Accelerated Thermal Decomposition of Graphene Oxide Films in Air via <i>in Situ</i> X-ray Diffraction Analysis

Abstract

Thermal decomposition of graphene oxide (GO) has been extensively investigated in the past decade, but the detailed reaction kinetics remains elusive so far. Here we employ an in situ X-ray diffraction (XRD) analysis to clarify the kinetics of GO decomposition in different atmospheres and sample morphologies. The XRD peak (002), which is the major diffraction peak corresponding to the interlayer distance in GO samples, shifted from 11.5° to 23° along with significant decrease in intensity when samples were heated from 25 to 350 °C. The decomposition in air exhibits a higher reaction rate compared with that in pure nitrogen gases because the O 2 molecules in air facilitate the oxidation of carbon atoms, leading to the evolution of CO and CO 2 . Free-standing films of GO also decompose significantly faster than GO powders, owing to their slower heat dissipation into the environment and higher thermal conductivity within the well-stacked lamella. This study has provided new insights into the reaction kinetics of GO thermal decomposition and offered a novel perspective on kinetic analysis based on our in situ XRD technique.