Controllable synthesis of grain boundary-enriched Pt nanoworms decorated on graphitic carbon nanosheets for ultrahigh methanol oxidation catalytic activity

Abstract

A convenient and cost-effective approach is developed to produce ultrafine grain boundary-enriched Pt nanoworms grown on nitrogen-doped low-defect graphitic carbon nanosheets, which possess excellent electrocatalytic properties for methanol oxidation. • Controllable synthesis of 1D ultrafine Pt nanoworms is achieved. • Electronic-structure engineering endows the catalyst with numerous active sites. • The catalyst shows a high mass activity of 1949 mA mg −1 for methanol oxidation. • DFT calculations reveal the underlying catalytic mechanisms of the hybrid system. Although one-dimensional Pt nanocrystals have long been regarded as ideal electrode catalysts for fuel cells, the synthetic techniques commonly involve the use of various complicated templates or surfactants, which have largely hampered their large-scale industrial application. Herein, we present a convenient and cost-effective approach to the stereoassembly of quasi-one-dimensional grain boundary-enriched Pt nanoworms on nitrogen-doped low-defect graphitic carbon nanosheets (Pt NWs/NL-CNS). Benefiting from its numerous catalytically active grain boundaries as well as optimized electronic structure, the as-derived Pt NWs/NL-CNS catalyst possesses exceptionally good electrocatalytic properties for methanol oxidation, including an ultrahigh mass activity of 1949.5 mA mg −1 , reliable long-term durability, and strong poison tolerance, affording one of the most active Pt-based electrocatalysts for methanol oxidation reaction. Density functional theory calculation further reveals that the formation of worm-shape Pt morphology is attributed to the modified electronic structure as well as controllable defect density of the carbon matrix, which could also weaken the adsorption ability of Pt towards CO molecule and meanwhile synergistically promotes the catalytic reaction kinetics.