Synergistic impact of lanthanum and cerium co-doping ZnO for improved photocatalytic rhodamine B degradation efficiency under UV light

• Published in: Journal of molecular structure 2025-02, Vol.1322, p.140366, Article 140366
• Main Authors: Slimani, Yassine, Khan, Abuzar, Sivakumar, R., Nawaz, Muhammad, Thakur, Atul
• Format: Article
• Language: English
• Subjects: Charge carriers’ recombination; Defects; Photocatalyst; Photocatalytic degradation efficiency; Rhodamine B dye
• ISSN: 0022-2860
• DOI: 10.1016/j.molstruc.2024.140366

•Ce/La co-doped ZnO nanoparticles were prepared via sol-gel auto-ignition process.•Ce/La co-doping reduces the recombination rate of photogenerated charge carriers.•Ce/La-ZnO NPs showed high photocatalytic efficiency for rhodamine B dye degradation.•The superior photocatalytic degradation efficiency is about 99.1 % within 60 min.•The fastest degradation rate constant is 0.0762 min-1. In this study, the influence of different La and Ce co-doping amounts on the structural, morphological, optical, and photodegradation properties of ZnO nanostructures was evaluated. Zn1–2xLaxCexO nanoparticles (NPs) were prepared using sol-gel auto-ignition process, where x = 0.00 (pure ZnO), 0.01 (LC1), 0.03 (LC3), and 0.05 (LC5). The X-ray diffraction (XRD) and Raman results revealed that the prepared ZnO NPs crystallize in the hexagonal wurtzite structure. The size of crystallites is affected by the increment of La and Ce and it decreased from 24.29 nm to 10.40 nm with the increase in the concentration of La and Ce. Transmission electron microscopy (TEM) showed that the samples exhibit an irregular distribution of NPs with a dominant spherical shape morphology. The simultaneous incorporation of La and Ce in ZnO NPs led to a slight variation in the absorption edge and a slight shift in the values of the band gap energy from 3.20 to 3.24 eV. Furthermore, a reduction in the recombination rate of photogenerated charge carriers and the creation of fewer additional defects upon the appropriate insertion of Ce and La ions are highlighted by the analysis of photoluminescence spectra, Nyquist plots, and transient photocurrent measurements. The photocatalytic activity of samples was evaluated against rhodamine B organic dye under UV light irradiation. The analysis showed that LC1 sample exhibited superior photocatalytic performance with 99.1 % degradation efficiency and a degradation rate constant of 0.0762 min-1. This enhancement has been ascribed to the surface defects and the optimized crystallite size achieved, which help to generate reactive entities such as •OH and O2•− in addition to the great role of holes (h+) and impede the recombination of charge carriers e-/h+.