Computational description of surface hydride phases on Pt(111) electrodes

Area of Science:

• Materials Science
• Surface Chemistry
• Electrochemistry

Background:

• Surface platinum hydride structures are hypothesized to influence electrocatalysis and cathodic corrosion on Pt(111).
• Previous research suggests platinum may form clusters with multiple hydrogen equivalents.

Purpose of the Study:

• To investigate and compare various surface hydride structures on Pt(111) using thermodynamic methods and density functional theory.
• To understand the role of hydrogen in binding subsurface or reconstructing the surface of Pt(111).

Main Methods:

• Density functional theory (DFT) calculations.
• Thermodynamic analysis of surface structures.
• Comparison of multiple hydrogen monolayer configurations on Pt(111).

Main Results:

• Identified stable multilayer hydrogen configurations on Pt(111), with hydrogen binding subsurface or reconstructing the surface.
• Observed specific formation potentials for 2, 3, and 4 ML H structures (-0.29 V, -0.36 V, and -0.44 V, respectively).
• The 3 ML H configuration showed reconstructed Pt surface with interstitial H atoms in square-planar and octahedral coordination.

Conclusions:

• The study provides insights into the operando surface state of Pt(111) during low-potential reduction reactions.
• Discovered stable surface platinum hydride structures that serve as plausible precursors for cathodic corrosion on Pt(111).