Structural and optoelectronic properties of Ce–Al2O3 nanoparticles prepared by sol-gel precursors

Abstract

Pure and Ce-doped Al2O3 nanoparticles (NPs) were synthesized in different cerium percentages of 1%, 2%, and 3% by cerium chloride and aluminum nitrate precursors in the presence of powerful reducing agent-NaBH4 and CTAB stabilizers using sol-gel method. To examine the crystal, morphological, optical, and electronic properties, the XRD, FESEM, TEM, FTIR, UV-DRS, and PL analyses were used for the heated samples in 1000 °C for 4 h. The XRD analysis indicated that the pure sample has γ, δ and θ phases, and the structure remained unchanged when Ce impurity was increased. The EDS analysis showed that the percentage of Al element was 47.40 wt% in the pure sample and that it increased to 53.83 wt% for 1% doped sample increasing Al ions in tetrahedral and octahedral sites of alumina through increasing Ce impurities. The TEM results revealed the sphere-like particles with mean particle size of 26 nm in diameter at a 3% level of impurity. The FTIR result showed that an increase in AlO4 adsorption peak in 821 cm−1 compared to AlO6 adsorption peak in 619 cm−1 was due to the dominance of vibrating bonds of tetrahedral sites rather than octahedral sites in alumina. The optical UV-DRS analysis also demonstrated the redshift configuration in a sample by increasing Ce dopant and reducing energy bandgap from 4.10 to 3.26 eV for pure and 3% Ce-doped Al2O3 NPs, respectively. Finally, the photoluminescence (PL) results indicated that increasing Ce dopant reduced electron-hole recombination leading to an increase in photocatalytic activity.