Theoretical simulation of the reduction of graphene oxide by lithium naphthalenide

Abstract

Based on density functional theory, we investigated the mechanism of graphene oxide reduction by lithium naphthalenide (C₁₀H₈Li). C₁₀H₈⁻ easily reacts with GO to form a neutral C₁₀H₈ and the negatively charged GO, which can attach to Li⁺ ions to form lithium oxide on a graphene skeleton. The reduction mechanism is similar to the reduction of GO by metallic Li; the C₁₀H₈ is used to disperse Li in THF solution. Furthermore, the lithium oxide on GO can react with CO₂ to form Li₂CO₃ and be further reduced by MeOH washing. In the negatively charged GO, the carboxyl at the edge of GO transfers an electron to GO and releases a CO₂ molecule by overcoming a barrier of 0.19 eV. CO₂ can also be adsorbed by lithium oxide to form Li₂CO₃ that is tightly attached on graphene skeleton. After GO is partially reduced, the adsorption of CO₂ eliminates O in the form of Li₂CO₃ without any barrier. This mechanism can be helpful for further understanding the nature of GO reduction among various reducing agents and for exploring new and efficient GO reducing agents.