Raman spectroscopy and shadowgraph visualization of excess protons in high-voltage electrolysis of pure water

In a horizontal electrohydrodynamic bridge experiment, protons are created at the anode via high-voltage electrolysis. The hydrated protons can be observed both optically using shadowgraphy and Raman spectroscopy. If the system is taken out of its electrochemical equilibrium by a sudden disruption of the bridge, excess protons remain in the anolyte. These protons are observed via an enhancement of solvated protons and their accumulation at the liquid surface, causing a residual electric field of several kV/m and a reduction of surface tension by a few mN/m as they accumulate at and escape through the surface.