Engineering three-dimensional nitrogen-doped carbon black embedding nitrogen-doped graphene anchoring ultrafine surface-clean Pd nanoparticles as efficient ethanol oxidation electrocatalyst

Abstract The engineering efficient electrocatalysts with low cost, high activity and robust durability for ethanol oxidation reaction (EOR) is vital for large-scale commercializing direct ethanol fuel cells. Herein, the “surface-clean” Pd nanoparticles anchored on the nitrogen-doped carbon black embedding nitrogen-doped graphene (Pd/NCB@NGS) with unique three-dimensional hierarchical architecture was fabricated through a self-assembly strategy followed by a surfactant-free chemical reduction. The size of Pd nanoparticles on NCB@NGS can be controlled without surfactant. As an electrocatalyst for EOR, the Pd/NCB@NGS displays improved electrocatalytic performance compared with commercial Pd/C and other counterparts, due to the prominent roles of unique three-dimensional hierarchical architecture with abundant nitrogen atoms. Particularly, the electrocatalytic EOR property of Pd/NCB@NGS-2 (the mass ratio of OCB/GO is 1:1) is optimal among the tested-electrocatalysts, owing to it balances the clash between increased nitrogen atoms and decreased electrical conductivity. This study also developed a superior carbon-based material for various electrocatalysts and beyond.