稀土铁酸盐的制备及光催化性能

Preparation and photocatalytic property of rare earth ferrites

在600℃温度下热分解配位前驱体,制备出5种稀土铁酸盐颗粒(ReFeO_(3),Re=Y^(3+)、La^(3+)、Sm^(3+)、Gd^(3+)和Ho^(3+))。采用XRD、SEM、Uv-Vis DRS以及VSM等手段对所制备产物进行物相、表面形貌、能带结构以及磁性能等进行表征。XRD表明,含Y^(3+)、La^(3+)和Gd^(3+)的前驱体灼烧后产物为单相正交晶系的ReFeO_(3),而Sm^(3+)和Ho^(3+)的前驱体灼烧后产物则是由ReFeO_(3)和微量的稀土氧化物Re2O_(3)两相构成的复合物。DRS结果反映,所有灼烧产物从紫外区到可见区对光都有比较强的相应,能带结构有轻微差异。VSM结果显示,所有产物均具有一定的弱铁磁性,其中HoFeO_(3)的磁性最强,磁参数分别为:H_(c)=28656 A/m,M_(s)=0.286 Am^(2)/kg,M_(r)=0.076 Am^(2)/kg。同时用MO作为光降解模型,研究产物的光催化活性。MO降解结果显示,所有产物对MO光降解都具有良好的催化性,其中YFeO_(3)展现更强的催化效果,MO在其作用下,光照4h的降解率达86%。

Five rare earth ferrites of ReFeO_(3)(Re=Y^(3+),La^(3+),Sm^(3+),Gd^(3+)and Ho^(3+))are prepared through thermal decomposition coordination precursor at the temperature of 600℃with diethylenetriaminepentaacetic acid(H5dtpa)as ligand.The phase,morphology,band structure and magnetic property of samples prepared are characterized by XRD,SEM,Uv-Vis DRS and VSM.XRD results show that as-prepared products including Y^(3+),La^(3+)and Gd^(3+),respectively,are only the phase of orthorhombic ReFeO_(3),while the samples including Sm^(3+),Ho^(3+),respectively,are composed of principal ReFeO_(3)and a trance amount of Re2O_(3).The band gap of Eg is about 2.0 eV for all products,exhibiting strong response to light from ultraviolet region to visible region.All products show weak magnetism,and HoFeO_(3)exhibits relatively strong magnetism with H_(c)=28656 A/m,M_(s)=0.286 Am^(2)/kg and M_(r)=0.076 Am^(2)/kg.Moreover,catalytic activity for all samples prepared is studied based on the degradation of MO resolution.From result of degradation rate of MO,it can be seen that all samples prepared exhibit good photcatalytic activity.Among them,YFeO_(3)displays better photo-catalytic activity,and 86%of MO is degraded under light irrational time of 4 h in the present of it.