Using platinum-molybdenum carbide to catalytically release hydrogen to power a fuel cell

March 31, 2017 by Bob Yirka report
Reaction path for hydrogen production from methanol and water. Credit: (c) Nature (2017). DOI: 10.1038/nature21672

(Phys.org)—A team of researchers from several institutions in China and the U.S. has developed a way to use platinum–molybdenum carbide to catalytically release hydrogen from methanol and water to power a hydrogen fuel cell. In their paper published in the journal Nature, the team describes the new method to produce hydrogen for possible use in a fuel cell.

As the planet continues to heat up, scientists around the world seek ways to power automobiles in a way that are as economical as gasoline. Such efforts have led to electric vehicles, hybrids, cars and trucks running on natural gas, ethanol and other fuels, and of course, the ever-elusive hydrogen fuel cell. In this new effort, the researchers suggest they may finally have found a way to make the last option viable.

Currently, there are a number of ways to obtain hydrogen for use in fuel cells, but thus far, none of them have proved economical enough to supplant the use of gasoline as the primary for automobiles around the globe. In this new effort, the researchers suggest they may have come up with a process that could make vehicles more practical.

The process involves using a new catalyst, platinum–molybdenum carbide, to drive a reaction that results in the production of H2 and releases . The team reports that the process can be done at temperatures from 150 to 190 C° and avoids the use of caustic materials. They claim it is five times as efficient as other techniques that use . They also claim that a car with a 50 liter tank of methanol and just six to 10 grams of their catalyst could power a Toyota Mirai for approximately 690 km. Also, it would cost just $15 for the methanol and $320 for the platinum, which the team suggests, might be recyclable.

The group acknowledges that a process that releases carbon dioxide is not ideal, but note that many hydrogen-producing industrial processes do so, as well. They acknowledge that platinum is extremely expensive, but point out that current catalytic converters have approximately one to four grams of recyclable noble metals that could conceivably provide a source.

Explore further: Toyota recalls all fuel-cell Mirai vehicles

More information: Lili Lin et al. Low-temperature hydrogen production from water and methanol using Pt/α-MoC catalysts, Nature (2017). DOI: 10.1038/nature21672

Abstract
Polymer electrolyte membrane fuel cells (PEMFCs) running on hydrogen are attractive alternative power supplies for a range of applications1, 2, 3, with in situ release of the required hydrogen from a stable liquid offering one way of ensuring its safe storage and transportation4, 5 before use. The use of methanol is particularly interesting in this regard, because it is inexpensive and can reform itself with water to release hydrogen with a high gravimetric density of 18.8 per cent by weight. But traditional reforming of methanol steam operates at relatively high temperatures (200–350 degrees Celsius)6, 7, 8, so the focus for vehicle and portable PEMFC applications9 has been on aqueous-phase reforming of methanol (APRM). This method requires less energy, and the simpler and more compact device design allows direct integration into PEMFC stacks10, 11. There remains, however, the need for an efficient APRM catalyst. Here we report that platinum (Pt) atomically dispersed on α-molybdenum carbide (α-MoC) enables low-temperature (150–190 degrees Celsius), base-free hydrogen production through APRM, with an average turnover frequency reaching 18,046 moles of hydrogen per mole of platinum per hour. We attribute this exceptional hydrogen production—which far exceeds that of previously reported low-temperature APRM catalysts—to the outstanding ability of α-MoC to induce water dissociation, and to the fact that platinum and α-MoC act in synergy to activate methanol and then to reform it.

Related Stories

Toyota recalls all fuel-cell Mirai vehicles

February 15, 2017

Toyota said Wednesday it is recalling all the Mirai fuel-cell vehicles it has sold globally due to a software glitch that can shut off its hydrogen-powered system.

Carbon leads the way in clean energy

March 22, 2016

Groundbreaking research at Griffith University is leading the way in clean energy, with the use of carbon as a way to deliver energy using hydrogen.

Recommended for you

6 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

Eikka
not rated yet Mar 31, 2017
Only, methanol is a horribly toxic fuel.

And solid oxide fuel cells can burn it directly without conversion. The PEM fuel cell that requires pure hydrogen is just a red herring.
Davy_Crockett
not rated yet Mar 31, 2017
Interesting but useless on the scale of 4000,000,000 units needed. Offers increased complexity and end-to-end energy delta with no range advantage when compared to battery-electric or gasoline cars. Waste product is CO2. Where can you get 10 grams of Platinum for $320? Back to square one.
plastikman
5 / 5 (1) Mar 31, 2017
Wasn't the point of developing fuel cell for cars not to be producing CO2 as exhaust?
Davy_Crockett
not rated yet Mar 31, 2017
I guess the CO2 mentioned in the article comes during the production of methanol whereas the diagram shows the catalytic waste product is CO. Other processes for generating H+ also end up with CO. Previous articles have stated that it is energetically possible to dissociate CO but no one to my knowledge has made that chemical engineering breakthrough with a further catalytic process.
Eikka
not rated yet Apr 02, 2017
Wasn't the point of developing fuel cell for cars not to be producing CO2 as exhaust?


That depends on who you ask.

CO2 is not a pollutant, but it's a greenhouse gas. The pushers of the hydrogen economy however play it as a pollutant to justify their own cause.

If you don't treat CO2 as a pollutant, then it becomes a question of where the carbon is sourced - i.e. if the fuel is carbon neutral. If so, then there's absolutely no point why a fuel cell shouldn't output CO2 as exhaust, as the CO2 is not a problem any more than you or I exhaling it.

Davy_Crockett
not rated yet Apr 05, 2017
When you drive 2 km today you emit about 300 X as much CO2 as when you walk. If PEM brings this multiple way down, then good.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.