磁性纳米TiO_2/SiO_2/NiFe_2O_4的制备及其催化性能

采用溶胶凝胶法制备了核壳结构磁性纳米TiO2/SiO2/NiFe2O4催化剂.利用XRD、TEM、VSM等手段对样品的粒径、晶体结构、磁性和光催化性能进行了研究.结果表明:SiO2/NiFe2O4的加入抑制了TiO2纳米粒子的生长,使晶粒尺寸减小,促进了锐钛矿相向金红石相的转变,催化剂的回收率和光催化性能均得到提高.光催化实验结果表明,当SiO2/NiFe2O4的负载量为15%时,焙烧温度为500℃时对亚甲基兰的脱色率最高.     

Microscopic Magnetic Origin of Rhombohedral Distortion in NiO

Numerous investigations have been conducted to explore the structural phase transition in antiferromagnetic 3d transition metal monoxides accompanied by appearance of magnetic phase transition. However, how the spins induce distortion in the high symmetric structure has not yet been fully understood. In this study, the monoxide Ni O is used as an example to investigate what lowers the structural symmetry. By comparing two different magnetic structures, our results reveal that the spin–lattice co...