Hydrogen generated from sunlight and ethanol

An international team of scientists has announced success in creating hydrogen at ambient temperature and pressure using a combination of sunlight and ethanol. The team of researchers from Spain's Universitat Politècnica de Catalunya, Scotland's University of Aberdeen and New Zealand's University of Auckland say the method is potentially cheaper, produces higher yields and, because no high temperatures or pressures are required, uses less energy than conventional methods.

The process begins by placing a powdered photocatalyst and ethanol in a container, then agitating the mixture while exposing it to ultraviolet light. A titanium dioxide semiconductor within the container generates electrons when exposed to the light, and those electrons are captured by metallic gold nanoparticles in the catalyst. Those captured electrons proceed to react with the ethanol's alcohol molecules, producing hydrogen.

While the hydrogen yield depends on the amount of photocatalyst used and the size of area exposed to the light, so far the researchers have been able to produce up to 5 liters of hydrogen per kilogram of catalyst (1.32 U.S. gallons per 2.2 lbs) within in one minute. They believe that if 9 kilograms (19.84 lbs) of the catalyst were used, and the hydrogen then powered a fuel cell, 3 kW of electricity would be the result - enough, they say, to meet the needs of a typical household.

This isn't the first time that sunlight has been used to generate hydrogen. While some of those other techniques rely largely on water, the researchers claim that they also require expensive secondary materials, and that their yields haven't been as impressive. Ethanol, by contrast, is relatively inexpensive and comes from renewable plant-based sources. The photocatalyst is also said to be fairly economical, as the gold particles it contains are very small.

The team is now looking at designing reactors, that could generate hydrogen for use in providing electricity for homes.

source: gizmag