Scientists from Leiden University and the Department of Energy’s SLAC National Laboratory have made a significant breakthrough in understanding the rapid corrosion of platinum electrodes. The mystery behind platinum's degradation under negative polarization has been unraveled, pointing to the formation of platinum hydrides rather than platinides as previously believed. The research team utilized high-energy-resolution X-ray spectroscopy techniques at SLAC's Stanford Synchrotron Radiation Lightsource to observe platinum corrosion as it occurred in an electrolyte. By studying the X-ray spectra from the corroding platinum electrode, the researchers confirmed that platinum hydrides were responsible for the degradation. Through computational models and advanced X-ray science, the team demonstrated that platinum hydride formation was the key factor leading to the electrode's breakdown. This discovery opens new avenues for addressing platinum corrosion in electrolysers and other electrochemical devices, offering insights that can enhance green hydrogen production and sensor reliability. The project highlights the importance of collaborative expertise in scientific research and showcases the power of cutting-edge techniques in solving longstanding scientific questions. By advancing the understanding of platinum corrosion mechanisms, this breakthrough holds promise for the development of more affordable and sustainable hydrogen production methods.