Synthesis of Ordered Pt Nanocube Arrays Directed by Block Copolymer Nanotemplate and Their Potential on Ethanol Oxidation Reaction

Abstract

In this work, well-ordered platinum (Pt) nanocubes (NCs), with precise control on the size and the spatial arrangement, are synthesized from a microemulsion overgrowth in a block copolymer (BC) nanotemplate. The nanovials on this self-assembled BC template serve as microreactors for the reduction of the HCl/H2PtCl6 precursor and direct the ordered periodic arrangement of the reduced Pt nanoparticles (NPs). As the content of HCl increases from 0% to 25%, the Pt NPs evolve from quasi-spheres to NCs, for which the density functional theory (DFT) computation reveals that the different adsorption energies of Cl and HCl dominate this morphology transition. For their potential application in fuel cells, the electrochemical catalysis of the Pt NCs demonstrates a 2.8-fold mass activity in contrast to the commercial JM 40% catalyst at the same Pt loading in ethanol oxidation reaction (EOR) and a good stability of 2.2% ECSA loss over 10 »000 CV cycling.