Navigation Links
Catalyst that makes hydrogen gas breaks speed record

RICHLAND, Wash. -- Looking to nature for their muse, researchers have used a common protein to guide the design of a material that can make energy-storing hydrogen gas. The synthetic material works 10 times faster than the original protein found in water-dwelling microbes, the researchers report in the August 12 issue of the journal Science, clocking in at 100,000 molecules of hydrogen gas every second.

This step is just one part of a series of reactions to split water and make hydrogen gas, but the researchers say the result shows they can learn from nature how to control those reactions to make durable synthetic catalysts for energy storage, such as in fuel cells.

In addition, the natural protein, an enzyme, uses inexpensive, abundant metals in its design, which the team copied. Currently, these materials -- called catalysts, because they spur reactions along -- rely on expensive metals such as platinum.

"This nickel-based catalyst is really very fast," said coauthor Morris Bullock of the Department of Energy's Pacific Northwest National Laboratory. "It's about a hundred times faster than the previous catalyst record holder. And from nature, we knew it could be done with abundant and inexpensive nickel or iron."

Stuffing Bonds

Electrical energy is nothing more than electrons. These same electrons are what tie atoms together when they are chemically bound to each other in molecules such as hydrogen gas. Stuffing electrons into chemical bonds is one way to store electrical energy, which is particularly important for renewable, sustainable energy sources like solar or wind power. Converting the chemical bonds back into flowing electricity when the sun isn't shining or the wind isn't blowing allows the use of the stored energy, such as in a fuel cell that runs on hydrogen.

Electrons are often stored in batteries, but Bullock and his colleagues want to take advantage of the closer packing available in chemicals.

"We want to store energy as densely as possible. Chemical bonds can store a huge amount of energy in a small amount of physical space," said Bullock, director of the Center for Molecular Electrocatalysis at PNNL, one of DOE's Energy Frontier Research Centers. The team also included visiting researcher Monte Helm from Fort Lewis College in Durango, Colo.

Biology stores energy densely all the time. Plants use photosynthesis to store the sun's energy in chemical bonds, which people use when they eat food. And a common microbe stores energy in the bonds of hydrogen gas with the help of a protein called a hydrogenase.

Because the hydrogenases found in nature don't last as long as ones that are built out of tougher chemicals (think paper versus plastic), the researchers wanted to pull out the active portion of the biological hydrogenase and redesign it with a stable chemical backbone.

Two Plus Two Equals One

In this study, the researchers looked at only one small part of splitting water into hydrogen gas, like fast-forwarding to the end of a movie. Of the many steps, there's a part at the end when the catalyst has a hold of two hydrogen atoms that it has stolen from water and snaps the two together.

The catalyst does this by completely dismantling some hydrogen atoms from a source such as water and moving the pieces around. Due to the simplicity of hydrogen atoms, those pieces are positively charged protons and negatively charged electrons. The catalyst arranges those pieces into just the right position so they can be put together correctly. "Two protons plus two electrons equals one molecule of hydrogen gas," says Bullock.

In real life, the protons would come from water, but since the team only examined a portion of the reaction, the researchers used water stand-ins such as acids to test their catalyst.

"We looked at the hydrogenase and asked what is the important part of this?" said Bullock. "The hydrogenase moves the protons around in what we call a proton relay. Where the protons go, the electrons will follow."

A Bauble for Energy

Based on the hydrogenase's proton relay, the experimental catalyst contained regions that dangled off the main structure and attracted protons, called "pendant amines." A pendant amine moves a proton into position on the edge of the catalyst, while a nickel atom in the middle of the catalyst offers a hydrogen atom with an extra electron (that's a proton and two electrons for those counting).

The pendant amine's proton is positive, while the nickel atom is holding on to a negatively charged hydrogen. Positioned close to each other, the opposites attract and the conglomerate solidifies into a molecule, forming hydrogen gas.

With that plan in mind, the team built potential catalysts and tested them. On their first try, they put a bunch of pendant amines around the nickel center, thinking more would be better. Testing their catalyst, they found it didn't work very fast. An analysis of how the catalyst was moving protons and electrons around suggested too many pendant amines got in the way of the perfect reaction. An overabundance of protons made for a sticky catalyst, which pinched it and slowed the hydrogen-gas-forming reaction down.

Like good gardeners, the team trimmed a few pendant amines off their catalyst, leaving only enough to make the protons stand out, ready to accept a negatively charged hydrogen atom.

