  A simple model of water nanoelectrolysis-defined as the nanolocalization at a
single point of any electrolysis phenomenon-is presented. It is based on the
electron tunneling assisted by the electric field through the thin film of
water molecules ($\sim$0.3 nm thick) at the surface of a tip-shaped
nanoelectrode (micrometric to nanometric curvature radius at the apex). By
applying, e.g., an electric potential V 1 during a finite time t 1 , and then
the potential --V 1 during the same time t 1 , we show that there are three
distinct regions in the plane (t 1 , V 1): one for the nanolocalization (at the
apex of the nanoelectrode) of the electrolysis oxidation reaction, the second
one for the nanolocalization of the reduction reaction, and the third one for
the nanolocalization of the production of bubbles. These parameters t 1 and V 1
completely control the time at which the electrolysis reaction (of oxidation or
reduction) begins, the duration of this reaction, the electrolysis current
intensity (i.e., the tunneling current), the number of produced O 2 or H 2
molecules, and the radius of the nanolocalized bubbles. The model is in good
agreement with our experiments.
