*2.2. Characterizations*

Structural study of prepared samples was carried out by Rigaku X-ray Diffractometer (XRD) (installed at DCRUST, Murthal, India) as Cu Kα radiation source with wavelength 1.54 Å. The size and surface morphology of prepared nanoparticles were studied using Thermo Scientific Talos Cryo TEM (installed at AIIMS, New Delhi). Raman spectra were recorded with a STR 500 Confocal Micro Raman Spectrometer (DPSS Laser of wavelength of 532 nm at 12.5 MW power source) (installed at

MNIT, Jaipur, India). Fourier transform infrared spectroscopy (FTIR) was explored by a NICOLET 5700 (present at DCRUST, Murthal, India) with transmittance in the range 400–4000 cm−<sup>1</sup> . Dielectric measurements were done using Novacontrol broadband (installed at Delhi University) impedance at room temperature to measure complex dielectric permittivity and tangent loss. UV-Vis absorption spectra were recorded at different time intervals to monitor the degradation process using LABINDIA UV 3092 UV-VIS spectrophotometer (present at DCRUST, Murthal, India). 5700 (present at DCRUST, Murthal, India) with transmittance in the range 400–4000 cm−<sup>1</sup> . Dielectric measurements were done using Novacontrol broadband (installed at Delhi University) impedance at room temperature to measure complex dielectric permittivity and tangent loss. UV-Vis absorption spectra were recorded at different time intervals to monitor the degradation process using LABINDIA UV 3092 UV-VIS spectrophotometer (present at DCRUST, Murthal, India).

*Crystals* **2020**, *10*, x FOR PEER REVIEW 3 of 19

TEM (installed at AIIMS, New Delhi). Raman spectra were recorded with a STR 500 Confocal Micro

MNIT, Jaipur, India). Fourier transform infrared spectroscopy (FTIR) was explored by a NICOLET

#### *2.3. Photocatalytic Test 2.3. Photocatalytic Test*

Photocatalytic performance of Zn doped α-Fe2O<sup>3</sup> samples were investigated by decomposition of Rose bengal (RB) dye using 300 W UV light source having 365 nm wavelength at room temperature which is shown in Figure 1. In this experiment, 0.05 g of catalyst was sprinkled in 50 mL of 5 ppm RB dye solution and vigorously stirred for 45 min in the dark to achieve equilibrium adsorption/desorption at the surface of photocatalyst. Then, the dye solution was continuously stirred throughout the experiment under UV light and 3 mL of solution was collected at regular 15 min time intervals to monitor the degradation process using UV-VIS spectrophotometer. Photocatalytic performance of Zn doped α-Fe2O<sup>3</sup> samples were investigated by decomposition of Rose bengal (RB) dye using 300 W UV light source having 365 nm wavelength at room temperature which is shown in Figure 1. In this experiment, 0.05 g of catalyst was sprinkled in 50 mL of 5 ppm RB dye solution and vigorously stirred for 45 min in the dark to achieve equilibrium adsorption/desorption at the surface of photocatalyst. Then, the dye solution was continuously stirred throughout the experiment under UV light and 3 mL of solution was collected at regular 15 min time intervals to monitor the degradation process using UV-VIS spectrophotometer.

**Figure 1.** Schematic representation of synthesis and photocatalytic test of pure Fe2O3, Zn 2%, Zn 4% and Zn 6% nanoparticles. **Figure 1.** Schematic representation of synthesis and photocatalytic test of pure Fe2O<sup>3</sup> , Zn 2%, Zn 4% and Zn 6% nanoparticles.
