The synthesis of Pt-Ti4O7 microelectrode arrays is achieved from mixtures of TiO2 and Ti2O3 powders plus Pt particles by a thermal procedure commonly used in solid-state chemistry. Data obtained for the Pt-Ti4O7 materials by X-ray diffractometry and scanning electron microscopy are consistent with the existence of heterogeneous mixtures of Pt particles imbedded within the conductive Ti4O7 matrices. Rotated disc electrodes (RDEs) constructed from pure Pt and from the Pt-Ti4O7 materials are compared on the basis of their voltammetric and amperometric response for I- and H2O2 in 0.10M H2SO4. The observed enhancement of current densities for the Pt-Ti4O7 RDEs is rationalized on the basis of the behaviour expected for microelectrode arrays.