Narrow Results

Based on the first-principles method of density functional theory and the transition state theory, the adsorption, occupancy and diffusion behaviors of H atoms in LaFeO₃(010) surface with O vacancy are investigated. It is found that, for the LaFeO₃(010) surface with O vacancy, the H atom prefers to adsorb on the O atom and also could adsorb on the Fe atom; the adsorption energy of H atom in the surface layer is the biggest, while the adsorption energy decreases with the H atom in-depth diffusion to the bulk; the diffusion of H atoms from the surface layer to the bulk phase is a process of progressive rotation around the O atom, and the stepwise diffusion is more likely to occur than the direct diffusion. If the H atom can cross the barrier and diffuse from the surface to the subsurface, it will be more likely to diffuse inward. The presence of O vacancy can reduce the barrier for H atoms diffusion from the surface to the subsurface, and then improve the diffusion properties of the LaFeO₃(010) surface system.

In this study, LaFeO₃/ZnIn₂S₄ composites were synthesized via in situ synthesis. The composition, structure and optical absorption properties of LaFeO₃/ZnIn₂S₄ were characterized by X-ray diffraction (XRD), ultraviolet-visible diffuse reflectance spectroscopy, fluorescence spectroscopy (PL), Fourier Transform infrared spectroscopy (FT-IR) and field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The photocatalytic activity of the LaFeO₃/ZnIn₂S₄ photocatalyst was determined based on the degradation of methyl orange (MO). LaFeO₃/ZnIn₂S₄ composites showed much better photocatalytic performance compared with pure LaFeO₃ and ZnIn₂S₄. The enhanced photocatalytic performance was attributed to intimately contacted interfaces and charge transfer channels which can effectively transfer and separate the photogenerated charge carriers.

A single-crystalline, crack-free, epitaxial (100)_cLaFeO₃ films were in situ grown by pulsed laser deposition on (100) SrTiO₃ substrates. X-ray diffraction, atomic force microscopy and transmission electron microscopy reveal that the LaFeO₃ films have high crystalline quality, a very smooth surface, and an atomically sharp LaFeO₃/SrTiO₃ interface. The magnetic properties of the LaFeO₃ films were obtained by a superconducting quantum interference device magnetometry. The saturated magnetization and coercive field of LaFeO₃ films are 14 emu/cm³ and 600 Oe, respectively.