinel ferrite nanoparticles were successfully synthesized in this work. The use of this US-RP method employing the ion source MeCl₂ (Me²⁺ = Zn²⁺, Ni²⁺ or Co²⁺) yields a magnetic biphasic monocrystalline composite MeFe₂O₄/α-Fe₂O₃ nanomaterial with potential photocatalytic properties. The amount of ferrite in the biphasic composite differed for each ion source, being 25.6%, 34.2%, and 38.2% for the CoFe₂O₄ &lt; NiFe₂O₄ &lt; ZnFe₂O₄, respectively. With an inverse trend in the magnetic properties, CoFe₂O₄ &gt; NiFe₂O₄ &gt; ZnFe₂O₄, with a magnetic saturation (<i>M</i>_s) of 42.5, 28.4, and 2.7 emu g⁻¹. These magnetic properties were attributed to the differences in the degree of inversion (<i>δ</i>) calculated from Raman spectroscopy and Rietveld refinements. As for the photocatalytic potential for nitrobenzene (NB) degradation, the half-life calculated under the tested conditions was in the range of 72 – 113 min, following a reaction mechanism that yields H2O, CO₂ and 4-nitrophenol (4-NPh) as an intermediate product (&lt; 5.65%). Showing an optimal efficiency at a pH = 2 when using the sample containing CoFe₂O₄.</p> Graphical Abstract <p></p>