Facile Synthesis and Characterizations of Mixed Metal Oxide Nanoparticles for the Efficient Photocatalytic Degradation of Rhodamine B and Congo Red Dyes

Photocatalytic degradation has been suggested to be a cheap and efficient way to dispose of organic pollutants, such as dyes. Therefore, our research team strives to produce nanophotocatalysts in a simple and inexpensive way. In this work, the Pechini sol–gel technique was employed for the facile synthesis of Mn_0.5Zn_0.5Fe₂O₄/Fe₂O₃ and Fe_0.5Mn_0.5Co₂O₄/Fe₂O₃ as mixed metal oxide nanoparticles for the efficient photocatalytic degradation of Rhodamine B and Congo Red dyes. XRD, FT-IR, a N₂ adsorption/desorption analyzer, EDS, FE-SEM, and an UV–Vis diffuse reflectance spectrophotometer were used to characterize the produced samples. The XRD patterns revealed that the average crystallite size of the Fe_0.5Mn_0.5Co₂O₄/Fe₂O₃ and Mn_0.5Zn_0.5Fe₂O₄/Fe₂O₃ samples is 90.25 and 80.62 nm, respectively. The FE-SEM images revealed that the Fe_0.5Mn_0.5Co₂O₄/Fe₂O₃ sample consists of cubic and irregular shapes with an average diameter of 1.71 µm. Additionally, the Mn_0.5Zn_0.5Fe₂O₄/Fe₂O₃ sample consists of spherical shapes with an average diameter of 0.26 µm. The energy gaps of the Fe_0.5Mn_0.5Co₂O₄/Fe₂O₃ and Mn_0.5Zn_0.5Fe₂O₄/Fe₂O₃ samples are 3.50 and 4.3 eV and 3.52 and 4.20 eV, respectively. In the presence of hydrogen peroxide, the complete degradation of 100 mL of 20 mg/L of Rhodamine B and Congo Red dyes occurred at pH = 8 and 3, respectively, within 50 min, using 0.1 g of the synthesized samples.