The Melamine-Driven\nSolvation Effect Promotes Oxygen\nReduction on a Platinum Catalyst: Machine Learning-Aided Free Energy\nCalculations

The modification of Pt surfaces with organic compounds\nlike melamine\nenhances oxygen reduction reaction activity and catalyst durability.\nThrough first-principles free energy calculations utilizing thermodynamic\nintegration and finite-temperature molecular dynamics, enhanced by\nmachine learning force fields for efficient sampling of nanosecond-scale\ninterfacial water fluctuations and incorporating corrections to accurately\nreproduce first-principles free energies, we demonstrate that melamine\ndestabilizes OH adsorbates, facilitating their removal and enhancing\ncatalytic activity. Unlike alloys, where OH destabilization is driven\nby changes in electronic structure and surface strain, melamine disrupts\nhydrogen bonding between OH and interfacial water. Structural and\nvibrational analyses reveal that melamine alters the water solvation\nstructure, which is evident in modified radial distribution functions\nand a blue shift in the O–H stretching vibrations. These findings\nindicate that manipulating interfacial solvation with organic compounds\ncould be a promising approach to enhance catalytic activity without\ncompromising durability.