Hydrogen (H) fuel cell technology could perhaps become the cleanest form of energy, both in terms of generating the gas and in terms of combustion products (which are just heat and water). The biggest problem has been making the process of H generation clean, efficient, and cheap, as the current, main source of H gas is coal.
But H gas can also be derived more efficiently and ecologically from the splitting of water (H2O) molecules. But here too, there is one major obstacle: the controlled (non electrical power using) process of hydrolysis (water splitting) requires a catalyst to get the reaction going. Currently, the most efficient catalyst for this is the heavy metal element Platinum. Platinum works great, except that it is a rare metal, and very expensive to mine, thus making it impractical for mass industrial usage.
In addition, hydrolysis requires two separate catalytic steps–the first (the + anode) strips away electrons from the hydrogen atoms in the water and then combines the freed Oxygen (O) atoms into molecular oxygen (02). The second step (the – cathode) allows the positively charged H atoms to acquire electrons and thus pair up into molecular hydrogen (H2). The H2 gas is then combusted (via the O2) to power the vehicle, leaving only water (and some heat) as exhaust. To make this all work cost-effectively, cleanly, and without altering the ph level of the water (which would interfere with catalysis), finding a suitable catalytic agent or agents has been the over-riding concern with fuel cell engineers
Recently, researchers at the Massachusetts Institute of Technology (MIT) reported discovery of a new, water-splitting catalyst that is far more environmentally friendly than Platinum: it’s a composite of Cobalt and Phosphorus, which are relatively inexpensive and plentiful elements. This is a “giant leap” in hydrogen fuel technology and it has many energy scientists excited and cheering.
As with every major breakthrough, the technology needs much improvement. The catalyzing system works by taking an anode made of Indium Tin Oxide (ITO) and sinking it into a solution of cobalt ions (Co4+) and potassium phosphate (KP). But this system still requires an external jolt of energy to kick in the water-splitting reaction (this energy source does not come from the stored fuel energy and is not recovered in the process). Also, the catalyst can only deal with low levels of electrical current. But researchers are still optimistic about progress with this newest approach, especially since the new catalysts are so easy to make.
On other major engineering challenge is to connect the electrodes in the cell to solar panels (that supply the external jolt to the catalytic system) to provide a clean source of energy input. Further, it needs to be shown that the catalysts can work in seawater (which is high salt/alkaline). Seawater is a cheaper and more abundant water source, and if a workable system could be devised, such a system would be able to generate H, transport it to storage cells on shore, and convert it to electricity and (fresh) water. This goes beyond merely providing a fuel source for automobiles; it could satisfy two of civilization’s most basic needs–clean, plentiful energy and clean, drinking water.
Image credit: simple H Fuel Cell diagram courtesy of the IOWA Dept. of Natural Resources
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