Enhancement of Interfacial Charge Transfer of TiO2/Graphene with Doped Ca2+ for Improving Electrical Conductivity

Imparting surface coatings with conductivity is an effective way to prevent fire and explosion caused by electrostatic discharge. TiO2 is a commonly used paint; however, intrinsic TiO2 has poor electrical conductivity. Herein, we develop a method to make TiO2 coating highly conductive by doping Ca2+ into the TiO2 lattice based on the introduction of graphene. It is demonstrated that doping Ca2+ increases the carrier density of TiO2 and its morphology changes from a sphere to a spindle shape, which increases the interfacial contact area between TiO2 and graphene. Therefore, resistivity can be greatly decreased due to the construction of fast charge transport pathways from TiO2 to graphene, resulting from an increase in the speed of interfacial charge transfer. In addition, the electronic properties of the samples are also studied through first-principles calculations before and after Ca2+ doping. The result of the theoretical analysis is in agreement with that of experiments. Thus, the lowest resistivity of Ca2+-TiO2/graphene can reach 0.004 Ω cm. Consequently, the feature of superior conductivity of the Ca2+-TiO2/graphene composite endows it with practical application potential in the field of antistatic coating.