We’ve been calling graphene the nanomaterial of the new millennium, and among its many superpowers it looks like this ultra thin material with unique electronic properties could help lower the cost of renewable hydrogen fuel.
That’s great news for fans of hydrogen fuel cell electric vehicles (FCEVs). With lower process costs, you could see more hydrogen fuel stations powered by on site renewable energy, and the way would also be cleared for large scale power-to-gas systems driven by solar, wind or even tidal energy.
The Graphene Solution For Low Cost Hydrogen
Graphene is a sheet of carbon just one atom thick. Structurally it looks like chickenwire, and its unique electronic properties are tailor-made for application to renewable energy.
Somewhat ironically the new graphene-enabled catalyst, which could hasten the demise of petroleum fuel, comes straight out of Texas in a collaboration led by the lab of James Tour at Rice University, with the University of Texas at San Antonio and the University of Houston, along with the Chinese Academy of Sciences.
To get the significance of the new graphene catalyst, it’s helpful to recall that the active sites on a catalyst are at the surface, so the idea is to get the most action out of a material by increasing the ratio of surface to interior.
As Tour describes it, even when you get down to nanoscale particles, you wind up with a lot of interior atoms that “never do anything.” By introducing atom-thin graphene to the mix, the research team ended up with a material in which virtually all of the atoms driving the catalytic action are exposed.
Here’s a video showing the new material in action:
The new catalytic material is a blend of cobalt and graphene, which the team created by heating graphene oxide and cobalt salts. The study appears in the journal Nature under the title, “Atomic cobalt on nitrogen-doped graphene for hydrogen generation.”
In the introduction to the study, the research team makes it clear that the key to a sustainable hydrogen economy is the use of low cost, earth-abundant materials as catalysts for water-splitting. Platinum is the catalyst of choice today due to its high efficiency, but the tradeoff is cost.
Cobalt is one material that has caught the eye of researchers as a cheap substitute for platinum. The problem is its low efficiency as a catalyst, meaning there are too many interior atoms doing nothing. The solution is to disperse it on a substrate so that more atoms are exposed.
Graphene has been widely used in catalytic research for just such a purpose, but on a nanoparticle level rather than an atomic level. To dig down to the atoms — and to get your advanced catalytic material out of the lab and into the market — you need an efficient, low cost, scalable process for achieving the dispersion:
Here, we report an inexpensive, concise and scalable method to disperse the earth-abundant metal, cobalt, onto nitrogen-doped graphene (denoted as Co-NG) by simply heat-treating graphene oxide (GO) and small amounts of cobalt salts in a gaseous NH3 atmosphere. These small amounts of cobalt atoms, coordinated to nitrogen atoms on the graphene, can work as extraordinary catalysts towards HER [hydrogen evolution reaction] in both acidic and basic water.
Renewable Hydrogen And The Texas Connection
We’re more familiar with Rice University for its extensive graphene research for clean energy and energy storage applications as well as graphene’s “cousin” molybdenum, but last spring we also happened across a cobalt-based catalyst for renewable hydrogen under development by the Tour lab and its collaborators.
That iteration of the catalyst consisted of a thin cobalt-phosphate film, with the advantage of producing recoverable oxygen as well as hydrogen.
Rice University is also behind another approach to low cost, renewable hydrogen production that involves capturing high-energy electrons before they have a chance to cool down.
As we mentioned earlier it’s somewhat ironic that Texas, America’s icon of fossil fuel production, is now staking out a claim to renewable energy leadership.
Graphene research and low cost hydrogen production are just two of the latest examples. Texas is also a wind energy leader, thanks partly to its investment in the billion-dollar CREZ wind energy transmission line.
The state has been breaking its own wind-generated electricity records. Just yesterday the San Antonio Express-News noted the latest mark under the headline, “Texas blows away wind power record.”
At 12:30 am Thursday, the main Texas grid operator reported that nearly 37 percent of demand was met with wind power. The Electricity Reliability Council of Texas, which manages nearly 90 percent of the state’s electric needs, said it used 12,237.6 megawatts of wind power at the time. That bested a previous record set on Sept. 13 of 11,467 megawatts.
Do read the full article for the scoop on Texas’s wind energy leadership.
Meanwhile the state has also been sharing the love with its solar energy resources, the latest development in that regard being a new utility scale solar-plus-storage system aimed at increasing grid reliability for the state’s notorious “electricity island.”
Image (screenshot): YouTube via Tour Lab, Rice University, “a new catalyst made of nitrogen-doped graphene and cobalt atoms drawing hydrogen from water.”
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