Synthesis of Multiple-Twinned Pd Nanoparticles Anchored on Graphitic Carbon Nanosheets for Use as Highly-Active Multifunctional Electrocatalyst in Formic Acid and Methanol Oxidation Reactions

Although direct formic acid fuel cells and direct methanol fuel cells have attracted a lot of interest owing to their high energy-conversion efficiency and low pollutant emissions, their large-scale commercial applicability is limited by lack of suitable catalysts that exhibit high activity and are cheap. Here, a synergistic morphology and defect engineering strategy for the “clean” synthesis of multiple-twinned Pd nanoparticles on nitrogen-doped low-defect graphitic carbon nanosheets (Pd/NL-GCN) without using a template or surfactant are presented. The unique grain-boundary-enriched multiple-twinned Pd nanoparticles provide a large number of catalytically active sites, while the graphitic carbon frameworks with a modulated electronic structure afford high electron conductivity as well as strong poison tolerance. Consequently, the Pd/NL-GCN hybrid shows outstanding catalytic performance with respect to the oxidation of formic acid and methanol, exhibiting a large electrochemically active surface area, high mass activity, and good long-term durability. Moreover, the catalyst outperforms conventional Pd-nanoparticle-based catalysts supported on carbon black, carbon nanotubes, and graphene materials.