Sugar + weed killer = potential clean energy source (glucose fuel cells)

[OKIsItJustMe]

http://byunews.byu.edu/archive09-Sep-sugar.aspx

Sugar + weed killer = potential clean energy source

A spoonful of herbicide helps the sugar break down in a most delightful way.Researchers at Brigham Young University have developed a fuel cell – basically a battery with a gas tank – that harvests electricity from glucose and other sugars known as carbohydrates.

The human body’s preferred energy source could someday power our gadgets, cars or homes.

“Carbohydrates are very energy rich,” said BYU chemistry professor Gerald Watt. “What we needed was a catalyst that would extract the electrons from glucose and transfer them to an electrode.”

The surprising solution turned out to be a common weed killer, as reported by Watt and his colleagues in the October issue of the http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JESOAN0001560000100B1201000001&idtype=cvips&gifs=Yes">Journal of The Electrochemical Society. Watt shares his wonderfully appropriate last name with his great-great-uncle http://en.wikipedia.org/wiki/James_Watt_(inventor)">James Watt, the inventor of the steam engine.

The effectiveness of this cheap and abundant herbicide is a boon to carbohydrate-based fuel cells. By contrast, hydrogen-based fuel cells like those http://www.gm.com/experience/technology/fuel_cells/index.jsp">developed by General Motors require costly platinum as a catalyst.

The next step for the BYU team is to ramp up the power through design improvements.

The study reported experiments that yielded a 29 percent conversion rate, or the transfer of 7 of the 24 available electrons per glucose molecule.

“We showed you can get a lot more out of glucose than other people have done before,” said Dean Wheeler, lead faculty author of the paper and a chemical engineering professor in BYU’s Fulton College of Engineering and Technology. “Now we’re trying to get the power density higher so the technology will be more commercially attractive.”

Since they wrote the paper, the researchers’ prototype has achieved a doubling of power performance. And they’re pursuing an even stronger sugar high.

[Nuclear Unicorn]

1. Always good to read articles like this. YAY human ingenuity!

Still when they started talking about how the body's preferred energy source could power devices I had flashbacks of The Matrix.


Don't tell the machines!

[tabatha]

2. Very neat.

[kestrel91316]

3. +10 When I read stuff like this, I regain a little hope for mankind.

[Chulanowa]

4. What's the herbicide?

What's it made from, and how harmful is it?

[OKIsItJustMe]

9. Viologens - (ex. Paraquat)

http://en.wikipedia.org/wiki/Viologen">Viologen

http://scitation.aip.org/journals/doc/JESOAN-ft/vol_156/iss_10/B1201_1.html

…

We report here a class of organic molecules that catalyze the oxidation of glucose and other carbohydrates under mild conditions, making possible a direct carbohydrate fuel cell. These catalysts are variations in cationic 1,1'-dialkyl-4,4'-dipyridyl compounds, called viologens, that form stable, low potential free-radical cations in the absence of O2. When viologens and carbohydrates react, the viologen catalyst oxidizes carbohydrates and is in turn oxidized by the anode current corrector or by O2, creating a viologen-mediated catalytic cycle culminating in carbohydrate oxidation by air. Formate and carbonate are major products, demonstrating the catalytic breaking of carbon–carbon bonds and the transfer of a large fraction of the electrons from the carbohydrates to O2.

…

[joshcryer]

11. Isopropyl viologen to be specific, from the paper:

IPV is isopropyl viologen; I and II are, respectively, 1,1-ethylene-2,2-bipyridinium dichloride and 1,2,3,6-tetramethyl-ethylene-2,2-bipyridinium dichloride.

They compare isopropyl viologen to the others and it consistently beats them out. Ethyl viologen was also used and had comparable results.

[PHIMG]

5. Wow two unrecs! Wonder how much Exxon/Opec paid for those.

[Festivito]

6. Herbicide. Hopefully not leading to an entire nation with Parkinson's.

Yeah, it's not proven.

