Geometry-Dependent Thermal Reduction of Graphene Oxide Solid

Graphene oxide (GO) sheets have been used as a building block to construct various bulk forms of graphene structures such as films, fibers, foams, and dense solids. Thermal reduction of GO, where GO actually undergoes a disproportionation reaction to yield reduced GO (r-GO), accompanied by evolution of carbonaceous gases, has critical influence over the mechanical, thermal, and electrical properties and chemical stability of the resulting bulk graphene solids. Here, we report that this thermal reduction process is geometry-dependent for bulk GO solids, including the peak temperature of reaction, reaction rate, the chemical composition of released gases, and the C/O ratio of the resulting r-GO products, which can be largely attributed to additional reactions between trapped reaction intermediates. The work enriches the knowledge base of GO materials and offers insights for further tuning of the thermal reduction of GO solids to obtain high performance engineering graphene materials.