Prestige 2 spectrometer

The UV-visible absorption spectra were recorded using a (UNICAM UV 500, Thermo Electron Corporation) spectrophotometer in the range of 200–800 nm. FT-IR spectrum was recorded over the range of 4000–400 cm⁻¹ using a SHIMADZU-IR PRESTIGE-2 spectrometer. Raman spectrum was obtained using FT-Raman spectroscopy (Bruker RFS 27, USA) with laser source Nd (YAG 1064 nm) at 2 cm⁻¹ resolution. 16+ mW laser power was irradiated on rGO/Fe₃O₄ NCs to collect Raman spectrum over the wide range 4000–50 cm⁻¹. XRD patterns were recorded by PANalytical X'pert pro diffractometer at 0.02 degree per sec scan rate using Cu Kα₁ radiation (λ = 1.5406 Å, 45 kV, 40 mA). TEM images were acquired through (TEM model FEI TECNAI G2 S-Twin) at an accelerating voltage of 200 kV. The morphology of the sample was characterized using FE-SEM (FE-SEM, Zeiss Ultra-60) equipped with EDX. VSM was used to examine the magnetic property of rGO/Fe₃O₄ NCs (Lakeshore Cryotronics, Inc., Idea-VSM, model 7410, USA).

Optical properties were analyzed using UV-Vis spectrophotometers (UV-2600 SHIMADZU) and (UV-500, Thermo Electron Corporation) in the wavelength range of 200–800 nm. FT-IR spectra were recorded over the range of 4000–400 cm⁻¹ using a SHIMADZU-IR PRESTIGE-2 spectrometer. Powder XRD patterns were recorded on a PANalytical X'pert Pro diffractometer at 0.02 degree per second scan rate using CuKα₁ radiation (λ = 1.5406 Å). The morphology and elemental composition were characterized using FE-SEM (JEOL, JSM-7600F) at an accelerating voltage of 0.1 to 30 kV, equipped with EDX. The size and shape of the ZnO nanostructures were investigated by TEM (TEM model FEI TECNAI G2 S-Twin).