Oriented preparation and thermal conductivity of reduced graphene oxide-graphite phase carbon nitride composites by electrostatic self-assembly

The 2D face-to-face oriented hetero-layered composites reduced graphene oxide-graphite phase carbon nitride(RGO-g-C₃N₄) was fabricated by electrostatic self-assembly of RGO and g-C₃N₄ nanosheet. The g-C₃N₄ nanosheet and RGO was obtained by stripping the bulk multi-layer graphite carbon nitride (B-g-C₃N₄) and modified graphene oxide (GO) with polydiallyldimethylammonium chloride (PDDA), respectively. Zeta potential study shows that the process of self-assembly is influenced obviously by the Zeta potentials of RGO and g-C₃N₄ and the process is mainly controlled by charge neutralization. The characterization results of Raman spectroscopy and XPS indicate that the 2D layered RGO-g-C₃N₄ composites behave the common structural features of both g-C₃N₄ and RGO. The results of SEM and TEM also demonstrate that the layers of RGO and g-C₃N₄ are combined face-to-face in vertical direction and the RGO-g-C₃N₄ composites remain layer structure but with thickness increase obviously. The thermal conductivity of RGO-g-C₃N₄ composites is higher than that of simple mixture RGO+g-C₃N₄ with the same mass fraction of components. And the thermal conductivity of the RGO-g-C₃N₄ composites increases when RGO increasing. When the RGO content is 24.4 wt%, the thermal conductivity of the RGO-g-C₃N₄ composites is 4.2 W/(mK), which is 1.4 times of the thermal conductivity of RGO+g-C₃N₄ composites mixed simply with the same mass fraction of components.