Chemical technology news from across RSC Publishing.
The holey grail of hydrogen storage
04 December 2007
A polymer riddled with tiny pores could lead to a novel hydrogen fuel tank, say chemists in the US.
Frantisek Svec of the Lawrence Berkeley National Laboratory and colleagues at the University of California, Berkeley, made the highly porous materials from polyaniline. Svec used hypercrosslinking to give a mesh-like material with a strong affinity for hydrogen, and a high surface area.
'Using hydrogen as a CO2-free fuel is a nice idea,' said Svec. But storing the gas is complicated as the gas is 'very difficult to compress or liquefy. One alternative is to store it in materials with a very high surface area.'
The Berkeley team made the new material by adding small molecular crosslinkers to polyaniline that had been swelled in solvent. These short, rigid crosslinks hold the polymer chains apart even when the solvent is removed, leaving a material full of nanometre-scale pores. The resulting mesh had a surface area eight times higher than the best previous porous polyaniline, and a high affinity for hydrogen.
Svec agreed there is still a lot of work ahead. 'We need polyanilines with a much higher surface area - we need small pores, and a lot of them,' he said. The Berkeley team is currently trying different crosslinkers, and different reaction conditions, to increase the material's proportion of 1-2 nm pores.
James Mitchell Crow
Link to journal article
Hypercrosslinked polyanilines with nanoporous structure and high surface area: potential adsorbents for hydrogen storage
Jonathan Germain, Jean M. J. Fréchet and Frantisek Svec, J. Mater. Chem., 2007, 17, 4989
Also of interest
Hydrogen storage materials can be optimised with magnesium, say researchers in Spain.
Researchers in the UK have revealed the structure of a compound they say could have a major impact on hydrogen storage.