Researchers Develop System for Photocatalytic Production of Hydrogen Without Noble Metal Catalyst
26 January 2008
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| The supramolecular system for photocatalytic H2 production uses Ruthenium (left) as the photosensistizer and cobaloxime catalytic centers (right). Click to enlarge. |
Researchers at the joint Laboratoire de Chimie et Biologie des Métaux (LCBM), CEA-CNRS-Université Joseph Fourier, have developed a new supramolecular system for the photocatalytic production of hydrogen that uses a cobalt-based catalyst rather than a noble metal catalyst. They reported on their work in the 4 January issue of the journal Angewandte Chemie International Edition.
In researching the redirection of photosynthesis for hydrogen production, scientists have developed molecular systems capable of both photosensitization, which captures light energy, and catalysis, which uses the energy collected to liberate hydrogen from water. To date, according to the LCBM team, all such systems developed to produce or use hydrogen rely on noble metals such as platinum for catalysts.
Current research focuses on developing alternative catalysts based on metals which are naturally more abundant and less expensive, such as those used by natural organisms (iron, nickel, cobalt, manganese).
The new supramolecular system developed by the LCBM researchers functions as both the light-harvesting photosensitizer and the catalyst. Hydrogen production is catalyzed by various cobaloxime centers with greater efficiency than comparable systems using noble metals (Pd, Rh and Pt), according to their results. The catalyst stability, CoII/CoI redox potential, and nucleophilicity of the cobaloxime moiety all affect the photocatalytic properties.
The system still uses Ruthenium as the photosensitizer; one of the next steps in this work will be finding an alternative.
While the ultimate goal is still to use water as a proton and electron source (to avoid adding an organic molecule), this outcome represents considerable progress towards the photoproduction of hydrogen, according to the team.
Resources
Aziz Fihri et. al. Cobaloxime-Based Photocatalytic Devices for Hydrogen Production. Angewandte Chemie International Edition, Volume 47, Issue 3, Pages 564 - 567
Horaay for nucleophilicity!!!! I think. >_<
More exciting details here... http://www.wiley-vch.de/contents/jc_2002/2008/z702953_s.pdf
Someone care to translate?
Posted by: domenick | 26 January 2008 at 09:06 AM
"...and nucleophilicity of the cobaloxime moiety all affect the photocatalytic properties."
Oh yeah, I am all for that :)
Seriously, if they can get a good yield at an affordable price with less exotic materials, great. Hydrogen is put to a lot of good uses and reforming natural gas or splitting water using electricity make it expensive.
Posted by: sjc | 26 January 2008 at 09:27 AM
Sounds like education, research, spinnoffs are going to play an incresing part as humans evolve.
Where would we be without science and research? These science based advances should remind us all of the value of an educated population.
When we look out the window and observe the activities of our fellow man what behaviour do we see.
Hope we can see constructive efforts and good outcomes in the educational sphere as it matters like never before.
Posted by: arnold | 26 January 2008 at 03:22 PM
If we can produce photolytic hydrogen directly from water at reasonable efficiency (even 5%), it makes carbon capture and carbon recycling a far better prospect than it is otherwise. Electrolytic hydrogen is just too expensive.
Posted by: Engineer-Poet | 26 January 2008 at 06:40 PM
Since synthesis gas from biomass has extra carbon, you either sequester it, gas shift the CO or combine with more H2 for more methane. This might help to do that at lower cost.
Posted by: sjc | 26 January 2008 at 09:17 PM
Did anyone else notice that Ru IS a noble metal?
Hey, I invented a car that needs no engine at all!!*
*(except when driving on flat, uphill, or accelerating, but we're working on that....DOWNHILL IS GREAT!!)
Posted by: Kevin | 28 January 2008 at 05:25 AM
In the 1900s we used to make hydrogen gas by inserting a pos and a negative electrode into a mason jar filled with water. I was recently surprised to see an email site named "save gas use water" cut and paste the site shown below. They run regular cars on water (hydrogen} all the time. They even offer a kit for $39.00 that will allow you to run your car on water.
http://www.savegasusewater.com/?gclid=CNWWqLPrlpECFQSOFQodRHekOQ
Posted by: Leo Wells | 28 January 2008 at 09:46 PM
In the 1900s we used to make hydrogen gas by inserting a pos and a negative electrode into a mason jar filled with water. I was recently surprised to see an email site named "save gas use water" cut and paste the site shown below. They run regular cars on water (hydrogen} all the time. They even offer a kit for $39.00 that will allow you to run your car on water. Check it out.
http://www.savegasusewater.com/?gclid=CNWWqLPrlpECFQSOFQodRHekOQ
Posted by: Leo Wells | 28 January 2008 at 09:48 PM
Leo, you can't run your car on water. That website is pure weapons-grade bolognium. There are so many basic science mistakes and pure lies on that site, I can't even begin.
Posted by: John Bolhuis | 29 January 2008 at 07:59 AM