Hydrogen Evolution by Plasma Electrolysis in Aqueous Solution

Abstract

Hydrogen has recently attracted attention as a possible solution to environmental and energy problems. If hydrogen should be considered an energy storage medium rather than a natural resource. However, free hydrogen does not exist on earth. Many techniques for obtaining hydrogen have been proposed. It can be reformulated from conventional hydrocarbon fuels, or obtained directly from water by electrolysis or high-temperature pyrolysis with a heat source such as a nuclear reactor. However, the efficiencies of these methods are low. The direct heating of water to sufficiently high temperatures for sustaining pyrolysis is very difficult. Pyrolysis occurs when the temperature exceeds 4000 C. Thus plasma electrolysis may be a better alternative, it is not only easier to achieve than direct heating, but also appears to produce more hydrogen than ordinary electrolysis, as predicted by Faraday's laws, which is indirect evidence that it produces very high temperatures. We also observed large amounts of free oxygen generated at the cathode, which is further evidence of direct decomposition, rather than electrolytic decomposition. To achieve the continuous generation of hydrogen with efficiencies exceeding Faraday efficiency, it is necessary to control the surface conditions of the electrode, plasma electrolysis temperature, current density and input voltage. The minimum input voltage required induce the plasma state depends on the density and temperature of the solution, it was estimated as 120 V in this study. The lowest electrolyte temperature at which plasma forms is $75 C. We have observed as much as 80 times more hydrogen generated by plasma electrolysis than by conventional electrolysis at 300 V.

The effect of electrolyte constituents on contact glow discharge electrolysis

“…It was also termed in literature as plasma electrolysis [2], electrode effects [3][4][5][6] (anode or cathode effects depending on which electrode the phenomena takes place) or contact glow discharge electrolysis (CGDE) [7][8][9]. The understanding of electrochemical discharge continued with the increasing interest for its application.…”

Production of Hydrogen-Rich Synthesis Gas by Pulsed Atmospheric Plasma Submerged in Mixture of Water with Ethanol

“…(1) represents an intensively studied process of plasma-assisted electrolysis as a more efficient alternative to the conventional electrolysis [2,20]. Both H and OH radicals from the water molecule can react with ethanol-the reaction with hydrogen atom, i.e.…”

“…Among many applications of such systems for e.g. coatings or production of nanoparticles and nanotubes a number of recent reports has been devoted to plasmachemical applications with main focus in the production of hydrogen [1][2][3][4][5]. It is interesting to note that first studies of water electrolysis and interactions of glow discharges with water solutions were described already in 1887 by Gubkin [6], followed in 1952 by Davies and Hickling [7].…”

The Cathodic Electrolytic Plasma Hardening of Steel and Cast Iron Based Automotive Camshafts

“…500 HV) of the substrates, consisting of martensitic phase of approximately 7 mm thick, after a very short treatment of 0.5 min. [2,3].…”