As we approach the temporary shutdown for the SLS 2.0 upgrade this autumn, PSI scientist Maarten Nachtegaal looks back on 15 years of scientific excellence in operando x-ray spectroscopy at the Swiss Light Source SLS. Throughout this time, the SLS has been instrumental in unraveling complex chemical processes , such as those involved in electrolysers. These are devices that use electricity to produce hydrogen (and simultaneously oxygen) from water. Thanks to light from the SLS, scientists could follow the catalytic species that participate in oxygen formation, which is the rate limiting reaction in electrolysers, under conditions of operation and prove that they form only when the material is active. This discovery has led to new ways to describe catalytic activity and design new catalysts. What science did the SLS make possible for you? Join us in honouring the past 22 years of scientific and technical excellence by sharing these with #ThankYouSLS! More about the SLS 2.0 upgrade project ► https://www.psi.ch/en/media/sls-20-upgrade More about electrolysers to store solar energy ► https://www.psi.ch/en/media/our-research/nanomaterial-helps-store-solar-energy-efficiently-and-inexp... #UpgradingSLS #SLS2.0 #LightSourceScience #WorldChangingScience #SynchrotronScience #ScienceForSociety #ScienceNeverStops