Synthesis, Characterization, and Electrochemical Properties of La-Doped α-Fe2O3 Nanoparticles

La-doped alpha-Fe2O3 nanoparticles were synthesized by a hydrothermal method. The effects of pH value on the morphology, structure, and electrochemical stability of the La-doped alpha-Fe2O3 nanoparticles were investigated by X-ray diffraction, transmission electron microscopy, Fourier-transform infrared spectrum, and electrochemical methods. The results show that the La-doped alpha-Fe2O3 nanoparticles exhibit a uniform spherical morphology at pH = 6, and are agglomerated with a poor dispersion at pH = 4 and 8. The iron oxide lattice is distorted by the La-doping, which increases the Fe-O bond strength. The decreased Fe-O bond length and the increased Fe-O bond energy at pH = 6 improve the electrochemical stability of alpha-Fe2O3. The waterborne coating modified with La-doped alpha-Fe2O3 nanoparticles exhibits a steady corrosion resistance.