Structural, Magnetic Properties Of Perovskite YCo_xFe_1-xO₃ And Its Catalytic Application

YCoxFe1-xO3 (0.1≤x≤0.9) perovskite oxides were prepared by a sol-gel method for the first time with single phase. The results of X-ray and FTIR measurements indicate that YCoxFe1-xO3 belong to orthorhombic structure with Pnma space group. Detailed structural information including cell parameters, atoms position, bond lengths and angles were obtained by the Rietveld refinement method performing Fullprof program. It would be useful for the research in the future. Due to the smaller radius of cobalt ions than that of iron ions, with the doping of cobalt, the cell parameters of YCoxFe1-xO3 decrease linearly, while Fe(Co)-O bond lengths generally decrease but existing large divergence in different direction which causes the distortion of octahedral. Bond angles trend to increase with more cobalt substitution, which reduces the tilting of octahedral thus alleviates the crystal distortion.The magnetic measurements were performed by Project Process Management System (PPMS). Our results indicate that YCoxFe1-xO3 behave weak ferromagnetism when x≤0.5, while being paramagnetism when x≥0.5. Moreover, the first principle electronic structure calculations reveal that cobalt ions are in the low-spin state while iron ions are in the high-spin state. The weak ferromagnetism of YCoxFe1-xO3 perovskite should originate from the exchange interaction between Fe3+ ions similar with YFeO3, which can be ascribed to Dzyaloshinski-Moriya (DM) interaction inducing tilting of moment in the antiferromagnetic structure. Magnetic measurement also shows that there are magnetic anisotropy in YCoxFe1-xO3 (x≤0.5) and its magnetism transition temperature decreases with growing cobalt doping.Moreover, the catalytic properties of Pt/YCo0.5Fe0.5O3 are investigated. The mesoporous YCo0.5Fe0.5O3 compound was prepared utilizing SBA-15 as hard template. Then, Pt nanoparticles were supported on the YCo0.5Fe0.5O3 via an impregnation method to study its catalytic property in liquid-phase selective hydrogenation of cinamaldehyde. The results show that the catalyst of Pt nanoparticles supported on the mesoporous YCo0.5Fe0.5O3 towards the selective hydrogenation of cinnamaldehyde has the catalytic activity and selectivity of cinnamyl alcohol.