Reversible Basal Plane Hydrogenation of Graphene

TL;DR

This study demonstrates reversible hydrogenation of single-layer graphene using electron-induced dissociation of HSQ, revealing enhanced reactivity, controllable doping, and potential for electronic property manipulation.

Contribution

It introduces a method for reversible basal plane hydrogenation of graphene, highlighting its potential for tuning electronic properties.

Findings

Hydrogenation occurs faster on single-layer graphene than on double layers.

Hydrogen atoms can be thermally detached, enabling reversibility.

Photothermal heating allows ambient oxygen binding, inducing hole doping.

Abstract

We report the chemical reaction of single-layer graphene with hydrogen atoms, generated in situ by electron-induced dissociation of hydrogen silsesquioxane (HSQ). Hydrogenation, forming sp3 C-H functionality on the basal plane of graphene, proceeds at a higher rate for single than for double layers, demonstrating the enhanced chemical reactivity of single sheet graphene. The net H atom sticking probability on single layers at 300 K is at least 0.03, which exceeds that of double layers by at least a factor of 15. Chemisorbed hydrogen atoms, which give rise to a prominent Raman D band, can be detached by thermal annealing at 100~200 degrees C. The resulting dehydrogenated graphene is "activated" when photothermally heated it reversibly binds ambient oxygen, leading to hole doping of the graphene. This functionalization of graphene can be exploited to manipulate electronic and charge transport properties of graphene devices.