A comparative assessment of hydrogen production technologies and its storage

Abstract

This paper represents a review of hydrogen production systems using different methods, showing the importance and many parameters involved in producing hydrogen gas. Methodologies that are included in this review paper are water electrolysis, alkaline electrolysis, thermochemical water splitting, biomass, catalytic generation of hydrogen by ZrO2, polyethylene glycol, geothermal energy, wind energy, niobium-based photo catalyst, natural gas, artificial leaf, and biological production. Water electrolysis involves electricity breaking the water molecule into oxygen and hydrogen. A power supply is given to both positive and negative electrodes, dipped into the electrolyte and in alkaline electrolysis, an aqueous potassium hydroxide solution is used. The following method is thermo-chemical water splitting, a cycle loop of reactions with no greenhouse gas emission. It requires a high temperature to split the water molecule into oxygen and hydrogen. Biomass is a friendly method in which a low biomass concentration is used to avoid the polymerization of products. Zirconia is a catalyst used to increase the rate of gasification in biomass technology. Zirconia is also used in another method to degrade the polyethylene glycol in Inconel at high temperatures to produce hydrogen. Another reliable method used to produce hydrogen is the geothermal energy method which requires a PEM electrolyzer and is operated at a specific temperature range. The latest technology, an artificial leaf with a photovoltaic Si junction sandwiched by Co-OEC and NiMoZn catalysts, produced oxygen and hydrogen in the presence of sunlight and water after the formation of hydrogen stored in liquid and solid form by process of absorption and adsorption.