In this study, α-Fe₂O₃@g-C₃N₄ photocatalyst was synthesized using an ultrasonic assisted self-assembly preparation method. The α-Fe₂O₃@g-C₃N₄ photocatalyst had a stronger optical absorption in the visible light region than pure graphitic carbon nitride (g-C₃N₄). The Z-Scheme heterojunction between α-Fe₂O₃ and g-C₃N₄ significantly inhibited the recombination of electrons and holes. The photocatalytic performances of α-Fe₂O₃@g-C₃N₄ photocatalyst were excellent in degradation of Rhodamine B (RhB) under visible light irradiation. The results indicated that 5 wt.% α-Fe₂O₃/g-C₃N₄ had the optimal photocatalytic activity because two-dimension (2D) α-Fe₂O₃ nanosheets can be well-dispersed on the surface of g-C₃N₄ layers by ultrasonic assisted treatment. A possible photocatalytic mechanism is also discussed.

Pd nanoparticles (PdNPs) stabilized by methyl cellulose (MC) were synthesized in an aqueous solution, which are monodispersed nanoparticles. PdNPs/α-Al₂O₃ catalyst was prepared with monodispersed PdNPs and showed better catalytic performance than Pd/α-Al₂O₃ catalyst prepared by the incipient wetness impregnation method using Pd(NO₃)₂ as a precursor. The catalysts were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD) and inductively coupled plasma mass spectrometry (ICP-MS). It was found that monodispersed PdNPs were spherical or elliptical nanoparticles with exposed (111) and (100) facets, and the PdNPs/α-Al₂O₃ catalyst showed a more concentrated distribution of Pd particles on the surface of α-Al₂O₃ support than the Pd/α-Al₂O₃ catalyst. The preparation method achieved the highly dispersed PdNPs/α-Al₂O₃ catalyst with smaller Pd particle size and decreased the aggregation of Pd active sites, which was responsible for higher acetylene conversion and ethylene selectivity.