2.3 Characterization method
crystal phases of Fe3O4@LDHs were determined by a D8ADVANCE X-ray diffractometer (Bruker Corporation, Germany) using Cu K radiation. Fourier transform infrared (FTIR) spectra were collected on a Vertex 70 FTIR spectrophotometer (Bruker Corporation, Germany) using transmission model. A hitachi-800 transmission electron microscope (TEM) was measured on morphology and structure. the magnetization was measured on a 7410 vibrating sample magnetometer (VSM)