Abstract: The kinetic data related respectively to Ce⁴⁺anodic formation and O₂anodic evolution at PbO₂electrode in 0. 5 mol/L H₂SO₄+x mol/L Ce₂(SO₄)₃(x=0. 01-0. 10) and 0. 025 mol/L Ce₂(SO₄)₃+x mol/L H₂SO₄(x=1. 09-4. 20) solutions were obtained by the method of resolving the steady-state polarization curve. Experiments show that the anodic formation of Ce⁴⁺and O₂anodic evolution at PbO₂electrode in the mixed H₂SO₄-Ce₂(SO₄)₃solutions can be described by i(O₂)=k₁a_w⁴expβφ F/RT,i(Ce⁴⁺)=k₂a_w²[Ce³⁺]expβφF/2RT at the potential region 1.7-1.9V and by i(O₂)=k₁a_w⁴expβφF/RT, i(Ce⁴⁺)=k₂a_w²[Ce³⁺]expβφF/RT at the potential region above 1.9V (vs. SCE). On the basis of kinetics data thus obtained the mechanisms are proposed, which can be used to explain many experimental phenomena.

Key words: PbO₂anode, Anodic oxidation of Ce³⁺ion, Anodic formation of Ce⁴⁺ion, Kinet-ics and mechanism