N-doped hollow carbon nanospheres embedded in N-doped graphene loaded with palladium nanoparticles as an efficient electrocatalyst for formic acid oxidation
Efficient electrocatalysts with a low cost,high activity and good durability play a crucial role in the use of direct form-ic acid fuel cells.Pd nanoparticles supported on N-doped hollow carbon nanospheres(NHCNs)embedded in an assembly of N-doped graphene(NG)with a three-dimensional(3D)porous structure by a simple and economical method were investigated as direct form-ic acid fuel cell catalysts.Because of the unique porous configuration of interconnected layers doped with nitrogen atoms,the Pd/NHCN@NG catalyst with Pd nanoparticles has a large catalytic active surface area,superior electrocatalytic activity,a high steady-state current density,and a strong resistance to CO poisoning,far surpassing those of conventional Pd/C,Pd/NG,and Pd/NHCN catalysts for formic acid electrooxidation.When the HCN/GO mass ratio was 1∶1,the Pd/NHCN@NG catalyst had an outstanding performance in the catalytic oxidation of formic acid,with an activity 4.21 times that of Pd/C.This work indicates a way to produce superior carbon-based support materials for electrocatalysts,which will be beneficial for the development of fuel cells.