Scientists have produced hydrogen by accelerating a natural process found in rocks deep below the Earth's surface, a short-cut that may herald the wider use of what is a clean fuel, a study showed on Sunday.

 

Used in rockets and in battery-like fuel cells, hydrogen is being widely researched as a non-polluting fuel, but its use is so far hampered by high costs. A few hydrogen vehicles are already on the roads, such as the Honda FXC Clarity and Mercedes-Benz F-Cell, and more are planned.

 

Researchers in France said aluminum oxide speeded up a process by which hydrogen is produced naturally when water meets olivine, a common type of rock, under the high temperatures and pressures found at great depths.

 

"We have overcome a preliminary step for a carbon-free energy production," lead researcher Muriel Andreani of the University Claude Bernard Lyon 1 in France told Reuters.

 

The addition of aluminum oxide accelerated the natural process by between 7 and 50 times, using temperatures of between 200 and 300 degrees Celsius (400-570 Fahrenheit) at a pressure equivalent to twice the depth of the deepest ocean.

 

In the process, olivine turns into the mineral serpentine and water splits into its components, hydrogen and oxygen.

 

Currently, the most widely used technology for producing hydrogen - separating it from natural gas - requires far higher temperatures of 700 degrees Celsius (1,300 Fahrenheit) and releases heat-trapping carbon dioxide as a by-product.

 

Using lower temperatures would save energy and money.