An active electrode structure is disclosed that includes fullerenes produced by conversion from a carbide. Also disclosed is an electrode that includes a fullerene covalently bonded to a carbide, the fullerene being an aligned or non-aligned array. The fullerene is included in an active electrode structure of the electrode that also includes about 50% or less non-crystalline carbon and about 5% or less of a transition metal that interferes with the ability of the active electrode structure to transfer electrons or detect an analyte. The active electrode substrate or the electrode may be included in a sensor.
