Efficient CoFe2O4/CeO2 nanocomposites for photocatalytic dye degradation

Cobalt ferrite/cerium oxide (CoFe2O4/CeO2) nanocomposites with varying weight ratios (1:1, 1:2, 1:3, and 1:4) were synthesized by hydrothermal method and explored for the removal of Rose Bengal dye by photocatalytic activity. XRD analysis of synthesized nanocomposites revealed two different phases corresponding to CoFe2O4 and CeO2. An increase in CeO2 content [from CoFe2O4/CeO2 (1:1) to CoFe2O4/CeO2 (1:4)] is responsible for the creation of large number of oxygen vacancies and photoinduced electrons and holes. FTIR spectra depicted different chemical groups/bonds i.e., Co–O, Fe–O, and O–Ce–O present in the system. Raman spectra demonstrated the highest peaks at 461 and 692 cm−1 which confirmed the stretching behavior of Ce–O mode for CeO2 and A1g mode of ferrites, respectively. Furthermore, VSM analysis showed a reduction in magnetization from 22.3 emu g−1 for 1:1 to 5.9 emu g−1 (1:4). The creation of new sub-band energy levels was responsible for an increase in band gap from 2.74 to 2.93 eV demonstrated by UV-DRS spectroscopy. The synthesized nanocomposite [CoFe2O4/CeO2 (1:4)] exhibited 89% degradation of Rose Bengal dye in 75 min. It is undoubtedly proven that accompanying the oxygen vacancies originating from Ce3+ to Ce4+, increased lattice parameters and formation of p–n heterojunction are responsible for enhanced photocatalytic activity of the material.