Effect of B-site Co substitution on the structure and magnetic properties of nanocrystalline neodymium orthoferrite synthesized by auto-combustion

Synthesis and Mechanism of Co2+/Sr2+ Codoped Magnetic Lanthanum Cuprate with Excellent Corrosion Resistance

The special structure of perovskite-like compounds allows the existence of some open spaces in the crystals that play an important role in their crystal function enhancement and can accommodate active oxygen, which helps to solve some problems in the field of corrosion prevention. The magnetic lanthanum cuprate was obtained through the doping of Co2+ and Sr2+, and compared with La2CuO4 and epoxy resin, its corrosion resistance was improved by 215.2 and 566.7%, respectively. The micromagnetic field in the crystal interfered with the state of motion of the electrons and prolonged their transport path. High concentration doping and substitution of unequal states led to the formation of oxygen vacancy defects, which could trap active oxygen molecules and inhibit cathodic corrosion reactions. The unique alternating interlayer structure of perovskite-like compounds was conducive to the release of Cu2+, thus forming a more stable passivator on the surface of the coating. La1.96Sr0.04Cu0.98Co0.02O4 had both magnetic properties and structural advantages, which enhanced the shielding property of epoxy resin and expanded the application of perovskite-like compounds in the field of corrosion prevention.

Optical and Photocatalytic Properties of Cobalt-Doped LuFeO3 Powders Prepared by Oxalic Acid Assistance

B-site cobalt (Co)-doped rare-earth orthoferrites ReFeO3 have shown considerable enhancement in physical properties compared to their parent counterparts, and Co-doped LuFeO3 has rarely been reported. In this work, LuFe1-xCoxO3 (x = 0, 0.05, 0.1, 0.15) powders have been successfully prepared by a mechanochemical activation-assisted solid-state reaction (MAS) method at 1100 °C for 2 h. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy studies demonstrated that a shrinkage in lattice parameters emerges when B-site Fe ions are substituted by Co ions. The morphology and elemental distribution were investigated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The UV-visible absorbance spectra show that LuFe0.85Co0.15O3 powders have a narrower bandgap (1.75 eV) and higher absorbance than those of LuFeO3 (2.06 eV), obviously improving the light utilization efficiency. Additionally, LuFe0.85Co0.15O3 powders represent a higher photocatalytic capacity than LuFeO3 powders and can almost completely degrade MO in 5.5 h with the assistance of oxalic acid under visible irradiation. We believe that the present study will promote the application of orthorhombic LuFeO3 in photocatalysis.