[hunter]

7. Just you wait 'til Coca-Cola dominates the world's fuel business...

I'm waiting for sugar powered synthetic muscles so I can build my robot army and rule the world.

Seriously, this is interesting. I might enjoy a sugar-electric bicycle, but it looks like the current model fuel cell would have to exhaust a formate/carbonate solution.

"Wait up a minute, my bicycle has to pee!"

[hootinholler]

8. Potato clock? No. Potato Car! n/t

[eppur_se_muova]

10. Great potential for artificial organs, prosthetics and implants.

Currently, surgery is required to change batteries in pacemakers, insulin pumps, and the like. The idea that such devices might run off of the user's own blood sugar has been a dream for quite a long time. Now it's moving closer to reality.

Fueling artificial limbs might be a bit dicier, because of the throughput required. Maybe could work as a trickle recharge when activity was low, or emergency backup only.

NOT a way to fuel vehicles. Too much bulk involved in handling solutions. Carbohydrates are bulkier than oils anyway.

[OKIsItJustMe]

12. "Carbohydrates are bulkier than oils anyway."

So, I did some checking. They’re bulkier, but maybe not be as bad as you think.

http://en.wikipedia.org/wiki/Dextrose#As_an_energy_source

http://en.wikipedia.org/wiki/Energy_density#Energy_densities_ignoring_external_components

Storage type   …   Energy density by volume (MJ/L) …
…                  
Gasoline       …                 34.2
Diesel fuel    …                 37.3
…
Biodiesel      …                 33
…
Ethanol        –                 24
…
Sugars…        –                 26.2(dextrose)
…

If you could get the kind of efficiencies they suggest…

[eppur_se_muova]

13. Try energy/unit mass. (Should have said "heavier", not "bulkier"; Sorry for misstating.)

Specific gravity of oils will be ~0.7-0.8; solid sugars >1, so sugars will start to look a lot worse.

Each of the following represents a 2-electron change in oxidation state:

CH4 --> (CH2)n --> CnH2mOm --> CO --> CO2

as a consequence the available energy per carbon atom decreases from HCs to CHs, but the mass of the molecule roughly doubles.

[OKIsItJustMe]

14. Got it, I thought you were talking about volume, not mass

Yes, carbohydrates are clearly heavier.

[NNadir]

16. Why bother with the laws of thermodynamics when you have Wikipedia?

I have a paper in my files from a time that I was thinking about the biodiesel business - Bioresource Technology 70 (1999) 1-15 - in which the average composition of various oil feedstocks was given.

The following oils are dominated by the C-18 fatty acids, mono and di unsaturated: Corn, cottonseed, peanut, rapeseed (canola), soybean and sunflower.

All have between 65 and 90% C-18 acids, formula C₁₈H₃₆O₂.

The heat of combustion is 11376 kJ/mol, or 9.6 kcal/g.

For dextrose, formula C₆H₁₂O₆ the heat of combustion is 2830 kj/mol or 3.8 kcal/g.

The calculator is right here: http://home.fuse.net/clymer/rq/index.html

It is obvious, though, by inspection that glucose is more highly oxidized, and thus less energetic (in an oxygen atmosphere) than fatty acids.

There is, by the way, nothing particularly new about direct carbon fuel cells other than the fact that they are subject to less magical thinking than other kinds of fuel cells, and have not been as widely investigated as others, possibly because in general they need to be fairly hot to work.

A subset of this class of fuel cells is the molten carbonate cell, and one paper I have in my files on this subject Phys. Chem. Chem. Phys., 1999, 1, 5659-5664 is now more than 10 years old. The publication of this paper has not lead to a huge outbreak of dextrose powered Tesla fuel/cell electric cars.

[Javaman]

15. Almost sounds liike grandpa simpson...

"Bahhh a fax machine is nothing more than a waffle iron and a phone!"