Microcalorimetric quantification of hydrogen adsorption thermodynamics in water-solvated systems on Pt/C

proceeds more rapidly in the presence of co-adsorbed water as a consequence of hydronium shuttling enabled by the Volmer step. This case study illustrates a generalizable methodology to directly measure thermodynamic quantities for molecular and dissociative adsorption at solid-liquid interfaces at controlled thermodynamic activities of all species. We anticipate this form of measurement will serve as a foundation for connections between theory and experiment in pursuit of increasingly complex descriptions of chemical reactions in these environments.