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The CuFe2O4 photocatalysts were synthesized by the solution combustion synthesis method, followed by heat treatment at a temperature range of 400 to 1100 °C. Later, they were characterized for application in the photodegradation of synthetic dyes under visible radiation. The X-ray diffraction results showed the presence of cubic and tetragonal phases of CuFe2O4 and secondary phases of Fe2O3 and CuO, at low temperatures. The infrared spectrum profile confirms the formation of the phases pointed out in the XRD. For most specimens, the scanning electron microscopy examination revealed a morphology similar to porous flakes and a quasi-spherical shape. On the other hand, samples heat-treated at 1100 °C displayed a plate-like morphology. The specimens’ band gap ranged from 1.49 to 1.58 eV, indicating that the material is a semiconductor. Regarding the photocatalytic efficiency, the 400 °C heat-treated samples showed better activity when the visible irradiation was used over the green malachite and rhodamine B dyes. The solution degradation rates on the first and former dyes were 56.60% and 84.30%, respectively.

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MnTiO 3 is a semiconductor that has relevant dielectric and optical properties. For the synthesis of manganese titanate (MnTiO 3) powders, the combustion method via microwave and subsequent calcination at 500, 700, and 900 °C were used. The structural, morphological, and optical properties of the samples were investigated. X-ray diffraction analyzes were performed, where it was possible to index all peaks in the pyrophanite phase with a rhombohedral structure for the 900 °C sample. FTIR spectra corroborate the diffraction results, showing the presence of the vibrational modes characteristic of the MnTiO 3 bonds. SEM images revealed the formation of distorted nanobands with an average diameter of 320 nm. The optical spectrum obtained from the UV-vis absorption spectroscopy suggested a bandgap for MnTiO 3 of around 3.18 eV. The present work showed that combustion synthesis via microwave is efficient for the production of pure manganese titanate after calcination at 900 °C for 2 h.