Concentration-dependent platinum nanoassemblies with morphology-controlled electroactivity and high durability for direct methanol fuel cells

Abstract

Platinum (Pt) nanoassemblies with different morphologies, such as nanospheres self-assembled from nanoparticles, multipolyhedral nanostructures built with octahedral nanocrystals, hollow nanospheres consisting of armed nanoparticles, and two-dimensional arrays arranged by nanocubes, were synthesized by a solvothermal approach. The concentration gradient of Pt monomers plays a key role in the architecture of the self-assembled nanostructures, which is attributed to the weak dissolution of the Pt precursor in high-viscosity solvent. As a consequence, the electrode prepared from hollow Pt nanospheres consisting of armed nanoparticles shows much higher performance in the methanol electro-oxidation process than others. Meanwhile, the electrodes prepared from these novel Pt nanoassemblies exhibited long-term durability for methanol electro-oxidation, compared to the electrode prepared from monodispersed Pt nanoparticles.