Palladium Nanoparticles Encapsulated into Hollow N-Doped Graphene Microspheres as Electrocatalyst for Ethanol Oxidation Reaction

A new type of microsphere of graphene oxide (GO) encapsulated zeolitic imidazolate framework-8 (ZIF-8) was prepared through spray-drying methodology, and hollow N-doped graphene microspheres (ZGC) were then obtained by the calcination of the ZIF-GO (ZG) composite microspheres. The ZGC can be used as a supporting material anchoring Pd nanoparticles for ethanol oxidation reaction (EOR). This novel ZGC precursor offers several advantages over other materials. (i) The three-dimensional (3D) hollow structure contains highly order nanoporous, and nitrogen doped structures offer more activity sites for support catalysts and provide more space for catalysis reaction. (ii) The unique 3D structure can avoid the aggregation and deactivation of catalysts. (iii) The conversion of nanostructure of graphene and nanocarbon to microsphere structure offers easy handle process. The optimized ZGC has a high orderly hierarchical pore structure, and Pd/ZGC electrocatalyst shows higher electrocatalytic activity (2490 mA mg–1) t...