[ferretman25]

The iodine clock reaction involves 2 equations:

1. H₂O₂ (aq) + 2I^-(aq)+ 2H⁺(aq) → 2H₂O(l) + I₂ (aq)
2. I₂ (aq) + 2S₂O₃^2-(aq) → 2I^-(aq) + S4O62-(aq)

Adding a solution of MoO₄ catalyses the first reaction by providing an alternative pathway with a lower activation energy - 43 kJ/mol as compared to 52 kJ/mol in the uncatalysed reaction. What specifically is this 'alternative pathway' and in full detail, how does the MoO₂ speed up the reaction rate of the first reaction?

[AWK]

Some transition metals form many oxides with an interesting structure that are good catalysts for oxidation reactions, e.g. https://pubs.rsc.org/en/content/articlelanding/2011/dt/c0dt00706d/unauth#!divAbstract