electrolysis, I did this in grade school
Fundamental Demonstration
Two leads, running from the terminals of a battery, are placed in a cup of water with a quantity of electrolyte added to establish conductivity. Hydrogen and Oxygen gases will stream from the oppositely charged electrode. Oxygen will collect at the anode and hydrogen will collect at the cathode.[/COLOR]
I don't doubt that you can break water into hydrogen and oxygen. industries do it every day and with great success. the question becomes, can you do it efficiently enough to see an increase of mpg in a vehicle without adding anything extra to it other than water?
mythbusters proved that you CAN run a car on hydrogen. the catch is that they used a hydrogen tank to provide the hydrogen (probably produced by the electrolysis method by a company that sells hydrogen gas)
but back to the theory. the theory is right and it does work, but what about the cost to produce this gas? it takes electricity which is made by the alterantor which is powered by a belt driven by the motor which uses gasoline. can you overcome the losses? that is what I am waiting to see evidence on.
Water electrolysis does not convert 100% of the electrical energy into the chemical energy of hydrogen. The process requires more extreme potentials than what would be expected based on the cell's total reversible reduction potentials. This excess potential accounts for various forms of overpotential by which the extra energy is eventually lost as heat. For a well designed cell the largest overpotential is the reaction overpotential for the four electron oxidation of water to oxygen at the anode. An effective electrocatalyst to facilitate this reaction has not been developed. Platinum alloys are the default state of the art for this oxidation. The reverse reaction, the reduction of oxygen to water, is responsible for the greatest loss of efficiency in fuel cells. Developing a cheap effective electrocatalyst for this reaction would be a great advance.
The simpler two electron reaction to produce hydrogen at the cathode can be electrocatalyzed with almost no reaction overpotential by platinum or in theory a hydrogenase enzyme. If other, less effective, materials are used for the cathode then another large overpotential must be paid.
The energy efficiency of water electrolysis varies widely with the numbers cited below on the optimistic side. Some report 50?70%[2], while the theoretical maximum efficiency of the electrolysis of water is between 80?94%.[3] These values refer only to the efficiency of converting electrical energy into hydrogen's chemical energy. The energy lost in generating the electricity is not included. For instance, when considering a power plant that converts the heat of nuclear reactions into hydrogen via electrolysis, the total efficiency may be closer to 30?45%.[[/COLOR][/COLOR]
BTW my source for this info was wikipedia = electrolysis of water (in blue)
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