Ce1-x O₂Cux Nanoparticles: Synthesis, Characterization and Catalytic Activity for Phenol Degradation.

Abstract

Solid solutions of CuO in CeO₂ have been prepared by the solution combustion method. This method allows the Cu2+ ions to dissolve into CeO₂ lattice instead of Ce4+ ions. This creates charge imbalance and lattice distortion in CeO₂ because of which oxygen vacancies are produced. The presence of Cu in ceria causes decrease in lattice parameters, smaller crystallites, and larger surface area. Both techniques XRD and Raman spectroscopy confirm the presence of cubic phase of CeO₂ with fluorite structure and they also show a peak shift after the introduction of Cu which is an indication of the total symmetry breaking of ceria structure. This may be related with the partial substitution of Ce4+ by Cu2+ cations in the CeO₂ lattice. TEM analysis results provide an average size of 27.4 nm for Cu-doped CeO₂ particles. XPS confirms the Cu2+ species in Cu-doped sample. The prepared Cu-Ce materials are explored for phenol degradation. The effect of initial phenol concentration, pH and catalyst amount on phenol degradation is investigated. It is observed that with increase in an initial phenol concentration, the degradation efficiency decreased. The maximum degradation efficiency is observed at pH 3 and 0.5 g/L amount of Cu-doped CeO₂ catalyst.