Fig. 3.

The stages of the nanoceria interaction with oxidant and water molecule. a Double-oxidized Ce⁴⁺–${\mathrm{V}}_{\mathrm{O}}^{++}$–Ce⁴⁺ site and single-oxidized Ce⁴⁺–${\mathrm{V}}_{\mathrm{O}}^{+}$–Ce³⁺ site on nanoceria surface and their interaction with H₂O molecule. b Regeneration of Ce³⁺–V_O–Ce³⁺ site for next oxidation cycle