Ox/Red-controllable combustion synthesis of foam-like PrFeO3 nanopowders for effective photo-Fenton degradation of methyl violet

Praseodymium orthoferrite nanopowders were synthesized by Red/Ox-controlled glycine-nitrate combustion followed by heat treatment. It was found that the temperature of PrFeO₃ formation from amorphous combustion products varied from 612 °C to 647 °C, depending on the initial reaction solution. The purity, crystallite size, morphology and specific surface area of ??the samples were affected by the glycine-nitrate ratio (G/N). At nonstoichiometric G/N (more or less than 0.6), amorphous or low crystalline phases were formed. Also, at these ratios, nanopowders had the smallest crystallite size before (17.4–36.2 nm) and after (45.3–49.2 nm) heat treatment. All powders were characterized by developed porous morphology with a specific surface area of ??2.9–11.9 m²/g and a band gap of 2.07–2.13 eV. The results of ⁵⁷Fe Mössbauer spectroscopy confirmed magnetically ordered state of PrFeO₃ nanocrystals with 1 mol % of amorphous component, associated with the combustion mode of a glycine-nitrate solution. The photocatalytic activity of PrFeO₃ was evaluated by the rate of decomposition of methyl violet (MV) in the presence of peroxide under the action of visible light.