Zundel-like and Eigen-like hydrated protons on a platinum surface

Area of Science:

• Surface chemistry
• Electrochemistry
• Physical chemistry

Background:

• Understanding hydrated proton behavior is crucial for electrode processes in acidic media.
• The formation site of hydrated protons (solution vs. electrode surface) in hydrogen evolution on platinum remains unclear.

Purpose of the Study:

• To investigate the formation mechanism and species of hydrated protons on a platinum electrode surface.

Main Methods:

• Utilized ultrahigh vacuum conditions.
• Employed mass spectrometry and infrared spectroscopy.

Main Results:

• Demonstrated direct conversion of hydrogen atoms to hydrated protons on a Pt(111) surface coadsorbed with hydrogen and water.
• Identified preferential stabilization of multiply hydrated species, specifically H5O2+ and H7O3+, over hydronium ions (H3O+).

Conclusions:

• Surface-bound hydrated protons, particularly multiply hydrated forms, are formed directly on platinum surfaces.
• These findings suggest a significant role for surface-bound hydrated protons in the hydrogen evolution reaction mechanism.