Berlin, May 8 : Scientists have succeeded in the controlled extraction of hydrogen from formic acid-without the need for the high-temperature reforming process usually involved in other hydrogen generation systems.
This hydrogen source, generated at room temperature, can be directly introduced into fuel cells.
According to a report in the journal Angewandte Chemie, the scientists who successfully carried out the process were Bjorn Loges, Albert Boddien, Henrik Junge, and Matthias Beller from the Leibniz Institute of Catalysis in Rostock.
Hydrogen-powered fuel cells are the cleanest source of energy because they only produce one type of exhaust gas: water vapor.
However, it is not yet practicable to transport and store hydrogen, which is a gas and cannot be pumped into a tank as easily as gasoline.
Storage systems currently in use are large and heavy, expensive, and complex. It would thus be better to couple the fuel cell directly to a hydrogen-producing material, which would supply the fuel cell on demand.
The researchers from Rostock have now developed a feasible process for the on-demand release of hydrogen; they produce hydrogen from formic acid (HCO2H).
In the presence of an amine and with a suitable catalyst (e.g. the commercially available ruthenium phosphine complex, formic acid is selectively converted into carbon dioxide and hydrogen at room temperature.
A simple activated charcoal filter is enough to purify the hydrogen gas for use in a fuel cell.
The use of formic acid for "hydrogen storage" allows the advantages of established hydrogen/oxygen fuel cell technology to be combined with those of liquid fuels.
Formic acid is nontoxic and easy to store. Because formic acid can be generated catalytically from CO2 and biomass-derived hydrogen, the cycle is CO2 neutral in principle.
As for the possibilities of replacing gasoline with formic acid in the future, Bellar said that it is not inconceivable, but initial applications requiring smaller amounts of energy are more probable.
"For the use of fuel cells in portable electrical devices, this nascent formic acid technology opens up new possibilities in the short term," said Beller.