Interconversion of hydrated protons at the interface between liquid water and platinum

Area of Science:

• * Physical Chemistry
• * Materials Science
• * Electrochemistry

Background:

• * Hydrogen transfer is crucial for electrochemical processes such as water splitting and the hydrogen evolution reaction (HER).
• * The atomic-level dynamics of hydrogen transfer at solid-liquid interfaces remain poorly understood.
• * Understanding these dynamics is key to improving catalytic efficiency in energy conversion technologies.

Purpose of the Study:

• * To investigate the atomic-level mechanisms of hydrogen transfer at the H2O/Pt(111) interface.
• * To elucidate the role of solid-liquid interactions and water molecule configurations in proton transfer.
• * To propose a detailed mechanism for hydrogen transfer in electrochemical environments.

Main Methods:

• * Utilized ab initio molecular dynamics (AIMD) for accurate simulation of dynamic processes.
• * Employed umbrella sampling (US) to calculate free energy barriers.
• * Focused on the H2O/Pt(111) interface to model the solid-liquid environment.

Main Results:

• * Calculated free energy barriers for hydrogen transfer at the H2O/Pt(111) interface.
• * Identified that solid-liquid interaction strength and water configuration govern proton transfer.
• * Discovered that surface-adsorbed cations enhance hydrogen transfer to and from the platinum surface.

Conclusions:

• * A multistep mechanism for hydrogen transfer at the H2O/Pt(111) interface has been proposed.
• * Surface-adsorbed cations play a critical role in facilitating hydrogen transfer.
• * Findings have significant implications for understanding and optimizing HER, water splitting, and other solid-liquid reactions.