Novel manganese oxide particles with complex morphologies and different nanostructures (i.e., spherical/lamellar) were synthesized by initial preparation of a coordination complex of manganese with 1,4,7,10-tetraazacyclododecane (cyclen), followed by characterization of the nanostructured oxide as a catalytic material for ethanol oxidation. The samples present a bulk gamma-MnO2 structure although X-ray photoelectron spectroscopy analysis reveals that their surfaces have different chemical compositions. Some of these nanostructured particles show high catalytic activities for ethanol oxidation enabling a decrease of the reaction temperature by more than 80 degrees C as compared with traditional MnO2 particles. The high catalytic activity of the particles depends on their morphology and a relationship between morphology and specific area was established. It is proposed that these novel nanostructured manganese oxide particles may be highly active in the catalytic oxidation of other volatile organic compounds (VOCs) opening up their further development for environmental applications.