Hydrogen generation through water splitting employing cold plasma: a free radical pathway

Hydrogen, a good alternative derived from water has been claimed to replace fossil fuels since long ago. Moreover, the potentiality of H₂ has not been realized yet mainly due to storage, transportation and commercial production difficulties. H₂ formation from water vapour through plasmolysis has been considered as a potential and cleaner technique with high specific productivity and easy access, where the dielectric barrier discharge (DBD), DBD - corona hybrid plasma reactors have been employed. The online processes, which produce hydrogen efficiently eliminate the storage and other associated system issues such as operating temperature and pressure, life span of the storage material (stability), purity of hydrogen, reversibility of hydrogen uptake and release, refuelling conditions of rate and time, hydrogen delivery pressure, toxicity, overall safety, the cost, system-efficiency, etc. However, no material available presently comes close to meeting all the requirements for on board hydrogen storage. Furthermore, cost effective and environment friendly processes for efficient hydrogen production are yet getting developed. Thus, to meet such needs of ease in handling H₂ without its storage we have achieved an online option on H₂ generation through the transformation of moisture or the water splitting in Ar-moisture non thermal plasma. Two different reactors such as double-dielectric barrier discharge reactor and single-dielectric barrier surface reactor were used for H₂ generation in the study. In this presentation, the effects of gas residence time inside the plasma zone, applied voltage and frequency on the dielectric surfaces, reacting gas composition (with respect to water vapour concentrations), nature of surfaces (Pyrex and bare metal), and discharge gas-gap between two surfaces on H₂ yields will be discussed along with application of online H₂.