Surface chemistry and catalysis confined under two-dimensional materials.

Area of Science:

• Materials Science
• Surface Chemistry
• Nanotechnology

Background:

• Two-dimensional (2D) materials exhibit strong in-plane bonding and weak interlayer interactions.
• Interfaces of 2D materials on substrates create confined spaces for chemical processes, leading to the field of 'chemistry under 2D cover'.
• Graphene, hexagonal boron nitride, and transition metal dichalcogenides serve as model systems for studying this new chemistry.

Purpose of the Study:

• To review the emerging field of chemistry under 2D cover.
• To highlight the role of 2D materials as nanocontainers and nanoreactors for chemical transformations.
• To discuss the modulation of surface chemistry and catalysis by 2D material confinement.

Main Methods:

• Review of existing literature on 2D material overlayers on solid surfaces.
• Analysis of intercalation of atoms and molecules within 2D materials.
• Examination of chemical reactions occurring in 2D confined spaces.

Main Results:

• Atoms and molecules can intercalate ultrathin 2D materials, forming 2D nanocontainers.
• Chemical reactions, including catalysis and electrochemistry, occur within these 2D confined spaces, acting as nanoreactors.
• 2D covers significantly modulate surface chemistry, weakening adsorption and enhancing reactions.

Conclusions:

• The confinement effect of 2D covers enables novel chemistry in confined spaces, termed 'catalysis under cover' and 'electrochemistry under cover'.
• This provides a framework for designing advanced nanocatalysts with 2D material shells for improved heterogeneous catalysis, electrochemistry, and energy conversion.