Facile synthesis of cubic fluorite nano-Ce1−xZrxO2 via hydrothermal crystallization method

Nano-Ce1−xZrxO2 (x = 0.15, 0.25, 0.5) were synthesized via co-precipitation using NH4OH as precipitant and hydrothermal crystallization. The XRD results confirmed that the cubic fluorite nano-Ce1−xZrxO2 can form in NH4OH solution (pH > 10) at 150 °C for 12 h, and well crystallized 20–50 nm nano-Ce1−xZrxO2 were obtained at 200 °C for 22 h. The crystal growth of Ce1−xZrxO2 was suppressed under higher OH− concentration and crystallite size decreased with increasing concentration of NH4OH. Ce3d XP spectra showed that the main valence state of the cerium on Ce1−xZrxO2 surface is +4, and substituting Ce4+ with Zr4+ has no obvious influence on Ce3+/Ce4+ ratio.