Development and characterization of CeO2 polishing powder: Calculation of microstructure parameters using XRD profile analysis and its heterogeneous Fenton-like oxidation process investigation

Abstract

To develop a semiconductor Fenton-like oxidation process, CeO₂ polishing powder (labelled as CP-2) was explored as heterogeneous Fenton-like catalyst for the degradation of Neutral red phenazine dye in aqueous solution. A comparative study of various microstructural properties of nanoscale CP-2 were explicitly determined by XRD profile analysis using a variety of XRD models. The powdered material CP-2 was deeply analyzed using SEM, FT-IR, UV–vis-DRS and surface charge (pH_PZC) technique. From the physical properties analysis, CP-2 powder exhibited three classes of the cumulative particle size distribution i.e. D₅₀ of 1.35 µm, D₁₀ of 0.61 µm and D₉₀ of 6.21 µm, corroborating its polycrystallinity nature (CeO₂ = 65 ± 5%, La₂O₃: 35 ± 5% and Pr₂O₃ ≤ 5%). XRD results revealed the formation of the LaCeOx substitution solid solution with the preservation of the crystalized cubic fluorite-type CeO₂ phase. All the stated models demonstrated an acceptable crystallite size range of 26–32 nm. In comparison with SSP method, UD, UDED and H-W models displayed a minimal of microstrain (ε≈0.00011), trivial strains, defects and size-shape anisotropy in the CP-2 environment, while SSP method exhibited the highest intrinsic strain (ε = 0.0184) accredited to the lattice dislocations. Functional groups, especially the Ce–O and La–O bondings and Ce³⁺ electronic transition were corroborated by the FT-IR informations. SEM analysis showed randomly and irregularly shaped cluster of variable dimensions in the range of 715 nm-4.52 µm and 2.11–4.52 μm, respectively.The optical band gap of 3.0 eV and the pHpzc of 6.6 were obtained for CP-2 NPs. Ultimately, the the decomposition of H₂O₂ over CP-2 NPs is more sensitive to the pH parameter. The heterogeneous Fenton-like oxidation process (NR/ H₂O₂/CP-2 sytem: 85.90% degradation) was synergetically enhanced within 60 min, outperforming the homogeneous (NR/H₂O₂ process: 12.60%) and surface adsorption (NR/CP-2 system: 67.36%). Experimental kinetic study was correlated with the Langmuir–Hinshelwood kinetic model for pseudo first order reaction (R² = 0.70–0.92 and 0.56–0.86 for various degradation processes and pH solution, respectively). Consequently, the outstanding degradation of NR could be can be synergysticaly explained by the heterogeneous Fenton-like oxidation mechanism through the generation of the ROS (^•OH/¹O₂ and OVs).These ROS-induced Fenton-like reaction in H₂O₂/CP-2 system, acting as strong oxidative species, could be primary factors in the RN eradication into harmless byproducts (CO₂, H₂O and NO₃⁻ etc.). Thus, H₂O₂/CP-2 catalystic system may be regarded as a sustainable option for destroying organic dye pollutants in aqueous solutions. Overall, the present results are expected to offer a potentially substantial reference for the quantitative and qualitative analysis of nanamaterial oxide.