For a series of oxidized Cu-ZSM-5 catalysts which were characterized in the catalytic amounts of the oxygen-bridged Cu2+-dimers, [Cu2+-O-Cu2+], activation energies required for the reduction of the Cu2+-dimer species by O-2 release were determined using the temperature-programmed experiments of thermal O-2 desorption (TPD) and N2O decomposition reaction. The activation energy for the thermal reduction of the Cu2+-dimers during the TPD decreased linearly with increasing molar number of the Cu2+-dimers available on the ZSM-5, suggesting that the energy barrier of the O-2 formation via a Langmuir-Hinshelwood (LH) mechanism increased in proportion to the distance between the two Cu2+-dimers in the nearest neighbor. Activation energies of thermal O-2 release were comparable to the literature-reported binding energies of the differently spaced Cu2+-dimers. It was also revealed that the activation energy of O-2 release during the temperature programmed N2O decomposition reaction over an oxidized catalyst was generally low as compared to that in the TPD, and that the degree of reduction of the Cu2+-dimers was much greater in the N2O decomposition reaction than in the TPD at the same temperatures. These beneficial effects N2O decomposition on the reduction of the Cu2+-dimers were discussed in respect of the removal mechanism of the Cu2+-dimer bridged oxygen.