Easy way to produce hydrogen as a fuel
scientistshave found a way to use solar energy to extract zinc metal, which readily reacts with water to produce hydrogen. With some improvements, the process can be used to produce hydrogen for vehicles powered with fuel cells that would emit just water.
Researchers at the Weizmann Institute of Science in Rehovot, Israel, used 64 seven-metre-wide mirrors to focus sunlight onto a tower containing the mineral zinc oxide and charcoal. The solar energy heated the chemical reactor to 1,200 c and yielded up to 50 kilogrammes of zinc per hour. Team member Michael Epstein said similar plants could be set up all over the Mediterranean region to produce zinc, which could also be used in batteries, says a Nature News Service report.
The methods commonly used to produce hydrogen require either the fossil fuels they purport to replace, or water-splitting technology that has low efficiency. It has long been known that metals such as zinc can release hydrogen from water. But purifying the metal is the hard part. The traditional method of obtaining zinc involves many chemical steps and huge amounts of electricity.
The process evolved isn't yet fully clean, environmentally. While zinc is produced, the reaction also releases carbon monoxide (from the charcoal), which eventually turns into carbon dioxide, a greenhouse gas. The scientists claim in a full-scale industrial process, the carbon monoxide could be used to produce more hydrogen from water.
For now, the process produces as much carbon dioxide as extracting the same amount of hydrogen from natural gas, Epstein says. But, he adds, the carbon in his reaction is a renewable resource rather than a fossil fuel.
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