University of California – Davis physicists have come up with a new, simpler method to make a nanofoam of palladium. A nanofoam is a low density, porous material with very small pore size. The foamy metal could be used to store hydrogen in vehicles or for other purposes.

A nanofoam is what it sounds like – a foamy version of some material, filled with very small pores. First introduced about 20 years ago, metallic nanofoams have potential for diverse applications. The porous structures are strong and lightweight – like their natural counterparts of bone and cork. Palladium and certain other metal nanofoams can also rapidly store and release hydrogen, making them an ideal candidate for hydrogen fuel cells.

UC Davis physicists’ new simpler method to make a nanofoam of palladium is a low density, porous material with very small pore size. The foamy metal could be used to store hydrogen in vehicles or for other purposes. Image Credit: Dustin Gilbert and Kai Liu, UC Davis. Click image for the largest view.

But before cars can start fueling up via nanofoam, using metallic foams on an industrial scale must overcome challenges including demanding manufacturing conditions, contamination and poor crystallinity, said senior author Kai Liu, professor of physics in the UC Davis College of Letters and Science. It is also difficult to achieve extremely lightweight foams without compromising their stability, Liu noted.

Traditional metallic foam manufacturing techniques may require high temperature, high pressure and controlled chemical environments. The UC Davis-led team instead relies on a wet chemistry approach that is well-suited for industrial applications and adaptable to other types of lightweight metal foams as well, Liu explained. “This opens up a whole new platform for exciting materials explorations,” he said.

Lead author Dustin Gilbert pointed out, ‚ÄúThis opens up a whole new platform for exciting materials explorations.”

The team’s research paper has been published in Chemistry Materials.

The new technique uses nanowires of palladium as building blocks. The nanowires are put in water, then mixed into a slurry with ultrasonic vibrations. The slurry is quickly immersed in liquid nitrogen to freeze the wires in place. Finally, the ice-nanowire mix is placed in a vacuum until the ice vaporizes, leaving behind a pure palladium nanowire foam. The team found the density of the material is as low as one-thousandth of the density of palladium in it’s bulk metal form and can be tuned for different applications.

The researchers also studied the hydrogen storage properties of the palladium nanofoam, finding the material demonstrated excellent loading capacity and rate of absorption. The nanofoam exhibits excellent thermodynamic stability, as measured by specialized calorimetric techniques at the UC Davis Peter A. Rock Thermochemistry Laboratory. The laboratory is led by study co-author Alexandra Navrotsky, who holds the Edward Roessler Chair in Mathematical and Physical Science.

The research team is pursuing several new uses for low density metal foams and has filed patent applications for new manufacturing methods and air filters.

They’re off to a very good start with this new technology. Lots of basic data is still missing but will come overtime. One dies wonder how the air filter ideas gets to be the lead patent use.

Hydrogen, the smallest atom, is still the devil to contain and store. It wiggles out of most everything and often reacts with its containers.

Perhaps this material is a step on the path to economical, safe and effective hydrogen storage.


Comments

7 Comments so far

  1. Jagdish on November 8, 2017 11:38 AM

    While giving all credit to research, methanol may continue to be best storage for fuel cells.

  2. Jane on November 9, 2017 1:48 AM

    Hydrogen, the smallest atom, is still the devil to contain and store. It wiggles out of most everything and often reacts with its containers.

  3. Cast on November 9, 2017 2:01 AM

    The researchers also studied the hydrogen storage properties of the palladium nanofoam, finding the material demonstrated excellent loading capacity and rate of absorption.

  4. Theresa L. Kelly on November 9, 2017 9:39 PM

    The researchers also studied the hydrogen storage properties of the palladium nanofoam, finding the material demonstrated excellent loading capacity and rate of absorption.

  5. jack on November 15, 2017 12:28 AM

    Hydrogen, the smallest atom, is still the devil to contain and store. It wiggles out of most everything and often reacts with its containers.

  6. Aimix Group on November 15, 2017 12:37 AM

    The nanowires are put in water, then mixed into a slurry with ultrasonic vibrations. The slurry is quickly immersed in liquid nitrogen to freeze the wires in place.

  7. sica on November 15, 2017 12:40 AM

    Perhaps this material is a step on the path to economical, safe and effective hydrogen storage.

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