Preparation and electrochemistry of graphene nanosheets–multiwalled carbon nanotubes hybrid nanomaterials as Pd electrocatalyst support for formic acid oxidation

Graphene nanosheets–MWCNTs (GNS–CNTs) composites were synthesized by in situ reduction method, and then palladium nanoparticles (NPs) were supported on the GNS–CNTs by a microwave-assisted polyol process. Microstructure measurements showed that the graphene nanosheets and the CNTs formed a uniform nanocomposite with CNTs absorbed on the graphene nanosheets surface and/or filled between the graphene nanosheets. Compared to Pd/Vulcan XC-72R carbon, Pd/GNS, or Pd/CNTs catalysts, the Pd/GNS–CNTs catalysts exhibit excellent electrocatalytic activity and stability for formic acid electro-oxidation when the mass ratio of GO to CNTs is 5:1. The superior performance of Pd/GNS–CNTs catalysts may arise from large surface area utilization for NPs and enhanced electronic conductivity of the supports. Therefore, the GNS–CNTs composite should be a promising carbon material for application as electrocatalyst support in fuel cells.

► Graphene nanosheets–MWCNTs (GNS–CNTs) composites as Pd electrocatalysts support were synthesized by in situ reduction method.
► The direct electrooxidation of HCOOH is improved on the GNS–CNTs based catalyst.
► Both activity and durability of GNS–CNTs based catalyst are improved greatly.
► Pd/GNS–CNTs catalysts exhibit excellent performance when the mass ratio of GO to CNTs is 5:1.