Catalysis of hydrogen peroxide dceomposition by 2-electron oxidation and reduction

A thermodynamical argument is used to support the suggestion made elsewhere that the more common radical chain mechanism for catalysed decomposition of H2O2 need not predominate if the catalyst can readily undergo a reversible 2-electron oxidation. How complete the exclusion of free radical formation may be depends upon the redox characteristics of the catalyst and on whether its oxidation by two single-electron steps is readily reversible along the same path.