Nanoparticles could be turned into simple hydrogen reservoirs using a novel approach.
Depending on how the hydrogen gas is generated, the highly volatile gas could provide climate-friendly fuels for airplanes, ships, and trucks, as well as allow for climate-friendly steel and cement production. However, storing hydrogen is expensive: either the gas must be kept in pressurized tanks with pressures of up to 700 bar, or it must be liquefied, which requires cooling to minus 253 degrees Celsius. Both procedures require more energy.
Andreas Stierle of Deutsches Elektronen-Synchrotron (DESY) has led a team that has laid the groundwork for a new method of storing hydrogen: nanoparticles made of the precious metal palladium with a diameter of just 1.2 nanometers. Palladium’s ability to absorb hydrogen like a sponge has been known for a long time.
A core made of the rare precious metal iridium stabilizes the tiny particles, ensuring that they are sufficiently stable. They’re also attached to a graphene support, which is a very thin layer of carbon.
The X-ray source PETRA III at DESY was used to investigate what happens when palladium particles collide with hydrogen: The hydrogen essentially sticks to the nanoparticles’ surfaces, with very little of it penetrating inside. The nanoparticles resemble chocolates in appearance: A central iridium nut is encased in a palladium layer rather than marzipan, and the outside is chocolate-coated by the hydrogen. A small amount of heat is all that is required to recover the stored hydrogen; the hydrogen is quickly released from the surface of the particles because the gas molecules do not have to push their way out from inside the cluster.
