
The Hydrogen Economy
Date: Friday, December 31, 2004 @ 21:50:48 UTC Topic: General
From Physics Today Online: "...Through its reaction with oxygen, hydrogen releases energy explosively in heat engines or quietly in fuel cells to produce water as its only byproduct. Hydrogen is abundant and generously distributed throughout the world without regard for national boundaries; using it to create a hydrogen economy—a future energy system based on hydrogen and electricity—only requires technology, not political access....
...The gap between the present state of the art in hydrogen production, storage, and use and that needed for a competitive hydrogen economy is too wide to bridge in incremental advances. It will take fundamental breakthroughs of the kind that come only from basic research...
...Dramatic improvements in catalysis could lower the operating temperature of thermochemical cycles, and thus reduce the need for high−temperature materials, without losing efficiency. Molecular−level challenges, with which researchers are fast making progress using nanoscale design, include accelerating the kinetics of reactions through catalysis, separating the products at high temperature, and directing products to the next reaction step.
Bio−inspired processes offer stunning opportunities to approach the hydrogen production problem anew.6 The natural world began forming its own hydrogen economy 3 billion years ago, when it developed photosynthesis to convert CO2, water, and sunlight into hydrogen and oxygen. Plants use hydrogen to manufacture the carbohydrates in their leaves and stalks, and emit oxygen to the atmosphere for animals to breathe. Single−cell organisms such as algae and many microbes produce hydrogen efficiently at ambient temperatures by molecular−level processes. These natural mechanisms for producing hydrogen involve elaborate protein structures that have only recently been partially solved. For billions of years, for instance, plants have used a catalyst based on manganese−oxygen clusters to split water efficiently at room temperature, a process that frees protons and electrons. Likewise, bacteria use iron and nickel clusters as the active elements both for combining protons and electrons into H2 and splitting H2 into protons and electrons (see figure 2). The hope is that researchers can capitalize on nature's efficient manufacturing processes by fully understanding molecular structures and functions and then imitating them using artificial materials in such applications as fuel−cell anodes and cathodes."
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Read the whole article at: http://www.physicstoday.org/vol-57/iss-12/p39.html
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