Au hollow nanospheres on graphene support as catalyst for sodium borohydride electrooxidation

The Au hollow nanospheres on graphene support (HNAu/G) are prepared by galvanic replacement reaction between sacrificial cobalt nanoparticles and AuCl4− ions. The reaction is conducted at room temperature in aqueous solution. The prepared HNAu/G is used as the anode electrocatalyst for sodium borohydride electrooxidation. The physical and electrochemical properties of as-prepared electrocatalyst are investigated by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV), chronoamperometry (CA), and chronopotentiometry (CP). The results show that Au hollow nanospheres on graphene support are coreless with the size of about 18 nm. The Au hollow nanospheres on graphene support exhibit an enhanced electrocatalytic performance for borohydride electrooxidation compared with the solid Au nanoparticles on graphene support (NAu/G).