With the generation of hydrogen through water splitting (the most common method for creating hydrogen) hydrogen peroxide is also formed. This is a difficult chemical to deal with and it influences the efficiency of the reaction. By controlling the spin of electrons in the reaction scientists have managed suppress the production of hydrogen peroxide.
The wide interest in hydrogen as a renewable energy is because hydrogen is high in energy, yet an engine that burns pure hydrogen produces almost no pollution, making it a strong candidate to replace fossil fuels. The main application is using hydrogen in fuel cells. Fuel cells are a promising technology for use as a source of heat and electricity for buildings, and as an electrical power source for electric motors propelling vehicles.
To improve hydrogen production and to reduce the inefficiencies associated with the generation of hydrogen peroxide, chemists from the Eindhoven University of Technology and the Weizmann Institute have focused on the spin of electrons.
Spin refers to the internal magnetic moment of the electrons involved in the oxidation reaction (the formation of oxygen, when water is split) which occurs when water is converted into hydrogen. Taking the theoretical basis that if the spins of electrons become aligned then the formation of hydrogen peroxide will not occur. This happens because the chemical state of hydrogen peroxide does not allow for two electrons with opposite spins.
Theory became reality when the researchers covered a titanium oxide anode in their photo-electrochemical cell with chiral supramolecular structures of organic paint. Chiral is a term used in chemistry to describe geometric property of some molecules and ions. A chiral molecule/ion is non-superposable on its mirror image. With the new technique the research group =managed to inject only electrons with their spins aligned in the water splitting process.
When tested out the results were successful and hydrogen peroxide formation was suppressed; achieving this lead to improved process efficiency. In terms of future application, the efficient production of hydrogen now paves the way towards water splitting by solar energy.
The research has been published in the Journal of the American Chemical Society. The research paper is headed “Control of Electrons’ Spin Eliminates Hydrogen Peroxide Formation During Water Splitting.”
