Reply #21: Such a catalyst would justify a patent entirely by itself ...

[eppur_se_muova]

entirely independently of the method used to create H2. (Thanks for the more detailed link, BTW.)

However, some things still require clarification -- note this peculiar claim:

For almost a century, scientists have tried and failed to “split water” cost effectively to produce hydrogen and oxygen. Our process does not produce oxygen (O2), which has no significant value and is an expensive and slow reaction. Unlike conventional electrolysis, where hydrogen and oxygen atoms are completely disassociated using a large voltage, we designed our reactions to use a very small voltage and only produce hydrogen (H2). By elegantly engineering the reaction kinetics toward H2 generation in conjunction with wastewater, our nanoparticles function as one-way machines that detoxify wastewater, and produce clean water and pure hydrogen in the presence of sunlight. No other energy source is required, making this an extremely economical and commercially viable approach to hydrogen production.

I'm seeing too much advertising copy, not enough science. If you're going to reduce H+ to H2 (by gaining e-), something, somewhere, has to be oxidized (lose e-). Normally, this is the O in H2O, which gets oxidized to O2. They're saying no O2 is produced, but they can produce Cl2 and Br2. It sounds as if they are describing (in obscure fashion) the photoinduced electrolysis of aqueous HCl and HBr:

2HCl ---> H2 + Cl2
2HBr ---> H2 + Br2

Which is easily done by standard electrolysis. Note also:

Waste steams containing acids, such as hydrogen bromide and hydrogen chloride from industrial facilities, can be processed to produce pure bromine and chlorine, which are valuable and marketable byproducts.

Both plausible and interesting, but there's a catch: If they need HCl and HBr to carry out this reaction, it's not going to make much of a dent in the energy market. So far, it looks like a (potentially profitable) way to convert *some* industrial waste streams to fuel and clean water, but the amount of H2 produced will be limited by the amount of HCl or HBr used (also by concentration, since the voltage is concentration-dependent). A good idea, but not a revolution in clean energy.




It really sounds like they have two good ideas here, but they don't fit together as advertised. If they are looking for a closed-loop energy transport system, it might be practical to do something like this:
1. Use their photoelectrolytic process to convert HCl to H2 + Cl2 (energy of sunlight is adsorbed)
2. Recombine (not necessarily in the same location) the H2 and Cl2 in a fuel cell to produce electricity, or mix them in a reactor to produce heat, with HCl being regenerated by either process (energy from sunlight now converted to heat or electricity).
Since I've just posted that idea on the Web, I would have a patent claim on it, but they wouldn't. :P

The STP Sabatier catalyst opens up the possibility of a similar closed loop using CH4 and O2, but that would require regeneration of O2 -- something which they've avoided doing.




ETA: There is one other thing about this which bothers me:

This allows our reactor to be very low cost and very simple, such as a glass vessel or even clear plastic bag. To achieve world scale operation, we envision acres of very inexpensive reactors installed on vacant, non-productive land, producing massive amounts of carbon neutral methane that can be piped into the existing natural gas infrastructure for everyday use in homes, power plants, factories, and vehicles.

Problem: the nanoparticle produces H2 (or CH4? Make up your minds!) at one end, Cl2 or Br2 at the other. H2 (or CH4) + Cl2 reacts explosively, triggered by, uh, light. H2 + Br2 should be safer to handle, but the volume of bromine in commercial use is very small, relative to such things as natural gas. H2 and Br2 will combined in the presence of a catalyst, and I suspect any catalyst that can convert CO2 to CH4 is going to react with Br2. So products will be consumed in situ as fast as they are produced, unless some provision is made to separate the two ends of the nanoreactor so that the two products escape into different vessels. Embedding them in a membrane might do that, as long as the majority of the ends are oriented the same way. If this system works, it's going to end up being more complicated than their optimistic description.