Effective catalyst to produce oxygen for artificial synthesis

Scientists at Brookhaven National Laboratory, the US Department of Energy and the Japan Institute of Molecular Science are trying to simulate part of the complex natural photosynthesis process to produce non-polluting energies. Contaminated as hydrogen for use in energy batteries.

On March 10, 2008, on the online edition of Inorganic Chemistry, there is a forum on ' Oxygen Production ', scientists report that they can simulate the " oxidation of water oxidation " that occurs in photosynthesis. nature.

Water oxidation, a step in photosynthesis, is part of water splitting - splitting water into hydrogen and oxygen, a very complicated process. Water splitting requires a large amount of energy from sunlight and metal catalysts to activate sustainable water molecules. This process occurs in two separate ' half ' reactions: oxidation of water produces oxygen and together with protons and electrons, the protons and electrons then form hydrogen molecules.

Two Brookhaven scientists James Muckerman (left) and Etsuko Fujita.(Photo: Physorg)

According to Brookhaven chemist James Muckerman, the co-author of the work: 'Water oxidation is often thought of as a' limited 'process, which means that if it is not effectively catalyzed, it will limit the process. hydrogen production. And it is impossible to maintain hydrogen production without protons and electrons generated from water oxidation. So, to produce hydrogen from water for use in energy batteries, we have to solve the problem of creating effective but inexpensive water oxidation. '

Brookhaven chemist Etsuko Fujita explains Brookhaven's collaboration with Japanese scientists Koji Tanaka and Tohru Wada, who discovered a promising new catalyst for water oxidation in 2001. ' They I am combining theoretical and practical works to decide how the Ruthenium complex with quinine molecules catalyzes the oxidation of water to oxygen formation . '

To achieve this water oxidation reaction, Tanaka and Wada fixed the ruthenium catalyst on an electrode, placed it in a solution containing water, for an electric current to flow. As a result, the oxidation rate gives oxygen faster. The research team, including Brookhaven's Dmitry Polyansky, continues to collaborate in deeper projects to understand the details of how the catalyst works.

Scientists have discovered that when protons from two water molecules are separated by an acid reaction in solution, four electrons are converted into the receiving region of the catalyst. Once all protons are separated, the theoretical calculation predicts an oxygen-oxygen bond is formed.

What makes this catalyst ' new ' is in the majority of metal-catalysts, the electron-receiving regions are located on the metal molecule, but in the ruthenium complex the receiving region is on quione molecules. Many theoretical and practical studies need to be done to fully understand and improve the mechanism of quinone-containing catalysts.

Benefit

Producing hydrogen from water will yield more benefits than current methods, including the re-steaming of natural gas, which produces CO2 along with hydrogen. Heat from finite fuel combustion is now used to control the process of re-steaming, causing more CO ₂ as a byproduct, all of which contribute to warming. Global. Producing hydrogen from splitting water will not generate carbon dioxide in the atmosphere.

In addition, hydrogen from natural gas contains residual CO, which can ' poison ' expensive electrodes in energy batteries and require replacement. Hydrogen produced from water does not contain CO, so the electrodes are not ' poisoned '. Muckerman said: 'The ruthenium in our catalyst is still expensive, so we plan to continue our research with more economical catalysts and more economical metals.'

Hydrogen produced from water separators can also be used directly to burn in a hydrogen-based economy in the future.