Researchers Develop Urea Electrolysis for Conversion of Urine and Urea to Hydrogen

3 July 2009

Researchers at Ohio University have developed a new technology that accomplishes the direct conversion of urine and urea to pure hydrogen via electrochemical oxidation with an inexpensive nickel catalyst.

Hydrogen production from urine. Credit: RSC. Click to enlarge.

A report on the work led by Professor Gerardine G. Botte was published in Chemical Communications, a journal of the UK Royal Society of Chemistry.

Urea—the major constituent of urine—has four hydrogen atoms per molecule ((NH₂)₂CO) which are less tightly bonded than the hydrogen atoms in water molecules. A voltage of 0.37V is required to split the molecule, compared to the 1.23V needed to split water.

During the process, urea is adsorbed on to the nickel electrode surface, which passes the electrons needed to break up the molecule. Pure hydrogen is evolved at the cathode, while nitrogen plus a trace of oxygen and hydrogen are collected at the cathode. Carbon dioxide generated during the reaction reacts with potassium hydroxide in the solution to form potassium carbonate.

Botte suggests that the technology could scale-up to produce hydrogen while cleaning up wastewater.

Resources

• Bryan K. Boggs, Rebecca L. King, Gerardine G. Botte (2009) Urea electrolysis: direct hydrogen production from urine. Chem. Commun. doi: 10.1039/b905974a

• Urine Turned into Hydrogen Fuel, Chemistry World (RSC)