ZnFe2O4（ZFO） was synthesized via a sol-gel method firstly, then the ZFO was irradiated with microwave treatment to obtain M-ZFO using NH4C1 as dispersant for 10 min to improve the photocatalytic activity. Large par- tides of ZFO were broken into small and uniform particles by the gases of hydrogen chlorine and ammonia during the decomposition of NH4Cl. Compared to ZnFe2O4 without microwave treatment（ZFO）, M-ZFO exhibits smaller particle size, higher surface area and larger saturation magnetization. More importantly, the photocatalytic activity of M-ZFO for methylene blue was increased by 25% compared with that of ZFO.
FENG Jing WANG Yuting ZOU Linyi LI Bowen HE Xiaofeng Lü Shengna CHEN Tingting
Large scale NiFe2O4 nanowires were synthesized with NiO nanosheets as precursor by means of the topochemical solid state method. The morphologies and magnetic properties of NiFe2O4 annealed at different temperatures were studied. An appropriate annealing temperature was requested to transfer NiO nanosheets and Feions into NiFe2O4 nanowires. In the beginning stage of synthesizing process, the shape ofNiO nanosheets remained unchanged at low temperatures. And then, NiO nanosheets split into nanowires from 400 ℃ to 600 ℃. At last they transformed into nanoparticles from 700 ℃ to 1000 ℃. Thus, the optimized annealing temperature was selected as 600 ℃ because the NiFe2O4 obtained at 600 ℃（N600） exhibited a maximum aspect ratio of 50 with a diameter of 20 nm and a length of 1 μm. Furthermore, N600 also displayed the largest magnetization value of 26.86 A·m^2/kg and the lowest coercivity（Hc） of 8914 A/m.
