Ozone in the stratosphere can be destroyed through the following three-step mechanism that occurs in the presence of chlorine atoms.
Step 1 (fast): Cl(g) + O3(g) → ClO(g) + O2(g)
Step 2 (slow): ClO(g) + ClO(g) → Cl2O2(g)
Step 3 (fast): Cl2O2(g) + hν → 2 Cl(g) + O2(g)
Based on this mechanism, which species functions as the catalyst for the overall conversion of O3 to O2?
a) ClO(g)
b) O2(g)
c) Cl(g)
d) Cl2O2(g)