Selective Oxidation of Carbon Monoxide In Hydrogen Streams Using Titania Supported Gold Catalysts.

[NNadir]

Fuel cells are not sources of energy, but they can, under some circumstances, dramatically increase the efficiency of energy conversions.

Some people advocate the use of fuel cells in cars, making the insufferably awful statement that fuel cell fueled cars would be "green" cars. The only way to make a car green is to paint it. Painted or not all cars are environmental disasters and always will be, because they are distributed energy, and distributed energy cannot be made safe or clean.


I personally do not support the car CULTure in any way, shape or form. I believe the car CULTure should be phased out immediately, along with the dangerous fossil fuels that support it, and the dangerous fossil fuel fig leafs put forth by the stupid BP funded "heckuva job" set lead by Amory Lovins and his fellow circus clown "heckuva job" Joe Romm, who as "climate czar" presided over a huge increase in dangerous fossil fuel waste dumping in Earth's atmosphere.

Nevertheless a fuel celled car - not they I expect them to ever exist on any kind of meaningful scale - would be somewhat less odious than a car fueled by BP's less than "Beyond Petroleum" destruction of the Gulf of Mexico's ecosystem.

Car CULTists, in their never ending quest to create complacency through wishful thinking like to represent with soothsaying and mysticism that someday (by 2050, usually, when conveniently most of them will be dead and not be called to task on the stupidity of their predictions) hydrogen will be available from wind power.

We had a lot of such stupidity represented here in past years, five or so years ago, about the "wind to hydrogen" scheme that powered 10 houses on the Norwegian Island of Utsira. A post mortem on this exercise is now available in the scientific literature, and, um, guess what? It's still in the "someday it might work" phase. Thank god we didn't invest all of the future of all future generations on a "wind to hydrogen will save our cars" strategy or, um, um, um, well did we?

Ignorance kills.

Almost all hydrogen today is produced from dangerous fossil fuels through a process known as reforming, which involves the high temperature oxidation of the dangerous fossil fuel in question - almost always dangerous coal or dangerous natural gas - by water, with the simultaneous reduction of the water to hydrogen gas. Usually this is conducted on an industrial scale in huge chemical reactors, consuming considerable energy to make the transformation.

Hydrogen obtained in this way is always contaminated with carbon monoxide, which needs removal by various means.

In situ oxidation of carbon compounds in fuel cells - the carbon compounds could be a dangerous fossil fuel, methanol or dimethyl ether, ethanol and even, believe it or not pure carbon, often involves a high temperature reformation reaction in which the actual fuel is hydrogen gas. This is small scale reforming reaction.

In a fuel cell, the performance is almost always limited by carbon monoxide, which deactivates many of the catalysts used in the fuel cells.

Thus it is interesting to read a paper about the selective oxidation of carbon monoxide in the presence of hydrogen gas: "Au/FeOx−TiO2 Catalysts for the Preferential Oxidation of CO in a H2 Stream."

Here's a link to the abstract:

http://pubs.acs.org/doi/abs/10.1021/ie900806r?prevSearch=%255Bauthor%253A%2BSangeetha%255D&searchHistoryKey=">Ind. Eng. Chem. Res., 2009, 48 (23), pp 10402–10407

From the text of the body of the paper, which is only available to subscribers or patrons of a good scientific library, we have the following interesting commentary in the introduction:

Gold was regarded as a catalytically inactive material for a long time due to its deep lying valence d band and very diffuse valence s and p orbitals.1 This situation has been changed in recent years with the discovery of the catalytic activity of gold nanoparticles.2 Gold catalysts have recently gained attention due to their potential for many reactions of both industrial and environmental importance. The most remarkable catalytic properties of supported gold have been first obtained for CO oxidation at sub ambient temperature by Haruta et al. in 1987.3 The studies made so far pointed out that the reactivity of gold is highly structure sensitive, and the preparation techniques play a major role in the synthesis of highly active gold catalysts.4 The most studied catalyst for preferential oxidation of CO in H2 stream is gold supported on TiO2 because it is one of the most active catalysts for this reaction at low temperature. The optimum gold particle size in these catalysts was found to be ∼3 nm. Studies on gold catalysts so far showed that the macroscopic gold is only weakly active for CO oxidation; Au in nanodispersed form, with strong metal-support interaction, leads to highly active catalysts.5,6 Several techniques, such as the coprecipitation,7 deposition-precipitation,8 chemical vapor deposition,9 impregnation,10 and photodeposition methods11 have been used for the synthesis of nanogold particles on metal oxides...

Of course, one needs to consider the stability of any residual oxygen in the stream, but precisely balanced one might imagine that catalytically poisonous CO might be removed from catalysts using a similar approach, perhaps a composite catalyst with a low concentration oxygen scheme.

It's esoteric, but I thought it interesting and remark on it here, for what it's worth.

[LARED]

1. A+ for hyperbole, and a quick question.

What do you have in mind to replace the despised car culture?

[NNadir]

3. Mass transit, shorter working hours, telecommuting, bicycles and rebuilding cities.

If, um, everybody on earth needs cars to survive, how do you account for the fact that half of humanity doesn't own cars?

What's your plan for not filling Earth's atmosphere with enough dangerous fossil fuel waste to place half of its coastal cities under water?

Tell us that it's just too difficult?

The problem on this planet is intellectual and moral laziness.

Have a nice couch potato "I'm not interested if it's too hard," kind of day.

[jpak]

2. So - what kind of car do you own?

Do you live in an "upscale" community - does it have a mall you can drive to?

:rofl: