Direct observation of the ad- and desorption of guest atoms into a mesoporous host

Battery electrodes, storage devices for gases, and some catalyst materials have tiny functional pores that can accommodate atoms, ions, and molecules. How these guest atoms are absorbed into or released from the pores is crucial to understanding the porous materials’ functionality. However, usually these processes can only be observed indirectly. A team from the Helmholtz Zentrum Berlin (HZB) has employed two experimental approaches using the ASAXS instrument at the PTB X-ray beamline of the HZB BESSY II synchrotron to directly observe the adsorption process of atoms in a mesoporous model system. The work lays the foundations for new insights into these kinds of energy materials.

Most battery materials, novel catalysts, and storage materials for hydrogen have one thing in common: they have a structure comprised of tiny pores in the nanometer range. These pores provide space which can be occupied by guest atoms, ions, and molecules. As a consequence, the properties of the guest and the host can change dramatically. Understanding the processes inside the pores is crucial to develop innovative energy technologies.

Read more on the HZB website

Image: From the measurement data, the team was able to determine that the xenon atoms first accumulate on the inner walls of the pores (state 1), before they fill them up (state 2). The X-ray beam penetrates the sample from below.

Credit: ¬© M. K√ľnsting/HZB