Regioselectivity control of graphene functionalization by ripples

Area of Science:

• Materials Science
• Computational Chemistry
• Surface Science

Background:

• Graphene sheets exhibit natural ripples.
• Controlling chemical reactivity in graphene is crucial for its applications.
• Understanding the impact of structural deformations on graphene's properties is an active research area.

Purpose of the Study:

• To investigate how ripples in graphene influence its chemical reactivity, specifically towards hydrogenation.
• To determine the conditions under which rippling enhances graphene's reactivity for functionalization.
• To explore the potential for regioselective control in graphene chemistry.

Main Methods:

• First-principles calculations were employed to model graphene structures and their reactivity.
• Analysis focused on the pyramidalization angles of carbon atoms in rippled graphene.
• The energetic favorability of hydrogenation was assessed based on ripple geometry (amplitude-to-wavelength ratio).

Main Results:

• Altering carbon atom pyramidalization angles in rippled graphene directs hydrogenation reactivity.
• Carbon atoms at ripple crests and troughs exhibit significantly increased reactivity.
• Hydrogenation becomes exothermic for rippled graphene when the amplitude-to-wavelength ratio reaches approximately 0.55.
• Rippling itself does not alter the graphene band gap, but rippling-induced hydrogenation does.

Conclusions:

• Graphene ripples provide a mechanism for regioselective control of hydrogenation.
• This approach offers a practical method for targeted functionalization of graphene.
• The findings open avenues for designing graphene-based materials with tailored chemical properties.