Consider the following three-step mechanism occurring in basic solution.
Step 1 ClO⁻ + H₂O₂ → HOCl + HO₂⁻
Step 2 HO₂⁻ + IO₃⁻ → IO₂⁻ + O₂ + OH⁻
Step 3 IO₂⁻ + HOCl → IO₃⁻ + Cl⁻ + H⁺
Identify the catalyst in the mechanism and justify your answer in one or two sentences.