Submolecular Insights into Interfacial Water by Hydrogen-Sensitive Scanning Probe Microscopy

Area of Science:

• Surface Science
• Physical Chemistry
• Nanotechnology

Background:

• Water-solid interfaces are critical in diverse chemical and physical processes.
• Understanding surface water structure and dynamics at the molecular level is essential.
• Previous methods struggled to resolve submolecular details, especially proton positions.

Purpose of the Study:

• To review recent advances in H-sensitive scanning probe microscopy (SPM) techniques.
• To showcase applications in probing surface water structures, dynamics, and nuclear quantum effects (NQEs).
• To investigate water-ion interactions and their impact on interfacial ion transport.

Main Methods:

• Development of high-resolution scanning tunneling microscopy/spectroscopy (STM/S).
• Utilization of qPlus-based atomic force microscopy (qPlus-AFM) for weakly perturbative imaging.
• Employing H-sensitive SPM to discern proton positions and hydrogen-bonding networks.

Main Results:

• Atomic-scale characterization of surface wetting and H-bonding in low-dimensional ice.
• Quantitative assessment of NQEs in surface water, including proton tunneling and delocalization.
• Revealed hydration structure effects on interfacial ion transport using SPM.

Conclusions:

• H-sensitive SPM techniques provide unprecedented submolecular resolution of surface water.
• These methods are crucial for understanding hydrogen bonding, proton transfer, and NQEs.
• Future SPM studies will further elucidate complex water-solid interface phenomena.