Elementary electrode, electrode and electrochemical detection device comprising such an electrode

An electrode comprising a plurality of elementary electrodes each having at least two characteristic dimensions which are less than 2.5 μm, said elementary electrodes each having:

• a reactive surface the characteristic dimensions of which being less than 2.5 μm,
• a thin film of catalyst, part of the surface of which is comprised in the reactive surface,
• a thin film of carbon, in an allotropic form of carbon selected from boron-doped diamond and nitrogen-doped amorphous non-hydrogenated carbon, in contact with said thin film of catalyst and having a part of its surface comprised in the reactive surface,
• a support, in contact with at least one of the thin films, enabling electrical contact to be made,
• the thin films of catalyst and of carbon being superimposed
• and the reactive surface having a three-dimensional structuring being obtained by a photolithographic etching of an upper layer to enable a lower layer to be in contact with the medium of interest, the lower layer and the upper layer being taken among the thin film of catalyst and the thin film of carbon, the support being common to the elementary electrodes and the reactive surface of the electrode consisting of the reactive surfaces of the elementary electrodes.