Hydrogen Production From Water Under UV Radiation with Carbon Dioxide Mediation

Abstract

A simple method of hydrogen production through the decomposition of water subjected to UV radiation is presented. Water contained dissolved sodium hydroxide and the solution was saturated with carbon dioxide gas. During saturation, the pH value dropped from about 11.5 to 7-8. The produced bicarbonate and carbonate ions acted as scavengers for hydroxyl radicals, preventing recombination of hydroxyl and hydrogen radicals, and giving priority to the formation of hydrogen gas.In the presented method, the production of hydrogen is combined with the utilization of carbon dioxide.

On the Selectivity of Simultaneous CO2 and N2 Reduction Using TiO2/Carbon Sphere Photocatalysts Prepared by Microwave Treatment and Mounted on Silica Cloth

“…Additionally, the selectivity to ammonia remains high, from 95.84% for P25 to 99.57% for the P25 + 1 CS RM photocatalyst. Maintaining high levels of ammonium production and selectivity confirms the earlier suggestion [17] that the use of such a photocatalytic reactor design containing two phases of reactants and products, namely, the gas phase and water, causes the phenomenon of immediate absorption of the produced ammonia gas into the water upon the formation of the NH 4 + ion, while the ammonia formation reaction moves towards the product in equilibrium. Additionally, the presence of HCO 3 − and CO 3 2− ions in CO 2 -saturated water accelerates this process.…”

“…After drying, the prepared sample was weighed to determine the weight of the deposited photocatalyst. Then, the photocatalytic bed prepared this way was mounted inside a quartz photoreactor [17].…”

“…The experiments were carried out in a cylindrical quartz reactor with a working volume of 392 cm 3 . Its scheme has been presented elsewhere [17]. Four Actinic BL TL-E Philips lamps with a total power of 88 W were used, emitting UV-A radiation with a wavelength of 350-400 nm.…”