微波辅助法合成纳米ReFeO_3光催化剂

Microwave-assisted synthesis of perovskite ReFeO_3 photocatalyst

以稀土金属硝酸盐La(NO3)3、Sm(NO3)3、Eu(NO3)3、Gd(NO3)3和Fe(NO3)3.9H2O为原材料,以活性炭为模板剂,聚乙烯醇(PVA)和尿素分别用作阻聚剂和均相沉淀剂,在微波辐照下制得纳米钙钛矿型化合物ReFeO3(Re:La,Sm,Eu,Gd)。用X射线粉末衍射仪(XRD)、UV-vis漫反射仪(DRS)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)对产物组成、结构、颗粒大小、形貌等进行了表征,结果表明产物均为单一钙钛矿结构的纳米颗粒。以产物为光催化剂,在可见光照射下对罗丹明B水溶液进行光催化降解实验,发现该类化合物均具有较好的光催化活性,180 min内对罗丹明B的脱色率均达到85%以上。

Nano-photocatalysts ReFeO3 （Re： La, Sm, Eu, Gd） were prepared by the microwave assisted method. Stoichiometric amounts of rare earth nitrate ： La （ NO3 ） 3, Sm （ NO3 ） 3, Eu （ NO3 ） 3, Gd （ NO3 ） 3 and Fe（NO3）3 · 9H2O were thoroughly mixed, active carbon was used as the template, polyvinyl alcohol （PVA） and urea were introduced as the inhibitor and the homogeneous precipitator, respectively. The whole assembly was then exposed to microwave to complete the reaction. The struetures, sizes and morphology of these samples were characterized by X-ray diffraction （XRD） , scanning electron microscopy （SEM） , transmission electron microscope （TEM） and UV-visible diffuse reflection spectroscopy （UV-vis DRS）. The results show that all the samples are nanosized perovskite-type oxides. Photocatalytie properties of these samples were evaluated by degra- dation of Rhodamine B （RhB） aqueous solution under visible light irradiation. EuFeO3, GdFeO3, SmFeO3 and LaFeO3 exhibited good photocatalytic activities. The degradation rates of RhB are all over 85% under visible light irradiation for 180 min.