Fastest Cat in the West

Testing the trimmed catalyst, the team found it performed much better than anticipated. At first they used conditions in which no water was present (remember, they used water stand-ins), and the catalyst could create hydrogen gas at a rate of about 33,000 molecules per second. That's much faster than their natural inspiration, which clocks in at around 10,000 per second.

However, most real-life applications will have water around, so they added water to the reaction to see how it would perform. The catalyst ran three times as fast, creating more than 100,000 hydrogen molecules every second. The researchers think the water might help by moving protons to a more advantageous spot on the pendant amine, but they are still studying the details.

Their catalyst has a drawback, however. It's fast, but it's not efficient. The catalyst runs on electricity -- after all, it needs those electrons to stuff into the chemical bonds -- but it requires more electricity than practical, a characteristic called the overpotential.

Bullock says the team has some ideas on how to reduce the inefficiency. Also, future work will require assembling a catalyst that splits water in addition to making hydrogen gas. Even with a high overpotential, the researchers see high potential for this catalyst.


Contact: Mary Beckman
DOE/Pacific Northwest National Laboratory

Related biology technology :

1. Catalyst Pharmaceutical Partners Reports Second Quarter 2008 Financial Results
2. NIST and partners identify tiny gold clusters as top-notch catalysts
3. Catalyst Pharmaceutical Partners, Inc. Announces a $4.5 Million Registered Direct Common Stock Offering
4. Catalyst Pharmaceutical Partners to Present at the Rodman & Renshaw 10th Annual Global Investment Conference
5. PointCross Releases Catalyst for Building Business-Ready SharePoint Solutions in 1/10th the Time
6. Eurotech Catalyst Module Awarded to Allen Organ Company From Arrow Electronics
7. Coalition for the Advancement of Medical Research Releases New White Paper, Catalyst for Cures: Embryonic Stem Cell Research
8. New catalyst paves the path for ethanol-powered fuel cells
9. Brown chemists create more efficient palladium fuel cell catalysts
10. Catalyst Biosciences Expands Scientific Advisory Board With Leading Experts in Protease Therapeutic Discovery and Development
11. Researchers create catalysts for use in hydrogen storage materials
Post Your Comments:
Related Image:
Catalyst that makes hydrogen gas breaks speed record
(Date:11/24/2015)... /PRNewswire/ - Aeterna Zentaris Inc. (NASDAQ:  AEZS) (TSX: AEZ) (the ... the Toronto Stock Exchange, confirms that as of the ... developments that would cause the recent movements in the ... --> About Aeterna Zentaris Inc. ... Aeterna Zentaris is a specialty biopharmaceutical company engaged in ...
(Date:11/24/2015)... ... 2015 , ... The Academy of Model Aeronautics (AMA), led by its Executive ... Multirotor Grand Prix, to represent the First–Person View (FPV) racing community. , FPV racing ... this type of racing and several new model aviation pilots have joined the community ...
(Date:11/24/2015)... , Nov. 24, 2015 /PRNewswire/ - Aeterna Zentaris ... today that the remaining 11,000 post-share consolidation (or ... Warrants (the "Series B Warrants") subject to the ... on November 23, 2015, which will result in ... giving effect to the issuance of such shares, ...
(Date:11/24/2015)... , ... November 24, 2015 , ... ... OrthoAccel® Technologies, Inc., on being named to Deloitte's 2015 Technology Fast 500 list ... facility, OrthoAccel manufactures AcceleDent®, a FDA-cleared, Class II medical device that speeds up ...
Breaking Biology Technology:
(Date:11/17/2015)... Paris from 17 th until 19 ... from 17 th until 19 th November 2015. ... invented the first combined scanner in the world which scans ... now two different scanners were required: one for passports and ... the same surface. This innovation is an ideal solution for ...
(Date:11/17/2015)... Calif. , Nov. 17, 2015  Vigilant Solutions ... has joined its Board of Directors. ... Board after recently retiring from the partnership at TPG ... 107 companies with over $140 Billion in revenue.  He ... improvement across all the TPG companies, from 1997 to ...
(Date:11/16/2015)... SAN JOSE, Calif. , Nov 16, 2015 ... leading developer of human interface solutions, today announced ... new Synaptics TouchView ™ touch controller and ... the architectural revolution of smartphones. These new TDDI ... and include TD4100 (HD resolution), TD4302 (WQHD resolution), ...
Breaking Biology News(10 mins):