NiO and Ag–Cd co-doped NiO nanoparticles: study of photocatalytic degradation of rhodamine B dye for wastewater treatment

• Published in: International journal of environmental science and technology (Tehran) 2023-02, Vol.20 (2), p.2021-2036
• Main Authors: Shakil, M., Inayat, Usama, Tanveer, M., Nabi, G., Gillani, S. S. A., Rafique, M., Tariq, N. H., Shah, A., Mahmood, A.
• Format: Article
• Language: English
• Subjects: Aquatic Pollution; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Science and Engineering; Original Paper; Soil Science & Conservation; Waste Water Technology; Water Management; Water Pollution Control
• ISSN: 1735-1472; 1735-2630
• DOI: 10.1007/s13762-022-04101-2

For the first time, NiO and Ag–Cd co-doped NiO Cd x Ag 0.30 Ni 0.70−x O ( X  = 0.0, 0.05, 0.10, and 0.15) have been synthesized through a facile sol–gel method to investigate the photocatalytic performance by visible-light-driven degradation of rhodamine B dye for wastewater treatment. All samples were characterized through X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray, Fourier transform infrared, photoluminescence, and ultraviolet–visible spectroscopy for structural, morphological, elemental, functional groups, optical, and bandgap analysis, respectively. Face-centered cubic structure of NiO was confirmed through X-ray diffraction. The formation of NiO and Ag–Cd co-doped NiO nanoparticles was confirmed through elemental and functional groups analysis. Optical properties obtained from photoluminescence spectroscopy revealed visible-light emission spectrum and slower electron/hole pair recombination rate with an increase in doping. Minimum optical bandgap energy of 2.37 eV was found for the Cd 0.15 Ag 0.30 Ni 0.55 O sample. Photocatalytic performance study revealed that degradation followed first-order kinetics. Cd 0.15 Ag 0.30 Ni 0.55 O was the best sample which showed the maximum efficiency of 97%, the reaction rate constant K (min −1 ) of 0.0496, and the correlation coefficient ( R 2 ) of 0.988 after 140-min degradation of rhodamine B dye. The reusability and stability of the best sample were checked for six cycles by obtaining an X-ray diffraction pattern after the photocatalytic process.