title: Preparation of γ-Fe2O3/ZnFe2O4 nanoparticles by enhancement of surface modification with NaOH.
abstract: BACKGROUND
  During liquid-phase synthesis of γ-Fe2O3 nanoparticles by chemically induced transition in FeCl2 solution, enhancement of surface modification by adding ZnCl2 was attempted by using NaOH. By using transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectrometry, and vibrating sample magnetometry, the dependence of the synthesis on the amount of additional NaOH was studied.
  
  
  RESULTS
  The experimental results show that the surface of the γ-Fe2O3 nanoparticles could be modified by adding ZnCl2 to form composite nanoparticles with γ-Fe2O3/ZnFe2O4 ferrite core coated with Zn(OH)2 and adsorbed FeCl3, and that modification could be enhanced by adding NaOH.
  
  
  CONCLUSIONS
  In the experimental conditions, when the concentration of additional NaOH was below 0.70 M, the amounts of ZnFe2O4 and Zn(OH)2 phases increased slightly and that of adsorbed FeCl3 was unchanged. When the concentration of NaOH exceeded 0.70 M, the amount of FeCl3, ZnFe2O4, and Zn(OH)2 increased.
authors.affiliation: School of Physical Science & Technology, Southwest University, Chongqing 400715, People's Republic of China.
authors.forename: Longlong
authors.initials: L
authors.lastname: Chen
authors.affiliation: School of Physical Science & Technology, Southwest University, Chongqing 400715, People's Republic of China.
authors.forename: Jian
authors.initials: J
authors.lastname: Li
authors.affiliation: School of Physical Science & Technology, Southwest University, Chongqing 400715, People's Republic of China.
authors.forename: Yueqiang
authors.initials: Y
authors.lastname: Lin
authors.affiliation: School of Physical Science & Technology, Southwest University, Chongqing 400715, People's Republic of China.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Liu
authors.affiliation: School of Physical Science & Technology, Southwest University, Chongqing 400715, People's Republic of China.
authors.forename: Junming
authors.initials: J
authors.lastname: Li
authors.affiliation: School of Physical Science & Technology, Southwest University, Chongqing 400715, People's Republic of China.
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Gong
authors.affiliation: School of Mechanical & Control Engineering, Beijing Jiaotong University, Beijing 100044, People's Republic of China.
authors.forename: Decai
authors.initials: D
authors.lastname: Li
keywords: Composite; Nanoparticles; Surface modification; ZnFe2O4; γ-Fe2O3