Fabrication of dendritic PdCu alloy supported on 3D N-doped hollow graphene for efficient ethanol electrooxidation

Fabricating highly efficient Pd-based nanocatalysts with a well-defined structure is desired for the commercialization of direct ethanol fuel cell (DEFC). Herein, a series of hierarchical three-dimensional N-doped hollow graphene spheres (NHGS) supported dendritic PdCu alloy catalysts Pd_xCu_(d)-NHGS (x: Cu/Pd theoretical molar ratio of 4, 2, and 1) are assembled by one-pot ascorbic acid reduction-immobilization method. Aiming to maximize the Pd utilization and realize the efficient ethanol electrooxidation, this novel electrocatalyst offers potent activity sites and promotes electron and ion kinetics simultaneously. Characterization indicates that the as-obtained Pd₄Cu_(d) alloy nanoparticles with average sizes of approximately 55 nm are evenly dispersed on the NHGS supporting materials obtained by using the SiO₂ nanospheres template strategy. Three catalysts all exhibit enhanced electrocatalytic activity, of which the Pd₄Cu_(d)-NHGS shows the highest mass current activity (2683 mA mg_Pd^-1), which is 2.59 times of the commercial Pd/C toward ethanol electrooxidation in alkaline medium. Based on the results, we believed that the Pd₄Cu_(d)-NHGS could exhibit extensive application prospect in alkaline DEFC.