Electric Field Effect on the Reactivity of Solid State Materials: The Case of Single Layer Graphene

This manuscript reports the first example of charge‐doping‐induced reactivity enhancement in macroscopic‐sized solid state material. Single layer graphene is supported on a Si wafer that has a 300 nm thick SiO2 layer and is heated photothermally in air to ≈240 °C. Applying both positive and negative pulsed back gate voltages increases the rate of graphene oxidation, as measured by the change of ID/IG ratio using Raman spectroscopy. The fact that both electron and hole doping increase the reactivity argues against electrochemical oxidation and suggests a new mechanism is at play. The enhancement effect increases with the magnitude and the frequency of the square wave back gate voltage. Density functional theory calculations indicate that the activation barriers for O2 insertion into graphene and desorption of CO2 decrease in the presence of an electric field. This study suggests charge doping as a new approach that can modulate the reactivity of solid state materials in real time and compliment chemical‐based catalysis. Electric charge doping of graphene populates electrons (holes) onto its conduction (valence) band, which should reduce the carbon–carbon bond strength and increase its chemical reactivity. This new mechanism of catalysis was observed in the gas‐phase oxidation of graphene and further supported by density functional theory calculations.