Polyol-assisted hydrothermal synthesis of Mn-doped α - Fe2O3(MFO) nanostructures: Spin disorder-induced magnetism and photocatalytic properties

Hierarchical nanostructures play an important role in environmental clean-up and sustainability applications. The magnetic and photocatalytic characteristics of flower-like Mn-doped α-Fe₂O₃ nanostructures were prepared by using a polyol-assisted hydrothermal method. Crystallite sizes are in the range of 35-42 nm, and the existence of 3D hierarchical nanostructures was observed in FESEM pictures. The optical band gap energy varies between 2.08 and 2.16 eV, while XPS examination exposes the ions' charge states and validates Mn³⁺ inclusion in the Fe³⁺ lattice. At room temperature, the addition of Mn to α-Fe₂O₃ results in a spin disorder ferromagnetism and coercivity of about 600 Oe was achieved. Methylene blue (MB) dye solution degraded by 92% when 2.5% Mn doped with α-Fe₂O₃ under visible conditions for 120 min irradiation time.

Mesocrystalline Zn-Doped Fe3O4 Hollow Submicrospheres: Formation Mechanism and Enhanced Photo-Fenton Catalytic Performance

Uniform and magnetic recyclable mesocrystalline Zn-doped Fe₃O₄ hollow submicrospheres (HSMSs) were successfully synthesized via a simple one-pot solvothermal route and were used for efficient heterogeneous photo-Fenton catalyst. XRD, XPS, Raman spectroscopy, Mössbauer spectroscopy, SEM, HRTEM, and EDX analyses revealed that the shell of HSMSs is highly porous and assembled by oriented attachment of magnetite nanocrystal building blocks with Zn-rich surfaces. Furthermore, a possible formation mechanism of mesocrystalline hollow materials was proposed. First, Fe₃O₄ mesocrystals were assembled by oriented nanocrystals, and a Zn-rich amorphous shell grew on the surfaces. Then, Zn gradually diffused into Fe₃O₄ crystals to form Zn-doped Fe₃O₄ due to the Kirkendall effect with increasing the reaction time. Meanwhile, the inner nanocrystals would be dissolved, and outer particles would grow larger owing to the Ostwald ripening process, leading to the formation of a hollow structure with porous shell. The Zn-doped Fe₃O₄ HSMSs exhibited high and stable photo-Fenton activity for degradation of rhodamine B (RhB) and cephalexin under visible-light irradiation in the presence of H₂O₂, which results from their hollow mesocrystal structure and Zn doping. It could be easily separated and reused by an external magnetic field. The results suggested that the as-obtained magnetite hollow mesocrystals could be a promising catalyst in the photo-Fenton process.

Fe-doped CeO2 nanorods for enhanced peroxidase-like activity and their application towards glucose detection

Surface defects of Fe-doped CeO₂ nanorods were found to be active sites for increasing peroxidase mimetic activity.

Graphene-supported binary active Mn0.25Co0.75O solid solution derived from a CoMn-layered double hydroxide precursor for highly improved lithium storage

Graphene-supported binary active solid solution (Mn_0.25Co_0.75O) is derived from CoMn-layered double hydroxide/graphene oxide precursor. Electrochemical test shows the highly improved electrochemical performances of the composite.

High interfacial lithium storage capability of hollow porous Mn2O3 nanostructures obtained from carbonate precursors

Porous Mn₂O₃ boxes present an upward trend of reversible capacity assigned to the gradually emerging contribution of interfacial storage.