A model for the homogeneous kinetic oscillations in the CO oxidation on Pt(100) is extended to describe space dependent situations by the introduction of two diffusive-like processes. As is well known these increase the size of the instability domain. Depending on the values of the diffusion coefficients, they lead to the existence, when the surface is homogeneous, of stationary periodic space patterns besides the uniform oscillating solutions. This may be shown both theoretically through linear stability analysis or numerical computation.