If I understand correctly, the role of such a catalyst is to reduce activation energy, thus bringing the reaction's energy consumption closer to its theoretical minimum, see e.g. :
http://en.wikipedia.org/wiki/Electrocatalyst << An electrocatalyst is a catalyst that participates in electrochemical reaction. Catalyst materials modify and increase the rate of chemical reactions without being consumed in the process. Electrocatalysts are a specific form of catalysts that function at electrode surfaces or may be the electrode surface itself. ... One of the greatest drawbacks to galvanic cells like fuel cells and various forms of electrolytic cells is that they can suffer from high activation barriers. The energy diverted to overcome these activation barriers is transformed into heat. In most exothermic combustion reactions this heat would simply propagate the reaction catalytically. In a redox reaction, this heat is a useless byproduct lost to the system. The extra energy required to overcome kinetic barriers is usually described in terms of low faradayic efficiency and high overpotentials. ... Like other catalysts, an electrocatalyst lowers the activation energy for a reaction without altering the reaction equilibrium. Electrocatalysts go a step further then other catalysts by lowering the excess energy consumed by a redox reaction's activation barriers. >> Michel 2010/5/6 <[email protected]>: ... > BTW the most important part of the article is the phrase: > > "....to further facilitate electrical charge-driven as well as light-driven > catalytic processes." > > IOW the Hydrogen is obtained either through electrolysis or via the action of > sunlight directly, which means that the energy still has to come from > somewhere. > > However a further interesting point is that Mo is also a Mills catalyst, which > may go some way toward explaining why it is so active in this role. > > Perhaps if they do careful measurements they will discover that they are > getting > more Hydrogen produced than can be accounted for by the energy input.
