Rb-promoted nanocrystalline Co3O4-CeO2 catalysts were prepared by the impregnation of the Co3O4-CeO2, previously prepared using the solution combustion route, with an aqueous solution of Rb2CO3 (Rb/Co ratios 0.0125–0.20) and subsequent calcination at 500 °C. The obtained catalysts and the un-promoted Co3O4 and Co3O4-CeO2 catalysts have been characterized using XRD, FT-IR, SEM, TEM, XPS, H2-TPR and N2 physisorption techniques. The activity of the various catalysts was tested for N2O direct decomposition. All the Rb-promoted catalysts exhibited better performance than the bare Co3O4-CeO2 catalyst, where the highest activity was obtained using the catalyst with Rb/Co ratio of 0.025. The activity performance of the various catalysts was discussed in terms of the electronic properties modification accompanying the Rb-doping. For the optimum catalyst, further experiments were conducted