Enzymes may hold answer to harnessing hydrogen power

Fraser Armstrong, chemistry professor at Oxford University, said that enzymes known as hydrogenases are more effective than platinum at converting hydrogen into electrons, but the chemistry is not fully understood. So far he has only managed to create a fuel cell in his laboratory capable of powering a wrist watch -- and then only for two days -- but he hopes this might lead to bigger and better things. "If we can perfect this we might have an alternative to platinum," he told the annual meeting of the British Association for the Advancement of Science. A fuel cell converts hydrogen to electricity using a catalyst with the only byproduct being pure water. Currently, some large fuel cells are used to generate local electricity while smaller ones are used to power vehicles -- notably in Germany. Many scientists believe that hydrogen will become the fuel of the future as carbon fossil fuels run out and because it does not generate the climate warming gas carbon dioxide, but there are major problems to overcome before that happens. In the first place H2 is rarely found naturally on earth, it is highly combustible -- at concentrations of just four percent in air it becomes explosive -- and it needs a lot of electricity to produce it by splitting water into its component parts. However, if the problem of production can be overcome -- as they have done in Iceland with its plentiful supplies of cheap and clean geothermal power -- and it is rendered safe by keeping concentrations to three percent in air, then the main remaining problem is the catalyst to convert it back into power and water. To date the catalyst of choice is platinum, but the price has already doubled and there are doubts over whether in any case there is enough in the world to meet demand if fuel cells become the power source of the future. "I am convinced that hydrogen will be very important in the future as oil and gas run out. That is why my research has focused on finding enzymes to replace platinum as the catalyst," Armstrong said. "Source":[ http://www.sciam.com/article.cfm?chanID=sa003&articleID=007FF380EE5AC49FFC34442F5C2A2B86]

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