Ian McCrum

Jan 22, 2025 | nature.com | Angel T. Garcia-Esparza |Selwyn Hanselman |Thijs Hoogenboom |Ian McCrum |Jeremy T. Feaster |Thomas F. Jaramillo | +9 more

Cathodic corrosion is an electrochemical phenomenon that etches metals at moderately negative potentials. Although cathodic corrosion probably occurs by forming a metal-containing anion, such intermediate species have not yet been observed. Here, aiming to resolve this long-standing debate, our work provides such evidence through X-ray absorption spectroscopy. High-energy-resolution X-ray absorption near-edge structure experiments are used to characterize platinum nanoparticles during cathodic corrosion in 10 mol l−1 NaOH. These experiments detect minute chemical changes in the Pt during corrosion that match first-principles simulations of X-ray absorption spectra of surface platinum multilayer hydrides. Thus, this work supports the existence of hydride-like platinum during cathodic corrosion. Notably, these results provide a direct observation of these species under conditions where they are highly unstable and where prominent hydrogen bubble formation interferes with most spectroscopy methods. Therefore, this work identifies the elusive intermediate that underlies cathodic corrosion. Cathodic corrosion of platinum is investigated using operando high-resolution X-ray absorption spectroscopy matched with density functional calculations. Platinum hydrides are found to be reaction intermediates in conditions at which these species are expected to be unstable.